Conservation of marine birds of northern North America_ 921 downloads.pdf

The Project Gutenberg eBook of Conservation of marine birds
of northern North America
This eBook is for the use of anyone anywhere in the United States and most
other parts of the world at no cost and with almost no restrictions
whatsoever. You may copy it, give it away or re-use it under the terms of
the Project Gutenberg License included with this eBook or online at
www.gutenberg.org. If you are not located in the United States, you will
have to check the laws of the country where you are located before using
this eBook.

Title: Conservation of marine birds of northern North America

Editor: James C. Bartonek
David N. Nettleship

Release date: June 30, 2015 [eBook #49335]
Most recently updated: October 24, 2024

Language: English

Other information and formats: www.gutenberg.org/ebooks/49335

Credits: Produced by Richard Tonsing, Bryan Ness and the Online
Distributed Proofreading Team at http://www.pgdp.net (This
file was produced from images generously made available
by The Internet Archive/American Libraries.)

*** START OF THE PROJECT GUTENBERG EBOOK
CONSERVATION OF MARINE BIRDS OF NORTHERN NORTH
AMERICA ***

WILDLIFE RESEARCH REPORTS
This series comprises reports of research relating to birds, mammals, and
other wildlife and their ecology, and specialized bibliographies on these,
issued for wildlife research and management specialists. The Service
distributes these reports to official agencies, to libraries, and to researchers
in fields related to the Service's work.
Library of Congress Cataloging in Publication Data
Conservation of marine birds of northern North America.
(Wildlife research report: 11)
Supt. of Docs. no.: I 49.47/4:11
1. Sea birds—North America—Congresses. 2. Sea birds—Northwest,
Pacific—Congresses. 3. Birds, Protection of—North America—Congresses.
4. Birds, Protection of—Northwest, Pacific—Congresses. 5. Birds—North
America—Congresses. 6. Birds—Northwest, Pacific—Congresses. I.
Bartonek, James C. II. Natural Resources Council of America. III. United
States. Fish and Wildlife Service. IV. Series.
QL681.C59 333.9'5 79-607005
Use of trade names does not imply U.S. Government endorsement of
commercial products.

CONSERVATION OF MARINE BIRDS
OF NORTHERN NORTH AMERICA

CONSERVATION OF MARINE
BIRDS OF
NORTHERN NORTH AMERICA
Papers from the International Symposium

held at the Seattle Hyatt House,

Seattle, Washington, 13-15 May 1975

Edited by

James C. Bartonek and David N. Nettleship

Sponsored by
Natural Resources Council of America
National Audubon Society
National Wildlife Federation
U.S. Department of the Interior, Fish and Wildlife Service

UNITED STATES DEPARTMENT OF THE
INTERIOR
FISH AND WILDLIFE SERVICE
Wildlife Research Report 11
Washington, D.C. • 1979

Dedicated to the Memory
of
Robert D. Bergman, Leonard A. Boughton, and J. Larry Haddock, Wildlife
Biologists of the Fish and Wildlife Service, and Robert Johnson, Pilot of the
Office of Aircraft Services, all of the U.S. Department of the Interior, who
perished in the Gulf of Alaska on 30 September 1974 while conducting
aerial surveys of marine birds,
and to
Einar Brun, Professor of Zoology in Tromsø University and a contributor to
these proceedings, who perished in the Vega Sea on 13 July 1976 when
returning from making aerial surveys of marine birds.

Contents
Page
Foreword, by Harvey K. Nelson vii
Introduction, by Lynn A. Greenwalt ix
Marine Environment of Birds 1
Long-term Climatic and Oceanographic Cycles Regulating Seabird
3
Distributions and Numbers, by M. T. Myres
Sea Ice as a Factor in Seabird Distribution and Ecology in the
9
Beaufort, Chukchi, and Bering Seas, by George J. Divoky
Status of Marine Bird Populations 19
Distribution and Status of Marine Birds Breeding Along the Coasts
of the Chukchi and Bering Seas, by James C. Bartonek and 21
Spencer G. Sealy
Breeding Distribution and Status of Marine Birds in the Aleutian
Islands, Alaska, by Palmer C. Sekora, G. Vernon Byrd, and Daniel 33
D. Gibson
The Historical Status of Nesting Seabirds of the Northern and
47
Western Gulf of Alaska, by LeRoy W. Sowl
Status and Distribution of Breeding Seabirds of Southeastern
Alaska, British Columbia, and Washington, by David A. Manuwal 73
and R. Wayne Campbell
The Biology and Ecology of Marine Birds in the North 93
Trophic Relations of Seabirds in the Northeastern Pacific Ocean
95
and Bering Sea, by David G. Ainley and Gerald A. Sanger
Population Dynamics in Northern Marine Birds, by William H.
123
Drury
Time-energy Use and Life History Strategies of Northern Seabirds,
141
by Erica H. Dunn
Zoogeography and Taxonomic Relationships of Seabirds in
167
Northern North America, by M. D. F. Udvardy
Conflicts Between the Conservation of Marine Birds and Uses of
171
Other Resources

Social and Economic Values of Marine Birds, by David R. Cline,
173
Cynthia Wentworth, and Thomas W. Barry
Resource Development Along Coasts and on the Ocean Floor:
Potential Conflicts with Marine Bird Conservation, by Donald E. 183
McKnight and C. Eugene Knoder
Mortality to Marine Birds Through Commercial Fishing, by
195
Warren B. King, R. G. B. Brown, and Gerald A. Sanger
Interactions Among Marine Birds and Commercial Fish in the
201
Eastern Bering Sea, by Richard R. Straty and Richard E. Haight
Interrelations Between Seabirds and Introduced Animals, by
221
Robert D. Jones, Jr., and G. Vernon Byrd
Oil Vulnerability Index for Marine Oriented Birds, by James G.
227
King and Gerald A. Sanger
Programs and Authorities Related to Marine Bird Conservation 241
Programs and Authorities Related to Marine Bird Conservation in
243
Washington State, by Ralph W. Larson
Programs and Authorities of the Province of British Columbia
Related to Marine Bird Conservation, by W. T. Munro and R. 247
Wayne Campbell
Petroleum Industry's Role in Marine Bird Conservation, by Keith
251
G. Hay
Conservation of Marine Birds in Other Lands 259
Conservation of Marine Birds in New Zealand, by Gordon R.
261
Williams
Marine Birds in the Danish Monarchy and Their Conservation, by
267
Finn Salomonsen
Present Status and Trends in Population of Seabirds in Norway, by
289
Einar Brun
Symposium Summary 303
Conservation of Marine Birds of Northern North America—a
305
Summary, by Ian C. T. Nisbet
Appendix. Papers and oral summaries presented at the symposium
319
but which do not appear in this publication

Foreword
The international symposium "Conservation of Marine Birds of Northern
North America" was convened because of a growing awareness that not all
was well with our marine birds. The symposium provided a forum for
scientists, governmental administrators, conservationists, and laypeople to
discuss the diverse topics and issues that we must all understand if we are to
act both responsively and responsibly to assure that marine birds will not be
lost through our neglect.
The symposium was cosponsored by the Natural Resources Council of
America, National Audubon Society, National Wildlife Federation, and the
U.S. Department of the Interior, Fish and Wildlife Service; additional
support was provided by the Canadian Wildlife Service, the International
Association of Game, Fish, and Conservation Commissioners, the Pacific
Seabird Group, the Sierra Club, the Smithsonian Institution, the Wildlife
Management Institute, and the Wildlife Society.
Persons interested and knowledgeable in the many and varied aspects of
marine bird conservation were invited to participate in this symposium.
There were 139 registered and several score of unregistered participants in
attendance. Major topics treated were: (1) socioeconomic considerations
and conservation of marine birds; (2) the marine environment of birds; (3)
status of marine bird populations on land and sea; (4) the biology and
ecology of marine birds in the North; (5) conflicts between the conservation
of marine birds and uses of other resources; (6) programs and authorities
related to the conservation of marine birds; and (7) conservation of marine
birds in other lands.
The objective of the symposium was to identify problems and the needed
information and programs necessary for the conservation of marine birds of
northern North America. For the purpose of this symposium the term
"northern North America" referred to the coasts of Washington, British
Columbia, Alaska, Yukon Territory, and Northwest Territories and the
adjacent North Pacific and Arctic Oceans. "Marine bird" was defined as
being any bird using marine or estuarine waters. Speakers were asked to

describe the status of information or the state of the art as it pertained to
their topic within the limitations set by the objective of the symposium.
Examples from other regions and of bird species not found in the regions of
concern were to be used for comparative purposes when little pertinent
information was known for regions or species of concern. Speakers were
asked to identify the gaps in the knowledge and methodology that are most
critical to their topic.
I believe that this symposium was particularly successful in that it provided
a timely forum for many scientists who were about to embark on studies of
marine birds in those areas of Alaska and California being considered for
outer continental shelf oil and gas exploration and development. These
published proceedings may be of lesser importance from that standpoint
because some data, particularly those on populations, are out of date.
However, I believe that the proceedings will long be of importance to
biologists and administrators alike in charting their respective courses to
ultimately assure conservation of this valuable avian resource.
Many people from many organizations and agencies worked hard to put
together the symposium in the relatively short time of about 8 months.
Nathaniel P. Reed was the person primarily responsible for bringing this
symposium to fruition. The Steering Committee was composed of Daniel A.
Poole, John S. Gottschalk, David N. Nettleship, Amos S. Eno, C. Eugene
Knoder, Warren G. King, Louis Clapper, Robert Hughes, Fred G. Evenden,
James C. Bartonek, and me. James C. Bartonek, Warren G. King, David N.
Nettleship (Co-chairmen), C. Eugene Knoder, David A. Manuwal, William
H. Drury, and Spencer G. Sealy served on the Program Committee. David
A. Manuwal and Terence R. Wahl arranged trips for persons to observe
pelagic birds off the Washington coast and other birds on Skagit Flats. C.
Eugene Knoder handled financial matters. John A. Sayre and Richard Bauer
made arrangements for facilities and entertainment. Elaine Rhode prepared
the program and abstracts for printing. John Pitcher kindly contributed the
artwork used in this publication as well as that used in the program and
abstracts.
George Reiger made general introductions to the symposium; Spencer G.
Sealy, Daniel W. Anderson, and I served as Session Chairmen; and James
C. Bartonek served as General Chairman. Elvis J. Stahr was guest speaker
at the symposium banquet.

Most credit for the success of this symposium goes to the 52 persons who
as authors, coauthors, or summarizers of sessions presented much
meaningful information in their presentations, during recorded discussions,
and during many informal occasions. I wish to make special recognition of
Ian C. T. Nisbet for his skillful summary of the symposium.
Editorial assistance in preparing the proceedings was provided by Judith
Brogan.
Harvey K. Nelson

Chairman of Symposium and
Director of Wildlife Resources

Introduction
Migratory birds make up a resource that is shared by many people of many
nations. Public awareness of marine birds—their manifold values,
ecological requirements, and problems—is prerequisite to their protection. I
am proud that the Fish and Wildlife Service can further this needed
awareness by publishing these proceedings of the international symposium
"Conservation of Marine Birds of Northern North America."
Lynn A. Greenwalt, Director
Fish and Wildlife Service

MARINE ENVIRONMENT OF BIRDS

Long-term Climatic and Oceanographic Cycles Regulating
Seabird Distributions and Numbers

by
M. T. Myres
Department of Biology, University of Calgary
Calgary, Alberta, Canada T2N 1N4

Abstract

Seabird ornithologists have generally paid little attention to
the possible roles played by long-term climatic cycles or air-
ocean interactions on population changes at established
colonies or on the processes of colony establishment or
extinction. Yet, a rapidly expanding literature in the physical
sciences suggests that seabird numbers are not naturally
stable at particular colonies for any great length of time. It is
suggested that the establishment of new colonies at one end
of the range may counter the decline of colonies at the other
end. Perhaps these changes in small marginal colonies are
important, and they may be more indicative and significant
(when detected and explained) than are much larger changes
in numbers in bigger reproductive units in the center of a
species' range. Fluctuations in seabird numbers must in
future be first considered as possible responses either to
short-term, or turnarounds in longer term, natural climatic or
oceanographic cycles, or to trends ranging in length from a
few years to at least several decades.
During the last 30 years extensive literature in the fields of physical and
biological oceanography has accumulated that is not readily accessible to
the nonprofessional student of seabirds and not as widely understood by

career seabird ornithologists as it should be. This literature in oceanography
and marine fisheries is as extensive in Russian and Japanese together as in
the main languages of Western Europe combined; this abundance
compounds the problem of becoming familiar with it if, as a student of
seabirds, one's interest in the literature is initially somewhat marginal.
Nevertheless, to achieve the best possible appreciation of the oceanographic
influences affecting seabirds, particularly in the north Pacific Ocean and its
adjacent embayment seas, it is necessary to make the effort.
Because of the rigor of carrying out their primary duties while at sea, only a
very few North American and European oceanographers or fishery
biologists have found time to interest themselves in seabirds and then, with
a few notable individual exceptions, only as an off-duty pastime. The
reason is not far to seek. It is far less important to examine the ecology of
organisms at the next highest level of the food chain to the ones that are the
primary concern than it is to examine the next lowest level (the food of the
fishes or, in the case of phytoplankton, the physical and chemical
environment in which the organisms grow best).
Seabirds are at the very top of the marine food chain, and they are not
wholly aquatic in any case since they mainly travel through the air rather
than the water and reproduce on land rather than in the sea. Only with the
relatively recent recognition that seabirds contribute to the recycling of
nutrients back into the ocean to an important degree, have seabirds gained a
new scientific constituency.
At about the same time, governments have begun to recognize that seabirds
are relatively easily examined indicators of the presence of unseen chemical
pollutants in coastal seas, perhaps primarily for the very same reasons that
they were previously so largely ignored; namely, that they are at the top of
the food chains (and so accumulate the most-persistent and least-degradable
pollutants) and that the on-land failures in their reproductive biology are
readily visible.
During the last 10 years, it has become evident that yet another fundamental
science is even more basic to the achievement of a balanced and in-depth
understanding of the influence of the environment upon seabirds—the
combined field of astrophysics, geophysics, and climatology. New
developments in this field (when they are not published in Nature or

Science) appear in journals that are less familiar to seabird ornithologists
than those in which the fishery biologists and biological oceanographers
publish their findings.
Unfortunately, important advances in understanding the dynamics and
energy transport mechanisms of both the atmosphere and the water masses
of the oceans are not being picked up by students of seabirds because of the
natural lag in communication that occurs between disparate disciplines.
Only in the last few years have oceanographers and climatologists been
invited to address gatherings of ornithologists, and the modesty with which
they have sometimes done so has limited the impact of their offerings.
At this symposium, it was left to a biologist with no pretentions in either
physics or mathematics to demonstrate the need for seabird ornithologists to
understand basic environmental processes well beyond their usual range of
interests. I did so with a series of slides taken from this "other" literature,
and I had intended to include in the published version of this paper an
extensive bibliography, subdivided into category groupings, so that seabird
ornithologists could make their own selection of the points in the spectrum
at which they most needed information.
Unfortunately, limitations upon space in this volume, daily additions to the
exploding literature, and my own inability to keep up with understanding
this have forced me to omit any references and not to attempt to expound
detailed specific physical mechanisms.
Thus unencumbered here, I shall briefly outline instead what I perceive to
be some of the significance for seabird ornithology and conservation of the
rapidly expanding understanding of the oceans, the air-sea interface,
atmospheric dynamics, and influences upon the world's climate of
extraterrestrial events.

Small-scale or Short-term Influences

There is no need to dwell on the well-known events that could be
mentioned under this heading. Seabird ornithologists are familiar with the
fact that the atmosphere is the medium of seabirds both when searching the
ocean for feeding areas and when on migration, and also a violent enemy, as
when particular storms cause occasional "wrecks" of seabirds inland from

coastlines. As a refinement of the former, Manikowski of Poland suggests
that seabirds respond to the passage of weather systems, so that their
distribution over the open ocean may be constantly changing. Whereas
some species may attempt to avoid the stormy conditions of low-pressure
areas (cyclonic conditions), others more highly specialized for exploiting
the aerodynamic properties of wind over a moving water surface may
possibly, instead, try to avoid large high-pressure regions (anticyclonic
conditions with little or no wind). My student, Juan Guzman, is attempting
to determine whether this may be so; if it is, it might be possible, for
example, to predict some things about the distribution patterns and
population structure of southern hemisphere shearwaters while they are
visiting the oceans of the northern hemisphere during the nonbreeding
season.
In comparison with the "wrecks" brought about by storms, which are of
short duration and not usually very serious, seabird ornithologists are also
familiar with relatively brief and localized disasters caused by changes in
the ocean itself. The best-known example is a slight change in the boundary
of an ocean current (or other shift in the position of a distinctive water
mass) that results in the failure of food fishes to appear as they normally
would, close to breeding sites of conspicuous colonial seabirds, such as the
periodic shift in the El Niño off the west coast of South America. A scarcely
studied refinement of this type of event would be the effects of less-
pronounced oceanic changes that might reduce the planktonic food supply
of nocturnally active, burrow-nesting seabirds. In such instances, the effects
might also be a breeding failure for only one or two seasons; in all
probability such events occur, but whether they are as likely to be detected
by us is problematical. However, the populations of most seabirds are
probably already adapted to survive short-term crises of this type because,
having long adult life spans, reproductive adults that fail to raise young one
year may mostly live to succeed in doing so in the next or succeeding year,
when the oceanic "anomaly" has disappeared. What constitutes an
"anomaly" will be considered again shortly.
A third critical condition for seabirds may be local or widespread,
temporary or final, or some combination of these. A single local spill, or
outfall, of a chemical pollutant will be short term if we can take steps to
alleviate the consequences or stem the flow. Alternately, we may consider it

to be long term if we take the view that it is one additional act of violence
resulting from the "progress" of Industrial Man, and that it is never going to
shift into reverse gear. We may say that the effect on seabird populations of
spills of oil products or chemical pollutants in coastal waters of a region
will be a "final solution" for any that become wholly extinct before the oil
wells go dry or the industries fail. On the other hand, the effect will have
been merely a perturbation of the population if the species survives and
outlives these activities. Recent upturns in populations of peregrine falcons
(Falco peregrinus) and pelicans (Pelecanus sp.) in certain places where
environmental controls have been enacted give us hope that crises of
several years' duration can be withstood by at least those species that once
were common in relation to their respective food sources or available safe
breeding habitats. The really critical features to document are the means
whereby abandoned breeding sites are reoccupied and the time it takes.
It must never be forgotten that we know almost nothing about the ecology
of subadult or nonreproductive adult seabirds during the years they are at
sea unconfined by membership in a breeding unit and that we know almost
nothing about the activities of pelagic seabirds in the nonbreeding season.
These birds may be far from land and hard to study, but what happens
during those phases of their lives is basic to the composition of the colony
and condition of the birds when breeding. A start would be to learn
everything that is known and is being discovered about the oceans by
oceanographers and, thus forearmed, go looking for the seabirds with
certain questions clearly in mind.

Detecting the Effects of Long-term Cycles

A scientist's working life lasts only a few decades, and few studies of
seabirds by a single author or agency have been continued for longer than
5-10 years on any one problem. Further, while we as individuals may live to
be equally active in a certain field of research 20 years hence, our collective
conscience and collective muscle consist of several levels of government
that tend to exhibit 4- or 5-year changes of direction and priorities.
Certainly, the civil service may live on as an inertial recorder of collective
experience. Certainly, too, those who live under one form or another of
dictatorship or, as in some Canadian provinces, where conservative patterns

of voting occur, may experience a continuity of research and development
and conservation policies that exceed the 4- to 5-year turnaround pattern
that is most common. Yet, even these more continuous systems may come
to an end quite suddenly because of economic or political happenstance.
The point of this digression is to show that seabird ornithologists must not
rely on government programs to provide continuous data over a long period
of years—not, at least, in most countries. Monitoring the biological
circumstances of seabirds is not the same as recording the temperature
regularly by machine at a weather station, since this activity is unlikely to
be terminated unless the society collapses altogether. We may know that in
some countries the amateur naturalist exists in such numbers that records of
seabirds will continue to be made whatever the circumstances.
Nevertheless, planning of censuses that will be repeated every 10 years is
best assured if government and career biologists combine with the amateur
element, so that any one of them can continue the work if any other element
should be incapacitated. At any one time, either the amateur or the
government or the university personnel may be the prime mover, and each
of these forms now exists in various countries.
What the scientific literature in the fields of the geophysical, atmospheric,
and oceanographic disciplines demonstrates is that natural climatic
oscillations probably range in length from the 11-year sunspot cycle
through several decades (or a human lifetime) to several hundred years. So,
when our children are the new trustees of seabird colonies 20 or 40 years
hence, they must interpret their data using the full range of physical as well
as biological data that we can leave for them. Indeed, the information is, I
believe, already available over a long enough period (since 1940 at least) to
allow some speculative interpretations of what may have been happening to
our seabird populations, whether or not we knew or had any evidence of it.
I have already suggested that extraterrestrial events, particularly the 11-year
sunspot cycle, are increasingly believed to influence the atmosphere of this
planet. The Chinese and Japanese have remarkably precise records of the
northern limits of certain agricultural crops at particular times, the
phenology of flowering, and the freezing of lakes. These demonstrate long-
term trends in overall climate in eastern Asia that extend over hundreds of
years. The climate of Japan is influenced by the high-pressure area in winter
over mainland East Asia. There is evidence that severe ice conditions in the

Bering Sea during the early 1970's may have been due to an eastward
shifting of this high-pressure area. Again, the water mass of the Kuroshio
Extension and the West Wind Drift takes several years to travel across the
Pacific Ocean, and there is an established temperature variation that travels
like a slow wave with it. Off Japan, the Kuroshio Current periodically
develops meanders which slow the speed of the eastward flow. Cold and
warm "pools" of water approach the west coast of Canada and the western
United States from time to time.
Ocean currents are driven by the atmospheric motion above them, which
consists of several convective cells between the equator and each pole. The
outcome is zonal winds, such as the trade winds and the westerlies.
However, as the influence of the sun on the atmosphere is variable, the
input of heat and the extent of the major high-pressure areas vary, as does
the path of the jet stream. The recent droughts in northern Africa and
unusually heavy rains in Australia are both linked to a southward shift of
the Intertropical Convergence Zone in the atmosphere and a "corrugation"
of the wind circulation from a more normal zonal (latitudinal) path. These
shifts in the atmospheric circulation are almost certainly transmitted also to
the ocean currents and the marine ecosystem, with the influence being felt
for a long period of years.
One of the oceanic domains of the North Pacific is the transitional domain,
which lies east-west where the West Wind Drift impinges upon the coasts of
British Columbia and Washington State. It is precisely in this sector that
there was a well-documented "temperature anomaly" in 1957-58. Since an
anomaly implies something completely out of the ordinary, I seriously
question the appropriateness of the term for an event that may or may not
be recurrent (at the time it was a pronounced variation from the
oceanographic records accumulated up to that time, but the period had not
been a very long one). It is no coincidence that the numbers of albatrosses
recorded at Ocean Weather Station "Papa" was higher during this warm-
water "anomaly" than subsequently (indeed, an 18-year record of the
seabirds recorded at "Papa" also exhibits other interesting fluctuations from
the base-line data in certain years).
Recent analyses of sediments from off the coast of California have
demonstrated long-term fluctuations in sardine populations extending back
at least 1,800 years, with increases lasting 20-150 years and spaced 20-200

years apart. The number of anchovies declined steadily. Yet until now, El
Niño events have been treated as anomalies in that region as well as off the
coast of Peru. Just as we recognize that different species of fish follow the
warm water north on such occasions, we must also recognize the rather
distinct seabird species assemblage that is trapped, as it were, in the Gulf of
California. Clearly, like the termination point of the West Wind Drift at
about the 45-55° parallel, the coast of Baja California and southern
California State, from the 25-35° parallel where the California Current
begins to swing away from the coast to the west as the North Equatorial
Current, is another zone of instability.
I think that it is no accident that the southern limit of several northern
species of North Pacific seabirds ends in southeastern Alaska or northern
British Columbia, and that the northern limit of the ranges of several other
species occurs in Washington State or southern British Columbia. Indeed,
the west coast of Vancouver Island is not rich in species, and several of
those that exist are not present in great numbers. This is a region of rather
more variable conditions than elsewhere, and species evidently find that it
is difficult to colonize and it quickly becomes unsuitable again. Since 1940,
indeed, there has been a parallel decline in the annual mean sea-surface
temperature at a number of coastal recording stations in British Columbia,
and this seems to have been a rebound from a less well-documented rise in
sea-surface temperatures during the 20 years before that, which culminated
in a peak around 1940. Salinity has likewise trended downwards during the
last 30 years. The seabird colony size data before 1960 are so
nonquantitative that it is impossible to be sure what changes in seabird
populations and breeding sites may have taken place in response to these
physical changes.
The lesson is that we must now examine all future census and distribution
data with trends in sea-surface temperature and salinity in mind as two of
several likely factors influencing them. We must no more ignore data
outside our own field than a salmon ecologist might.

Conclusions

We know little of the accuracy of censuses of seabird numbers made
between 1850 and 1950. There has been a tendency to assume that numbers

of seabirds at long-established colonies have been relatively unchanging,
even though the expansion of some species into previously unrecorded
breeding sites in low numbers is well documented. Contraction of breeding
ranges, likewise, has most commonly been attributed to the influence of
man. Recent literature from the physical sciences, on the contrary, suggests
that seabird numbers at particular colonies are most unlikely to have been
stable for any great length of time, at least at high or middle latitudes and
particularly at points where boundaries between currents impinge on
continental coasts. Indeed, some early estimates of colony sizes may not
have been as much in error as we may have assumed, neither when
apparently too large nor when apparently unlocated by previous visitors.
The halving of a large colony over a period of 20 to 50 years in the middle
of the range of a species and the establishment and disappearance of smaller
breeding groups at opposite extremes of the range (both latitudinally and
longitudinally), may equally reflect natural long-term climatic or
oceanographic changes and may naturally be reversed at some time in the
future, perhaps within half a century. The implication for conservation of
seabird colonies that are at the contracting end of a species' range is that
cultural rather than biological criteria may be the best determinants.

Sea Ice as a Factor in Seabird Distribution and Ecology in the
Beaufort, Chukchi, and Bering Seas

by
George J. Divoky[1]
U.S. Fish and Wildlife Service
Fairbanks, Alaska

Abstract

Arctic sea ice has a variety of effects on seabirds. Although
the decrease in surface area available for feeding and
roosting is probably the major restrictive effect, also
important are productivity of water covered by ice and the
reduced prey abundance in nearshore areas due to ice scour.
The most important benefit that sea ice provides to seabirds
is the plankton bloom that occurs in the ice in the spring. In
the Beaufort and Chukchi seas this bloom supports an under-
ice fauna that is an important food source for seabirds.
Sea ice is a major factor in the distribution and ecology of many of the birds
treated in this symposium. Sea ice is defined here as ice formed by the
freezing of seawater and includes both free floating pack ice and the more
stable shorefast ice. Since icebergs are composed of ice of land origin, they
are not discussed.
Before discussing the specific relationship of birds and sea ice in the
Beaufort, Chukchi, and Bering seas, I list the general effects that arctic ice
can have on seabirds. For purposes of discussion these effects can be
divided into negative effects, or disadvantages, and positive effects, or
advantages.

General Effects of Ice on Birds

Negative Effects

Sea Ice Decreases the Surface Area of Water

The decrease in the surface area of water is the simplest and most
immediate effect that sea ice has on birds. Ice acts as a barrier that restricts
the availability of food in the water. Surface feeders are the most severely
affected since, in general, ice cover of 50% reduces the possible feeding
area by half. The effect on diving species is not as severe since, if open
water is scattered throughout the ice, diving species still have access to
much of the prey in the water column and benthos. When open water is
scarce, however, diving species can become concentrated in the available
water, resulting in intense competition for available prey. In certain
situations the open water is used only as a migratory pathway, but open
water is necessary for birds that must roost or feed.

Sea Ice Reduces Primary Productivity in the Water Column

Ice inhibits phytoplankton blooms in the water column, thus decreasing the
biological productivity of ice-covered waters. This inhibition occurs in two
ways:
• By decreasing light penetration of the water column.—Much of the
sunlight reaching the ice is reflected by the ice and by snow on the ice. The
amount of light reaching the water depends on the angle of the light,
thickness of ice, and amount of snow cover. When the layer of under-ice
algae forms, it absorbs light and further reduces the amount of light
reaching the water (Bunt 1963). This reduction in light reduces the depth of
the euphotic zone.
• By increasing the stability of the water column.—Increased stability of the
water column reduces the upwelling of nutrient-rich waters into the
euphotic zone. Ice stabilizes the water column primarily by preventing
wind-driven movement of surface waters and by forming a layer of
meltwater at the surface in the spring and summer (Dunbar 1968).

Sea Ice Reduces Benthic and Intertidal Biota

Benthic flora and fauna can be reduced by the presence of ice in two ways:
In shallow water ice can freeze to the bottom for much of the year and
prevent the establishment of plant and animal populations; and when ice
floes are pushed together, they form underwater ice keels that can scour the
bottom when the ice moves. Both of these events not only act directly to
decrease benthic populations but also disturb the sediment, making it less
suitable for colonization. In areas with heavy ice scour, sessile benthic
populations can be greatly reduced, although motile species may move into
scoured areas during the ice-free period in summer. In addition to
preventing the establishment of sessile benthic animal populations, ice
scour also prevents the establishment of beds of kelp and eelgrass (Zostera
marina), thus decreasing the diversity and productivity of arctic inshore
waters. Both kelp and eelgrass beds are important feeding sites for birds in
areas south of the region affected by ice scour.

Sea Ice Allows Terrestrial Predators Access to Breeding Sites

The formation of ice between the mainland and offshore islands allows the
arctic fox (Alopex lagopus) and other predators access to the islands used
by breeding birds. Foxes can become permanently established on islands
that have food sources during the period when birds are absent from the
island. Often, however, there is little to attract foxes to the islands other
than breeding birds. Because moats form around many islands before the
breeding birds arrive, foxes are primarily a problem when moat formation is
incomplete or when the breakup of ice is late. Arctic foxes are found on the
pack ice throughout the summer and thus can visit islands that are separated
from the mainland by open water but are adjacent to the pack ice.

Advantages

Sea Ice Provides a Matrix and Substrate for an Ice-associated Plankton Bloom and an Associated Under-ice Fauna

The first detailed studies on the blooms of diatoms that occur in the lower
levels of ice were done by Appollonio (1961). The importance of this bloom
in the energy budgets of arctic and subarctic seas has only recently been
realized (Alexander 1974; McRoy and Goering 1974). In areas where ice is
present throughout the year, the plankton bloom supports a population of

under-ice invertebrates. These populations have been little studied but
apparently consist primarily of copepods and amphipods (Mohr and Geiger
1968). Feeding on the invertebrates associated with the ice are two species
of fish, polar cod (Arctogadus glacialis) and arctic cod (Boreogadus saida).
Andriashev (1968) used the term cryopelagic to describe such fish, which
are found in the midwater zone but also are associated with ice during some
part of their life cycle.
The underside of multi-year ice has numerous ridges and pockets that
provide a heterogeneous environment for the under-ice fauna. This
environment is protected from disturbance from currents and wave action
by ice keels acting as barriers, which also provide shelter from predators in
the same manner as a coral reef. The overall effect of the under-ice flora
and fauna is to increase the diversity of surface waters in arctic seas by
creating an inverted benthic biota.

Sea Ice Provides Hauling Out Space for Marine Mammals

The mammals that inhabit the ice in the Chukchi and Bering seas and their
adaptations to the pack ice environment were discussed by Fay (1974).
Many of these species frequently haul out on the ice, where they provide
food in the form of feces, placentas, and carcasses.

Sea Ice Provides Roosting Sites

Ice provides a hard substrate that allows seabirds to leave the water to roost.
This allows such species as the Larus gulls, which typically roost on hard
substrates, to occur in large numbers well offshore.

Sea Ice Reduces Wind Chill

The unevenness of the upper surface of the ice reduces the speed of winds
directly over the ice, thus providing a microhabitat and reducing the amount
of wind chill for birds sitting on and next to the ice.

Sea Ice Decreases Wave Action

Ice floating on the water reduces the surface disturbance of the water.
Although swells pass through areas with much ice cover, waves do not. In
addition, surface waters on the lee side of ice floes and cakes usually have
little surface disturbance. Surface feeders may be able to locate prey more
easily because of these reductions in surface disturbance.

Specific Effects of Ice on Birds in the Western Arctic

The retreat of the pack ice each spring and the formation of new ice each
fall greatly affect a large area of the Arctic Ocean off the coast of Alaska
and much of the Bering Sea. Specific ways in which birds are affected by
ice in the western Arctic are discussed on a seasonal basis. All observations
are my own, unless otherwise stated.

Winter

Chukchi and Beaufort Seas

From late November to mid-April, ice cover of the Chukchi and Beaufort
seas is almost complete. The only areas where birds can be expected to
winter in these seas are the chronic lead systems. Such lead systems are
found off Wainwright and Point Barrow and south of the Point Hope-Cape
Thompson area (Shapiro and Burns 1975). Only the black guillemot
(Cepphus grylle) is known to regularly winter offshore from Wainwright
and Point Barrow (Gabrielson and Lincoln 1959; Nelson 1969). In the Point
Hope-Cape Thompson area, glaucous gulls (Larus hyperboreus), the
common murre (Uria aalge), and the thick-billed murre (U. lomvia) occur
throughout the winter (Swartz 1967). It is likely that black guillemots are
also found in this area.
The lack of chronic lead systems in the Beaufort Sea precludes the presence
of wintering seabirds. The one species that may be found wintering in the
Beaufort is the Ross' gull (Rhodostethia rosea). Ross' gull is believed to
winter primarily in the Arctic Ocean (Bailey 1948). The number of
sightings that have been obtained in both the eastern and western Arctic
indicate that the species may winter over much of the Arctic Ocean. It may
thus be expected to occur in both the Chukchi and Beaufort seas during
winter.

Ice cover—not prey abundance—plays the major role in severely limiting
bird numbers in the Arctic Ocean in winter. Prey is known to be abundant in
parts of the Arctic Ocean during the period of ice cover. In the Chukchi Sea,
Eskimos fishing through the ice can catch 23 kg of arctic cod per person per
day (D.C. Foote, unpublished data). Eskimos jig for the fish at considerable
depths, and the cod do not appear to be as common directly below the ice as
they are in summer. The effects of new ice (which forms on the underside
of the ice during the winter) on the under-ice fauna are not known. The
abundance of amphipods in ice-covered waters in winter is demonstrated by
the experience of the Greeley Expedition in the eastern arctic. They
discovered that any scrap of food thrown into a lead was quickly consumed
by amphipods. Nets were made to catch the amphipods and the availability
of this food source played a major part in the survival of the expedition
(Schmitt 1965).
Aside from the food found in leads in the ice, the only food available to
birds in the Beaufort and Chukchi seas in winter is carrion and the feces of
mammals found on the pack ice. The presence of the arctic foxes on the
pack ice during the winter demonstrates the availability of scavenging
opportunities on the ice. Arctic foxes on the pack ice live on feces and the
remains of seals killed by polar bears (Ursus maritimus). Polar bear and
seals are both common in the Beaufort and Chukchi seas in winter, but no
scavenging seabirds are found there in the winter. It was thought that the
ivory gull (Pagaphila eburnea) was associated with marine mammals
during the winter, but they are now known to winter at the Bering Sea ice
edge, where they feed on fish and crustaceans (Divoky 1976). The only
birds associated with polar bear kills in the Chukchi Sea in March are
ravens, Corvus corax (T. J. Ely, Jr., personal communication).

Bering Sea

Ice begins to cover the northern Bering Sea in November and reaches its
maximum by February, when it usually extends as far south as the edge of
the continental shelf, and covers nearly 75% of the surface of the Bering
Sea (Lisityn 1969). Coverage can vary greatly from year to year. In certain
years Bristol Bay may be completely covered and in others ice is found
only in the northern part of the Bay. Almost all ice in the Bering Sea is first-

year ice. This ice tends to be flat on the top and underside and in general
lacks the extensive keels and pressure ridges found on multi-year ice.
The Bering Sea ice has a number of large-scale features of importance to
birds. The "front" is a zone of ice south of the consolidated pack that is
composed of small floes, ice pans, and brash ice. This zone is prevented
from forming large floes by the action of swells from the open water to the
south. The front continually changes in width. When winds are from the
south, it is compressed into a narrow band; when winds are from the north,
it is a broad zone composed of bands of ice interspersed with open water.
Polynias (areas of open water) are found immediately south of the large
islands in the northern Bering Sea. They are formed by the southward
movement of ice caused by the prevailing winds. This movement causes ice
to be pushed away from the south side of islands, leaving areas of open
water. Large polynias are associated with St. Lawrence, St. Matthew, and
Nunivak islands and with the south side of the Seward Peninsula (Shapiro
and Burns 1975).
The most biologically active area of the Bering Sea in winter is the ice
front. Studies of primary productivity in April show that production at the
surface in the ice front is high (1.98 mg C/m3 per h). Surface waters directly
under the pack ice have much lower production (0.29 mg C/m3 per h), and
that in the water south of the ice is lower yet. At this time production within
the ice is very high (more than 5 mg C/m3 per h) (McRoy and Goering
1974). Because this phytoplankton bloom is trapped in the ice, it is not
available to grazers. Thus, before the spring melt the ice front is the only
area where a large quantity of phytoplankton is available to higher levels of
the marine food chain.
The winter distribution of birds in the Bering Sea correlates well with the
findings on primary productivity. Densities south of the ice and the
continental shelf average less than 10 birds/km2. At the ice front during one
cruise in March, densities exceeded 500 birds/km2. Densities at the ice front
increase from south to north; they drop in the region where the ice front
grades into more consolidated pack ice, and are less than 0.1 bird/km2 in the
consolidated pack.

The most numerous species at the ice front are common and thick-billed
murres, which constitute more than 90% of all birds seen. Irving et al.
(1970) were the first to report on the large number of murres at the ice front.
Feeding flocks of 25,000 individuals have been observed at the front, in
which densities were as high as 10,000 birds/km2. No other diving species
is common at the ice front. The parakeet auklet (Cyclorhynchus psittaculus)
is seen on most cruises, but only during a small percentage of observation
periods and always in low numbers. Black guillemots are common north of
the ice front and stragglers are occasionally seen at the front. Pigeon
guillemots (Cepphus columbus), least auklets (Aethia pusilla), and crested
auklets (A. cristatella) are irregular visitors to the front.
Surface feeding species commonly found at the ice front include the
northern fulmar (Fulmarus glacialis) and five species of gulls. The fulmar
is common south of the ice and is found only in the southern portion of the
front. Three species of Larus are found at the ice front. The most common
is the glaucous-winged gull (Larus glaucescens); the glaucous gull is less
frequently seen. The slaty-backed gull (L. schistisagus), a species that
breeds in Asia, is most common west of St. Matthew Island (McRoy et al.
1971). The black-legged kittiwake (Rissa tridactyla) is common in open
water south of the ice but is also found throughout the entire width of the
front. The ivory gull is unique in that it is found only at the ice front in
winter. In addition to these species, the fork-tailed storm-petrel
(Oceanodroma furcata) is a regular but uncommon visitor to the ice front in
winter. Densities of surface feeding species at the ice front are low when
compared to the high densities of murres, and do not regularly exceed 10
birds/km2.
The primary food consumed by birds at the ice front is pollock (Theragra
chalcogramma). An amphipod (Parathemisto libellula) and the euphausiids
are less important. Examination of the stomach contents of birds and fish
show that large feeding flocks are usually associated with schools of
pollock feeding on P. libellula and euphausiids.
The habitat of the consolidated pack in the Bering Sea is markedly different
from that at the ice front. Whereas the front is characterized by bands of ice
interspersed with open water and ice coverage rarely exceeding 4 oktas
(4/8), the consolidated pack consists primarily of large expanses of
unbroken ice. Small leads are formed by the shifting of the ice caused by

currents and wind. Ice coverage is usually 7 to 8 oktas. The southern part of
the consolidated pack, which grades into the ice front, has frequent leads.
Most of the species found at the ice front can be found in the southern part
of the consolidated pack, but murres are most common. Their numbers
decrease, however, in the more northerly pack, where leads are less
frequent. Black guillemots, in contrast, increase with increasing ice cover,
and reach their greatest abundance in the small leads constantly forming
and refreezing deep within the ice. Because they exploit this habitat, they
are dependent on the formation of lead systems. I have often seen leads a
quarter mile wide refrozen to the point where new ice covered all but a
small patch of open water; black guillemots were frequently crowded into
this open water. Before the lead closes completely the guillemots must fly
to an open lead. When winds are light and temperatures low, lead systems
fail to form as rapidly as usual, and when they do they refreeze quickly,
causing a loss of the preferred habitat of wintering black guillemots. A
severe winter in the White Sea in 1965-66 decreased the amount of open
water and caused an increased black guillemot mortality (Bianchi and
Karpovitsch 1969). On a windless day in March I conducted bird
observations in the Bering Sea ice where no leads or open water were
encountered. The only bird seen was a black guillemot flying over the ice.
In situations such as this, where black guillemots are prospecting for open
water, they may use the "water sky" and steam fog associated with leads as
visual aids. "Water sky" is the reflection of the dark water in the clouds over
the lead, and contrasts sharply with the "ice sky." The presence of "water
sky" allows birds to detect open water from a distance of many miles.
Aside from birds found in and near island-associated polynias, only murres
and black guillemots are regularly found on the consolidated pack ice in
winter.
The polynia associated with islands in the consolidated pack provide
refuge(s) for seabirds. Fay and Cade (1959) found the polynias south of St.
Lawrence to be most important to oldsquaws (Clangula hyemalis). King
eiders (Somateria spectabilis), common eiders (S. mollisima), and
oldsquaws are common in the St. Matthew Island polynias (McRoy et al.
1971). Because these polynias are in shallow-water areas, they provide
feeding opportunities for benthic feeding species.

Spring

Chukchi and Beaufort Seas

In April and May a lead system develops from the Bering Strait north to
Cape Lisburne and then northeast to Point Barrow. The lead is a flaw lead
that occurs between the shorefast ice and the free-floating pack. It is a
major migration route for a number of species of birds, primarily eiders.
East of Point Barrow in the Beaufort Sea, no similar well-defined large lead
exists. Consequently, there is a greater chance of bird mortality occurring in
the Beaufort Sea than in the Chukchi Sea because the early migrants are
unable to find open water. In 1960, 10% of all the king eiders that migrate
through the Beaufort Sea died during a late freeze (Barry 1968). Additional
records of eider mortality due to late breakup or sudden freezes were
presented by Palmer (1976).
In late May, rivers that empty into the northern Chukchi and Beaufort seas
begin to flow. The shorefast ice is still present at this time and the rivers
flow over the ice. For large rivers, such as the Colville and the
Sagavanirktok, the area of ice covered by water is considerable. Openings
in the ice develop sometime after the river runoff starts and the river water
drains through the ice.
This river overflow plays an important role in the breeding biology of
certain island nesting species, since the overflow surrounds islands and
prevents arctic foxes from reaching the islands. The overflow also allows
birds to sit in the water near breeding sites. It is not known whether river
overflow contains prey items available to birds. After the overflow drains
through the ice, the shorefast ice that has been covered with river overflow
decomposes quickly, and patches of open water occur early in areas just
seaward of major river deltas. For this reason the largest breeding colonies
on barrier islands in the northern Chukchi and Beaufort seas are all found
near the mouths of large rivers. Islands away from rivers become isolated
from the pack ice by moats, which are caused by the absorption of solar
radiation by the islands and the melting of the ice immediately adjacent to
them. Moat formation is not as predictable and uniform as river overflow.

Bering Sea

When the ice in the Bering Sea begins to melt in April, the edge of the pack
does not recede northward as is frequently thought. Rather, there is a
general decomposition of ice throughout the pack. The leads that are
constantly forming in the ice no longer freeze. As melt continues and ice
becomes rotten, leads form with increasing frequency. This manner of ice
decomposition is important to birds. The leads that form deep in the pack
ice provide feeding and roosting areas near the large seabird colonies found
north of the ice edge, and are used by certain tundra-nesting ocean migrants
such as eiders, red phalaropes (Phalaropus fulicarius), and jaegers
(Stercorarius spp.). If ice decomposition is retarded by persistent low
temperatures, the initiation of breeding may be delayed at northern Bering
Sea colonies and for some tundra species.
At the time of decomposition the large standing stock of phytoplankton
present in the pack ice is released into the water. No information is
available on fish and invertebrate populations that are associated with the
decomposing ice. The quantity of organic carbon released is considerable,
although it is not known what fish or invertebrate populations are supported
by this plankton as soon as it is released. For birds breeding in areas where
ice is present in the initial stages of breeding, the phytoplankton released by
the disintegrating ice could play an important part in the birds' energy
budgets.

Summer

Chukchi and Beaufort Seas

In the northern Chukchi and Beaufort seas the nearshore marine
environment is dominated by sea ice in June and July. In June the coastal
areas are characterized by a snow-free tundra teeming with nesting
waterfowl and shorebirds next to an expanse of sea ice almost completely
devoid of bird life. In areas where river outflow does not occur, the use of
nearshore waters usually begins when a moat forms along the shoreline.
Amphipods and other invertebrates are found in this moat, especially at
stream mouths. Limited but regular use of the moat occurs, primarily by
loons (Gavia spp.), oldsquaws, and arctic terns (Sterna paradisaea).

As the snow on top of the shorefast ice begins to melt, ponds form on top of
the ice. As melt proceeds, these melt ponds merge into long, parallel
channels and may cover well over 50% of the ice surface. Only when thaw
holes form and the melt ponds are connected to the water under the ice is
food present in the channels. Amphipods are then seen swimming in these
channels. Bird use of these channels is not extensive.
It is usually late July before the nearshore ice begins its rapid
decomposition. Ice in the lagoons is the first to melt. Ice seaward of the
barrier islands decomposes more slowly because of the presence of keels
and pressure ridges. As the ice melts, the in-ice algal bloom is released into
the water. These algae are important because they provide at least 25 to
30% of the productivity in coastal waters and allow the biological growing
season to begin before the open-water plankton bloom occurs (Alexander
1974). In nearshore areas close to Barrow, large populations of mysids and
amphipods are associated with the decomposing ice. At least in certain
areas, these ice-associated zooplankton populations are a major food source
for nearshore migrants, especially red phalaropes, arctic terns, and Sabine's
gulls (Xema sabini).
The effects of ice scour on the shoreline and the nearshore bottom of the
Chukchi and Beaufort seas is demonstrated by the absence of sessile
benthic fauna and flora. The effect this absence has on birds is seen in the
feeding habits of nearshore birds. Oldsquaws and eiders, which frequently
feed on molluscs, feed instead on motile benthos species such as mysids,
amphipods, and isopods. The emperor goose (Philacte canagica) is absent
from the northern Chukchi and Beaufort seas, apparently due to the absence
of eelgrass beds. Ice scour is the major cause of the absence of eelgrass in
northern Alaska (C. P. McRoy, personal communication).
The offshore ice in the Chukchi decomposes more rapidly than that in the
Beaufort, largely because Bering Sea water enters the Chukchi through the
Bering Strait (Coachman and Barnes 1961). By late July the Chukchi is
usually ice free as far north as Icy Cape. In the Beaufort, however, ice
decomposition occurs slowly through June and July, and only in August
does a definite strip of open water develop between the shore and the edge
of the pack ice. The amount of open water varies greatly from year to year.
In certain years the Beaufort is not navigable due to the lack of open water.

Aerial censusing in June and July shows that bird densities on the offshore
ice are extremely low. In August and September, when shipboard censusing
can be conducted, densities on the pack ice in both seas are about 10
birds/km2. Unlike the Bering Sea, where densities south of the ice are much
less than on the ice, bird densities south of the ice in the Beaufort and
Chukchi seas are slightly higher in the open water south of the ice,
averaging about 20 birds/km2. In the Chukchi the principal species
encountered on the ice are the black-legged kittiwake and the thick-billed
murre. In the Beaufort, red phalaropes, oldsquaws, and glaucous gulls are
the most common species.
Numerous arctic cod are associated with the underside of the summer pack
ice. Shipboard censusing in the ice is complicated when cod are stranded on
ice floes, as the ice shifts under the weight of the ship. Gulls, arctic terns,
and jaegers gather behind the ship to feed on these fish; mixed flocks of
more than 100 birds are common. In the absence of a ship to provide the
disturbance needed to make large numbers of cod available, these birds are
dependent on locating the fish in the surface waters next to ice floes.
Because cod frequently swim over underwater ice shelves they are highly
visible from above and should be easily accessible to aerial feeders.

Fall

Chukchi and Beaufort Seas

By the time ice formation begins in late September or early October, most
seabirds have left the Arctic on their southward migration. The principal
exception is the oldsquaw, which does not begin its migration until
September. Some oldsquaws remain in nearshore waters until they are
driven out by the formation of new ice. In contrast to the spring mortality,
there are few records of extensive bird mortality in the fall due to lack of
open water. One instance was reported for 1975, when nearshore waters
froze early and flightless eiders were seen sitting on the ice near Pt. Lay in
the Chukchi Sea. The birds were in a weakened condition, apparently due to
their inability to obtain food (W. J. Wiseman, personal communication).
In the offshore waters the species associated with the pack ice in September
are the same as those in August. In late September, however, ivory and

Ross' gulls become the most common species at the ice edge in the
Chukchi. Glaucous gulls and black guillemots are also associated with the
advancing ice edge (Watson and Divoky 1972). Except for the Ross' gull,
which apparently winters in the arctic basin, these species remain with the
ice as it advances into the Bering Sea.

Bering Sea

Little is known about bird distribution in the Bering Sea during ice
formation because cruises in rapidly forming ice are potentially hazardous.
It is not known if the large numbers of birds found at the ice edge in March
are present in December and January.

Discussion

The principal effect of the arctic pack ice is to lower biological productivity
and bird densities in the areas it covers. Unlike the antarctic pack ice, which
supports a large biomass of pagophilic species, the number of pagophilic
species supported by the arctic pack ice is small. Only the ivory gull, Ross'
gull, and black guillemot have specific adaptations to the ice environment.
The Ross' gull and guillemot winter in the pack ice, and the ivory gull is
associated with ice throughout the year. The total biomass of these species
is low. Other species which are regularly associated with the arctic pack,
such as murres and black-legged kittiwakes, are also found in large numbers
away from the ice. In addition, these species are usually associated with ice
for limited periods during the year—murres primarily in winter and spring
and kittiwakes primarily in summer.
The difference in the antarctic and arctic pack ice systems is largely due to
the antarctic pack ice being surrounded by ocean, whereas the arctic pack
ice is, in general, surrounded by land. The high productivity associated with
the antarctic pack ice is due primarily to the mixing that occurs at the edge
of the pack ice. There is little opportunity for mixing to occur next to the
arctic pack ice, except where it is next to large expanses of boreal waters.
This occurs in the Bering Sea in winter and spring, in the North Atlantic,
and to a minor extent in the Chukchi Sea in summer and fall (Dunbar 1968).
The limited geographic range and seasonal nature of high productivity at

the arctic pack ice edge has been a major factor in preventing a well-
developed pagophilic avifauna.
The importance of the in-ice algal bloom and its associated under-ice fauna
is not yet clear. It is probably most important in areas such as the Beaufort
Sea, where productivity in the water column is low. Although considerable
numbers of seabirds are regularly found in the summer pack ice feeding on
arctic cod and zooplankton associated with the ice, bird densities south of
the ice are usually greater than those in the ice. The only species that appear
to depend on the ice-associated fauna for much of their food are the three
pagophilic species mentioned above.

References

Alexander, V. 1974. Primary productivity regimes of the
nearshore Beaufort Sea, with reference to potential roles of
ice biota. Pages 609-632 in J. C. Reed and J. E. Sater, eds.
The coast and shelf of the Beaufort Sea. Arctic Institute of
North America, Arlington, Virginia.
Andriashev, A. P. 1968. The problem of the life community
associated with the antarctic fast ice. Pages 147-155 in R. I.
Currie, ed. Symposium on antarctic oceanography. Scott
Polar Research Institute, Cambridge.
Appollonio, S. 1961. The chlorophyll content of arctic sea ice.
Arctic 14:197-200.
Bailey, A. M. 1948. Birds of arctic Alaska. Colo. Mus. Nat. Hist.
Popular Ser. 8. 317 pp.
Barry, T. W. 1968. Observations on natural mortality and native
use of eider ducks along the Beaufort Sea coast. Can. Field-
Nat. 82(2): 140-144.
Bianchi, V. V., and V. N. Karpovitsch. 1969. The influence of
abnormal ice-cover of the White Sea and Murman in 1966
upon birds and mammals. (In Russian, English summary.)
Zool. Zh. 48(6):871-875.

Bunt, J. S. 1963. Diatoms of antarctic sea ice as agents of primary
production. Nature (Lond.) 199:1255-1257.
Coachman, L. K., and C. A. Barnes. 1961. The contribution of
Bering Sea water to the Arctic Ocean. Arctic 15:147-161.
Divoky, G. J. 1976. The pelagic feeding habits of Ivory and Ross'
Gulls. Condor 78:85-90.
Dunbar, M. J. 1968. Ecological development in polar regions: a
study in evolution. Prentice-Hall, Englewood Cliffs, N.J.
119 pp.
Fay, F. H. 1974. The role of ice in the ecology of marine
mammals of the Bering Sea. Pages 383-399 in D. W. Hood
and E. J. Kelly, eds. Oceanography of the Bering Sea. Univ.
Alaska Inst. Mar. Sci. Occas. Publ. 2.
Fay, F. H., and T. J. Cade. 1959. An ecological analysis of the
avifauna of St. Lawrence Island, Alaska. Univ. Calif. Publ.
Zool. 63:73-150.
Gabrielson, I. N., and F. C. Lincoln. 1959. The birds of Alaska.
The Stackpole Company, Harrisburg, Pennsylvania, and
Wildlife Management Institute, Washington, D.C. 922 pp.
Irving, L., C. P. McRoy, and J. J. Burns. 1970. Birds observed
during a cruise in the ice-covered Bering Sea in March 1968.
Condor 72:110-112.
Lisityn, A. P. 1969. Recent sedimentation in the Bering Sea
(Transl. from Russian.) Israel Program for Scientific
Translations, Jerusalem. 614 pp.
McRoy, C. P., and S. R. Goering. 1974. The influence of ice on
the primary productivity of the Bering Sea. Pages 403-421
in D. W. Hood and E. J. Kelly, eds. Oceanography of the
Bering Sea. Univ. Alaska Inst. Mar. Sci. Occas. Publ. 2.
McRoy, C. P., S. W. Stoker, G. E. Hall, and E. Muktoyuk. 1971.
Winter observations of mammals and birds, St. Matthew
Island. Arctic 24:63-65.

Mohr, J. L., and S. R. Geiger. 1968. Arctic Basin faunal precis-
animals taken mainly from arctic drifting stations and their
significance for biogeography and water-mass recognition.
Pages 297-313 in J. E. Sater, coordinator. Arctic drifting
stations. Arctic Institute of North America.
Nelson, R. K. 1969. Hunters of the northern ice. University of
Chicago Press, Chicago, Ill. 429 pp.
Palmer, R. S. 1976. Handbook of North American birds. Vol. 3.
Yale University Press, New Haven, Conn. 560 pp.
Schmitt, W. L. 1965. Crustaceans. University of Michigan Press,
Ann Arbor. 204 pp.
Shapiro, L. H., and J. J. Burns. 1975. Major late-winter features
of ice in northern Bering and Chukchi seas as determined
from satellite imagery. Univ. Alaska Geophys. Inst. Rep. 75-
78.
Swartz, L. G. 1967. Distribution and movements of birds in the
Bering and Chukchi seas. Pacific Sci. 21:332-347.
Watson, G. E., and G. J. Divoky. 1972. Pelagic bird and mammal
observations in the eastern Chukchi Sea, early fall 1970.
U.S. Coast Guard Oceanogr. Rep. 50:111-172.

FOOTNOTES:

[1] Present address: Point Reyes Bird Observatory, 4990 State Route 1, Stinson
Beach, California 94970.

STATUS OF MARINE BIRD POPULATIONS

Distribution and Status of Marine Birds Breeding Along the Coasts of
the Chukchi and Bering Seas

by
James C. Bartonek[2]
U.S. Fish and Wildlife Service
Fairbanks, Alaska
and
Spencer G. Sealy
University of Manitoba
Winnipeg, Manitoba, Canada

Abstract

The Alaska coast fronting on the Chukchi and Bering seas,
exclusive of the Aleutian Islands, supports seven complexes of
marine bird colonies numbering more than 1 million birds each,
nine colonies of 100,000 to almost 1 million birds, and many
smaller colonies. Colonies are found on most headlands and
islands and are dominated numerically by alcids and kittiwakes
(Rissa sp.). Estuarine habitats (mainly the lowlands of northern
Seward Peninsula, Yukon-Kuskokwim delta, and the north side of
the Alaska Peninsula) are extremely important for breeding and
migrating marine waterfowl, shorebirds, gulls (Larus sp.), and
terns (Sterna sp.). Information on population size and distribution
of breeding marine birds within this area is extensive for only a
few of the more heavily hunted species of waterfowl. Except for
the intensive and systematic censusing of a few colonies in this
region, population data on cliff-, burrow-, and crevice-nesting
birds are such that all but gross changes in numbers may go
unnoticed, and if noticed they could not be measured.
Habitats for breeding marine birds are found along much of the 4,100-km coastline
of Alaska that fronts on the Chukchi and Bering seas. Seasonal sea ice and an
extensive outer continental shelf are dominant features that contribute to the

productivity of these marine waters, which sustain populations of fishes, birds, and
mammals that are of considerable and diverse values to man (Kelley and Hood
1974).
Our purpose in this paper is to describe the distribution, abundance, and relative
status of some of the nearly 100 species of marine birds breeding within this region
and the information base from which the descriptions are derived. Although the
selection is admittedly arbitrary, we discuss mainly the colonial nesting species
because they are generally in greater jeopardy from lost breeding habitat and from
catastrophes than are the species that are widely dispersed or solitary in nesting.
Because we believe matters affecting the conservation of marine birds will be
geographically oriented, we discuss the status and distribution of breeding birds on
that basis, rather than by the more traditional taxonomic approach. We use the
terms "colony" and "colonies" somewhat loosely and interchangeably to include
any aggregation of birds of the same or different species nesting in proximity to
each other, even those on the same island or headland, although populations may be
miles apart and occupy different kinds of habitats. The nature of this paper and the
scale of our maps do not allow for detailed resolution of each colony's location (for
the most part this information is not available), but rather facilitates a general
impression of status.
Most place-names used by us are shown in Fig. 1; the others may be located by
referring to Orth's (1967) gazetteer on Alaska.

Information Base

There is no adequate catalog of marine bird colonies and other avian habitats for
the Bering-Chukchi region or for Alaska as a whole. King and Lensink (1971)
described the waterfowl populations and major lowland habitats of the State and
listed only a few of the many colonies of cliff-nesting birds. LeResche and Hinman
(1973) identified a few additional colonies, provided fragmentary information on
composition and abundance at some of these sites, and delineated areas of wetland
habitats on maps in their statewide atlas on wildlife. General and occasionally site-
specific information on the location, but rarely on population size and composition,
of colonies can be gleaned from the 321 species accounts presented by Gabrielson
and Lincoln (1959) and from the general works by Bent (1919, 1921, 1922, 1923,
1925, 1927, 1929), Dement'ev and Gladkov (1951), Dement'ev et al. (1951, 1952),
Palmer (1962), Fisher (1952), Tuck (1960), and others. The birds on the Asiatic side
of these waters, which are not treated in this paper, were described by Portenko
(1973).

Information on the status of waterfowl in the region is generally more detailed than
that for most other groups of birds because waterfowl have been the object of
systematic surveys since the late 1940's as part of the continent-wide effort to
manage populations for sport hunting. Because the emphasis of these surveys has
been directed toward the species of ducks important to hunters in the "lower 48"
States, data are not adequate to measure changes in populations for most sea ducks
and marine geese nesting in this region. These surveys have, however, enabled
biologists to delineate waterfowl habitats and make reasonable estimates of
populations for some of the more abundant and conspicuous species (King and
Lensink 1971; U.S. Fish and Wildlife Service [FWS] 1973c; U.S. National Park
Service [NPS] 1973).

Chukchi Sea Coast

A disproportionate percentage of ornithological investigations in arctic Alaska have
centered about Barrow, where ornithologists were attracted because of the
propensity of vagrant birds to collect there and because of the above average
facilities, conveniences, and transportation afforded first by the whaling station,
then by the military, and later by a research laboratory. Recent petroleum
development near Prudhoe Bay has resulted in a somewhat commensal eastward
shift in ornithological studies.
Bailey (1948), Gabrielson and Lincoln (1959), and Pitelka (1974) reviewed much
of the published information on arctic avifauna, including that of the Chukchi coast.
Selkregg [1975] mapped various avian habitats, ascribed either relative or absolute
values for the population size of certain groups of birds, and included a selected
bibliography that did not entirely duplicate those provided by the other reviewers.
Watson and Divoky (1975) described the avifauna of Alaska's Beaufort Sea coast,
which is much the same as that of the Chukchi coast from Point Barrow south to
Cape Lisburne (both coasts are of low relief).
Intensive studies near Barrow have done much to characterize the behavior,
productivity, and ecological requirements of calidridine sandpipers (Pitelka 1959;
Pitelka et al. 1974; Holmes 1970, 1971) and, to partly explain the cyclical
relationships between jaegers (Stercorarius spp.) and their prey (e.g., Pitelka et al.
1955; Maher 1974). Quantitative estimates of certain bird populations at Cape
Thompson (Swartz 1966; Williamson et al. 1966), Little Diomede (Kenyon and
Brooks 1960), and on the coastal lowlands of the Seward Peninsula (King and
Lensink 1971; U.S. NPS 1973), and for black guillemots (Cepphus grylle)
throughout the region (Divoky et al. 1974) are among the best data on status of
marine birds for any locality in Alaska. Grinnell (1900a) described the birds he
observed in the Kotzebue Sound area.

Fig. 1. Place-names in the region of the Chukchi and
Bering seas.

Cursory aerial surveys conducted by J. C. Bartonek, J. G. King, and D. R. Cline
(U.S. FWS 1973a; U.S. NPS 1973; this paper) in 1972 and 1973 provided
information on the location and relative size of most, if not all, colonies of cliff-
nesting marine birds between Point Barrow and the Bering Strait, including those at
Cape Lisburne, at Motherhood Point, Nine-mile Point, Cape Deceit, Towalevic
Point, Sullivan Bluff, all on the northern base of the Seward Peninsula, and at
Fairway Rock. The relative size of populations of most species was probably

underestimated because the burrow-and crevice-nesting species were largely
unseen.

Bering Sea

Aside from work by Gabrielson and Lincoln (1959) and the early but
understandably incomplete accounts by Nelson (1883, 1887) and Turner (1886), no
comprehensive description of the avifauna of the Alaskan coast of the Bering Sea
exists. Many studies adequately describe local avifauna, and some of them are
exemplary assessments of the status of populations.
Most of the coastline suitable for cliff-nesting marine birds and most of the smaller
nearshore islands from the Bering Strait south to the tip of the Alaska Peninsula
were reconnoitered piecemeal from aircraft between 1970 and 1973 by J. C.
Bartonek, J. G. King, D. R. Cline, C. D. Evans, and M. L. Plenert (U.S. FWS
1973a, 1973b; this paper). In late June 1973 Bartonek, Cline, and Plenert made
brief reconnaissances on foot of King, Besboro, and Shaiak islands. Bartonek and J.
G. Divoky, traveling by boat and occasionally on foot, reconnoitered colonies at
Cape Seniavin, a portion of the Walrus Islands group, Shaiak Island, and the
coastline from Cape Peirce around Cape Newenham to Security Cove (U.S. FWS
1973a, 1973b; this paper). Although these cursory surveys (especially those from
aircraft) tended to identify nesting sites of cliff-nesting birds while missing sites
used by burrow-and crevice-nesting species, information was obtained on the
location and relative size of many previously unreported colonies.
The mainland and island colonies in Norton Sound have received little notice in the
published literature. Bailey (1943, 1948), although working mainly at Little
Diomede and in Arctic and Lopp lagoons on the north side of the Seward Peninsula,
mentioned the birds at Wales Mountain and Tin City. Nelson (1883, 1887) traveled
throughout the region studying the avifauna and the anthropology of Eskimos.
Grinnell (1900b) at Nome, McGregor (1902) along the Koyuk River, Hersey (1917)
and Turner (1886) near St. Michael, and Cade (1952) at Sledge Island provide
fragmentary examples of the area's marine bird populations. Colonies at King,
Besboro, Egg, and Sledge islands, near York Mountains, and at Bluff were
described in proposals for new National Wildlife Refuges (U.S. FWS 1973a).
Sealy et al. (1971) reviewed the literature and discussed the various zoogeographic
relationships among the avifauna of St. Lawrence Island. Fay and Cade (1959)
estimated numbers and biomass of all birds on St. Lawrence Island but did not
identify locations and sizes of particular populations; consequently, replication of
their estimates is precluded. An exemplary study by Bédard (1969) identified the
locations and sizes of all populations of crested auklets (Aethia cristatella), least
auklets (A. pusilla), and parakeet auklets (Cyclorrhynchus psittacula) on the island.

Sealy (1973) identified breeding sites of horned puffins (Fratercula corniculata)
there and throughout the species' range. Thompson (1967) listed the birds observed
at Northeast Cape and on nearby Punuk Islands.
Annotated accounts have been published on the breeding avifauna of St. Matthew,
Hall, and Pinnacle islands by Elliott (1882), Hanna (1917), Bent (1919), and
Gabrielson and Lincoln (1959). Klein (1959) presented quantitative data on the
birds he observed incidental to his study of reindeer (Rangifer tarandus).
The avifauna of the Yukon-Kuskokwim delta, which is rich both in numbers and
diversity, has been treated extensively in the literature. Nelson (1883, 1887), Turner
(1886), Conover (1926), Brandt (1943), Gabrielson and Lincoln (1959), Williamson
(1957), Kessel et al. (1964), Harris (1966), Dau (1972), and Holmes and Black
(1973) all described the avifauna in the same general area of the delta, i.e., the
eroding portion in the general vicinity of Hooper and Hazen bays. The avifauna of
the aggrading portion of the Yukon delta and of the Kuskokwim's mouth have not
been accorded similar attention. Populations of waterfowl nesting on the delta and
their wintering affinities were described by King and Lensink (1971) and U.S. FWS
(1973c).
Studies of particular species of marine birds on the delta (again, all in the general
vicinity of Hooper and Hazen bays) were reported by Hansen and Nelson (1957)
and Shepherd (1960) for black brant (Branta bernicla), by Headley (1967) and
Eisenhauer and Kirkpatrick (1977) for emperor geese (Anser canagica), by Dau
(1974) and Mickelson (1975) for spectacled eiders (Somateria fischeri), by Petersen
(1976) for red-throated loons (Gavia stellata), and by Holmes (1970, 1971, 1972)
for dunlins (Calidris alpina) and western sandpipers (C. mauri).
Birds of Nunivak Island were reported by Swarth (1934), but the importance of the
island to marine birds was not put into proper perspective until the Nunivak
National Wildlife Refuge was evaluated for designation as a wilderness area (U.S.
FWS 1972).
The Pribilof Islands have served as a focal point for ornithological investigations of
the Bering Sea in much the same way that Barrow has for the Arctic. The avifauna
of the Pribilofs has been described by Coues (1874), Elliott (1882), Palmer (1899),
Hanna (1918), Preble and McAtee (1923), Gabrielson and Lincoln (1959), Kenyon
and Phillips (1965), and a host of others that mainly added new species to the
record list. Although most of these ornithologists marveled at the numbers of birds,
information is lacking from which most changes in populations can be noted. (An
exception is the record of common and thick-billed murres, Uria aalge and U.
lomvia, which formerly nested in such abundance on Walrus Island that annually
several tons of eggs were gathered for consumption by residents of the islands
[Palmer 1899], but were greatly reduced in numbers by the summer of 1973, when

J. C. Bartonek, J. G. King, G. J. Divoky, and D. T. Montgomery observed only a
few thousand murres on a small portion of the island. Most of the suitable nesting
sites, especially the flat areas often used by common murres, were occupied by
Steller's sea lions, Eumetopias jubata, which, apparently because of reduced
hunting pressure, occupied the island and displaced the murres.)
For some unexplained reason the numerous and large marine bird colonies along
the north side of Bristol Bay appear to have been largely overlooked until recent
years (Bartonek and Gibson 1972). Gabrielson and Lincoln (1959) summarized the
few observations by Osgood (1904) and Turner (1886) in this area, but obviously
were unaware that, in aggregate, these colonies rival those of the Pribilofs. Dick
and Dick (1971) made an exemplary study of marine birds and their numbers at
Cape Peirce and on nearby Shaiak Island. Murie (1959) provided annotated
remarks on marine birds of Amak Island, but not of nearby Sealion Rocks.

Status and Distribution

Seven groups of colonies of cliff-, burrow-, and crevice-nesting birds are found on
the headlands and islands in the coastal region, each numbering more than 1 million
birds; nine colonies range downward to 100,000 birds; and a host of others range
downward to 1,000 birds (Fig. 2). Un-estimated numbers of other marine birds nest
on the lowlands about Kotzebue Sound, the Yukon-Kuskokwim delta, and Bristol
Bay, but are not shown in Fig. 2. The occurrence at colonies of 20 of the nearly 100
species of marine birds is shown in Fig. 3; their relative numbers at these sites are
not shown because data are generally lacking.

Fig. 2. Relative numbers of marine birds at colonies in
different localities, without regard to species
composition or breeding status.

Fig. 3. Location of known breeding populations of some
marine bird species without regard to size of
population.

Chukchi Sea

The largest colonies of seabirds in the Chukchi Sea are those on Little Diomede
Island, Cape Lisburne, Cape Thompson, and Fairway Rock. Smaller colonies are in
Kotzebue Sound along the northern base of the Seward Peninsula. These colonies
are largely dominated by thick-billed and common murres and black-legged
kittiwakes (Rissa tridactyla) and on the islands in the Bering Strait also the crested,
least, and parakeet auklets. Horned puffins, tufted puffins (Lunda cirrhata), pelagic
cormorants (Phalacrocorax pelagicus), and glaucous gulls (Larus hyperboreus)
make up the remaining majority. For the whole area there are probably fewer than a
hundred birds each of black guillemots and pigeon guillemots (Cepphus columba)

occupying colonies. Dovekies (Alle alle) are occasionally sighted in this area, but
only as stragglers from their normal range.
Part of the mystery surrounding the nesting location of Kittlitz's murrelet
(Brachyramphus brevirostris) was solved when Thompson et al. (1966) discovered
a downy chick in the Kukpuk River drainage nearly 45 km by river from salt water.
Other nesting sites of the Kittlitz's murrelets in this region were reported for Wales
Mountain (Ford 1936; Bailey 1943, 1948) and the Cold Bay area (Bailey 1973)
(Fig. 3).
Only the colonies at Cape Thompson have been censused systematically throughout
a breeding season. During one of three years of varying census efforts, Swartz
(1966) estimated that about 400,000 birds of nine species occupied the cliffs.
Whereas the Cape Thompson colonies received considerable attention because of
Swartz's efforts, the colonies that extend along nearly 35 km of headlands
southward from, but mainly at, Cape Lisburne have received little if any attention
by either early or recent ornithologists in the Arctic, even though they support
perhaps twice the number of birds. Also perplexing is why Chamisso and Puffin
islands with their several thousand nesting horned puffins and lesser numbers of
other seabirds were designated as the Chamisso National Wildlife Refuge in the
early 1900's when none of the many larger and more species-diverse colonies in the
area received comparable recognition by and protection through refuge designation.
The lowlands on the north side of the Seward Peninsula produce fall flights of sea
ducks that average 49,200 oldsquaws (Clangula hyemalis), 51,000 eiders (mostly
common eiders, Somateria mollissima), and 26,700 scoters (mostly black scoters,
Melanitta nigra) (King and Lensink 1971). Small populations of black brant and
emperor geese breed in what outwardly appears to be excellent habitat, and King
and Lensink (1971) speculated that subsistence hunting by local Eskimos is
responsible for suppressing these populations.

Bering Sea

The largest concentration of nesting seabirds in the Bering Sea and perhaps in the
entire North Pacific is that on St. George Island. Colonies that rank somewhere
below that at St. George are along the coast from Cape Newenham to Cape Peirce,
in the Walrus Islands (Round, High, Crooked, and Summit islands, The Twins, and
Black Rock), at Cape Mohican on Nunivak Island, St. Matthew Island, Southwest
Cape of St. Lawrence Island, and King Island.
The Pribilofs have the unique distinction of being the primary nesting site of red-
legged kittiwakes (Rissa brevirostris). They are also interesting from the
zoogeographic standpoint in that they are the northernmost stronghold of red-faced

cormorants (Phalacrocorax urile); guillemots are conspicuous by their absence, and
larid gulls are conspicuously scarce nesters.
St. Matthew Island and associated Hall and Pinnacle islands, and all but Walrus
Island of the Pribilofs, are sites of nesting northern fulmars (Fulmarus glacialis).
Nesting fork-tailed or Leach's storm-petrels (Oceanodroma furcata and O.
leucorhoa) have been found nowhere in this region, although both are commonly
observed at sea and both nest throughout the Aleutians.
Most colony sites identified in Fig. 2 are dominated by common or thick-billed
murres (or both) and black-legged kittiwakes. Glaucous gulls (generally north of
the Yukon-Kuskokwim delta), glaucous-winged gulls (Larus glaucescens)
(generally to the south of the delta), and pelagic cormorants occupy almost every
rocky prominence along the entire coast (most of these sites are not shown in Figs.
2 and 3). Double-crested cormorants (Phalacrocorax auritus) nest at a few island
and inland locations in the Bristol Bay area. The small auklets are largely restricted
to islands in the Bering Sea; the parakeet auklet is the only one occasionally found
in mainland colonies.
The marine birds of the Yukon-Kuskokwim delta lowlands, although largely
uncounted, in their aggregate probably exceed the numbers at any individual site
identified in Fig. 2. This is not particularly surprising since the delta has nearly
70,000 km2 of habitat (King and Lensink 1971) in contrast to the generally small
parcels of habitat occupied at the sea-cliff and island sites.
King and Lensink (1971) estimated that fall flights of sea ducks originating on the
delta averaged 292,300 oldsquaws, 51,000 eiders (mostly common and spectacled
eiders with lesser numbers of Steller's eiders, Polysticta stelleri), and 157,000
scoters (primarily black scoters). They also estimated that half of the 150,000 black
brant and most of the 150,000 emperor geese in Alaska's fall flight originate there.
Although no counts have been made, we believe that the delta's lowlands support
easily more than half of Alaska's nesting dunlins, black turnstones (Arenaria
melanocephala), rock sandpipers (Calidris ptilocnemis), western sandpipers, and
substantial percentages of red phalaropes (Phalaropus fulicarius), northern
phalaropes (Lobipes lobatus), and red-throated loons.
The north side of the Alaska Peninsula (including the wetlands, uplands, and
estuaries) is perhaps more important to marine birds as a staging, feeding, and
resting area than as a nesting habitat. The importance of Izembek Lagoon to black
brant and emperor geese during fall and spring is a classic example. King and
Lensink (1971) estimated that the fall flight of sea ducks originating from the
Peninsula averages 53,400 oldsquaws, 1,700 eiders, and 74,400 scoters. Breeding
geese are scarce throughout the area.

Conclusions and Recommendations

Most of the major breeding habitats of marine birds in the Chukchi and Bering seas
are known, but imprecisely identified as to location and size. With few exceptions,
the populations of birds using these habitats are described only by the subjective
and ambiguous descriptors of abundance such as "abundant, common, occasional,
and rare," which makes measurement of change impossible.
We recommend that first and foremost a catalog of habitats used by birds be
developed to aid resource administrators, developers, and biologists (all of whom
should be "conservationists") in identifying critical habitats. We believe that such a
catalog would preclude many problems because birds and their habitats could be
considered at the planning stage rather than only at the operational stage. Such a
catalog would also be useful to students of ornithology who are seeking locations
suitable for particular studies.
Nowhere in this region have studies of marine birds been of sufficient duration to
enable changes in populations (from whatever cause) to be characterized. Since
some species of marine bird are known not to breed before at least 3 or more years
of age, meaningful information on survival and recruitment in populations cannot
be obtained by studies of less than 10 years. We therefore recommend that long-
term studies be initiated at as many places as possible, but at least at one site on the
Yukon-Kuskokwim delta; at a mainland colony site that has predominantly murres,
kittiwakes, puffins, and cormorants; and at an island site that also has small auklets.
Although the nesting distribution of the Kittlitz's murrelet remains an enigma, we
regard it less of a conservation issue and more of an ornithological challenge.
Consideration of logistics and support facilities must, of course, be included in the
site selection process. Most of the areas suggested for these studies also merit
recognition and protection by being designated as a National Wildlife Refuge, a
National Park or Monument, or a State Game Sanctuary.

References

Bailey, A. M. 1943. The birds of Cape Prince of Wales, Alaska. Proc.
Colo. Mus. Nat. Hist. 18. 113 pp.
Bailey, A. M. 1948. Birds of arctic Alaska. Colo. Mus. Nat. Hist.
Popular Ser. 8. 317 pp.
Bailey, E. P. 1973. Discovery of a Kittlitz's murrelet nest. Condor
75(4):457.

Bartonek, J. C., and D. D Gibson. 1972. Summer distribution of pelagic
birds in Bristol Bay, Alaska. Condor 74(4):416-422.
Bédard, J. 1969. The nesting of the least, crested, and parakeet auklets
around St. Lawrence Island, Alaska. Can. J. Zool. 47(5):1025-
1050.
Bent, A. C. 1919. Life histories of North American diving birds. U.S.
Natl. Mus. Bull. 107. 245 pp.
Bent, A. C. 1921. Life histories of North American gulls and terns. U.S.
Natl. Mus. Bull. 113. 345 pp.
Bent, A. C. 1922. Life histories of North American petrels, pelicans,
and their allies. U.S. Natl. Mus. Bull. 121. 343 pp.
Bent, A. C. 1923. Life histories of North American wild fowl. Part I.
U.S. Natl. Mus. Bull. 126. 250 pp.
Bent, A. C. 1925. Life histories of North American wild fowl. Part II.
U.S. Natl. Mus. Bull. 130. 311 pp.
Bent, A. C. 1927. Life histories of North American shore birds. Part I.
U.S. Natl. Mus. Bull. 142. 359 pp.
Bent, A. C. 1929. Life histories of North American shore birds. Part II.
U.S. Natl. Mus. Bull. 146. 340 pp.
Brandt, H. 1943. Alaska bird trails. Bird Research Foundation,
Cleveland, Ohio. 464 pp.
Cade, T. J. 1952. Note on the birds of Sledge Island, Bering Sea,
Alaska. Condor 52(1):51-54.
Conover, H. B. 1926. Game birds of the Hooper Bay region, Alaska.
Auk 43(2):162-180, 43(3):308-318.
Coues, E. 1874. Ornithology of the Prybilov Islands. Pages 168-212 in
H. W. Elliott, Report on the Prybilov Group, or Seal Islands of
Alaska. U.S. Treasury Department, Washington, D.C.
Dau, C. 1972. Observations on the spring migration of birds at Old
Kashunuk Village, Alaska. Univ. Alaska, Dep. Wildl. Fish.,
Fairbanks. 54 pp. (Unpublished report)
Dau, C. 1974. Nesting biology of the spectacled eider Somateria
fischeri (Brandt) on the Yukon-Kuskokwim delta, Alaska. M. S.
Thesis. Univ. of Alaska, Fairbanks. 72 pp.

Dement'ev, G. P., and N. A. Gladkov. 1951. Birds of the Soviet Union.
Vol. 1. (Transl. from Russian.) Israel Progr. Sci. Transl., 1966. 705
pp.
Dement'ev, G. P., N. A. Gladkov, Yu. A. Isakov, N. N. Kartashev, S. V.
Kirikov, A. V. Mikheev, and E. S. Prushenko. 1952. Birds of the
Soviet Union. Vol. 4. (Transl. from Russian.) Israel Progr. Sci.
Transl., 1967. 683 pp.
Dement'ev, G. P., N. A. Gladkov, and E. P. Spageburg. 1951. Birds of
the Soviet Union. Vol. 2. (Transl. from Russian.) Israel Progr. Sci.
Transl., 1968. 553 pp.
Dick, M. H., and L. S. Dick. 1971. The natural history of Cape Peirce
and Nanvak Bay, Cape Newenham Natl. Wildl. Refuge, Alaska.
U.S. Bureau Sport Fisheries and Wildlife, Bethel, Alaska. 78 pp.
Divoky, G. J., G. E. Watson, and J. C. Bartonek. 1974. Breeding of the
black guillemot in northern Alaska. Condor 76(3):339-343.
Eisenhauer, D. I., and C. M. Kirkpatrick. 1977. Ecology of the emperor
goose in Alaska. Wildl. Monogr. 57. 62 pp.
Elliott, H. W. 1882. Seal-islands of Alaska. U.S. Comm. Fish Fish.
Spec. Bull. 176, Sect. IX, Monogr. A. 176 pp.
Fay, F. H., and T. J. Cade. 1959. An ecological analysis of the avifauna
of St. Lawrence Island, Alaska. Univ. Calif. Publ. Zool. 63:73-150.
Fisher, J. 1952. The fulmar. N. M. N. Collins, London. 496 pp.
Ford, E. R. 1936. Kittlitz's murrelet breeding at Wales, Alaska. Auk
51:214-215.
Gabrielson, I. N., and F. C. Lincoln. 1959. The birds of Alaska. The
Stackpole Co., Harrisburg, Pennsylvania, and Wildlife
Management Institute of North America, Washington, D.C. 992
pp.
Grinnell, J. 1900a. Birds of the Kotzebue Sound region, Alaska. Pac.
Coast Avifauna 1. 80 pp.
Grinnell, J. 1900b. Notes on some birds of Cape Nome, Alaska. Condor
2(5):112-115.
Hanna, G. D. 1917. The summer birds of the St. Matthew Island Bird
Reservation. Auk 34(4):403-410.

Hanna, G. D. 1918. Check list of birds of the Pribilof Islands, Alaska,
with names of persons first recording the species from the islands.
Pages 105-107 in W. T. Bower, ed., Report of U.S. Commissioner
of Fisheries. Bureau of Fisheries Document 872.
Hansen, H. A., and U. C. Nelson. 1957. Brant of the Bering Sea—
migration and mortality. Trans. N. Am. Wildl. Nat. Resour. Conf.
22:237-256.
Harris, S. W. 1966. Summer birds of the lower Kashunuk River, Yukon-
Kuskokwim delta, Alaska. Murrelet 47(3):57-65.
Headley, P. C. 1967. Waterfowl. Ecology of the emperor goose. Alaska
Dep. Fish Game Small Furbearer Invest. 8:1-25.
Hersey, F. S. 1917. The present abundance of birds in the vicinity of
Fort St. Michael, Alaska. Auk 34(2):147-159.
Holmes, R. T. 1970. Differences in population density, territoriality, and
food supply of dunlin on arctic and subarctic tundra. Pages 303-
319 in A. Watson, ed., Animal populations in relation to their food
resources. Br. Ecol. Soc. Symp. 10.
Holmes, R. T. 1971. Density habitat and mating system of the western
sandpiper (Calidris mauri). Oecologia 7(2):191-208.
Holmes, R. T. 1972. Ecological factors influencing the breeding season
schedule of western sandpipers (Calidris mauri) in sub-arctic
Alaska. Am. Midl. Nat. 87(2):472-491.
Holmes, R. T., and C. P. Black. 1973. Ecological distribution of birds in
the Kolomak River-Askinuk Mountain region, Yukon-Kuskokwim
delta, Alaska. Condor 75(2):150-163.
Kelley, E. J., and D. W. Hood, eds. 1974. PROBES: a prospectus on
processes and resources of the Bering Sea shelf, 1975-1985. Univ.
Alaska, Inst. Mar. Sci. Publ. Inf. Bull. 75-1. 71 pp.
Kenyon, K. W., and J. W. Brooks. 1960. Birds of Little Diomede Island,
Alaska. Condor 62(6):457-463.
Kenyon, K. W., and R. E. Phillips. 1965. Birds from the Pribilof Islands
and vicinity. Auk 82(4):624-635.
Kessel, B., H. K. Springer, and C. M. White. 1964. June birds of the
Kolomak River, Yukon-Kuskokwim delta, Alaska. Murrelet
45(3):37-47.

King, J. G., and C. J. Lensink. 1971. An evaluation of Alaskan habitat
for migratory birds. U.S. Bur. Sport Fish. Wildl., Washington, D.C.
46 pp. (Unpublished administrative report)
Klein, D. R. 1959. Saint Matthew Island reindeer-range study. U.S. Fish
Wildl. Serv., Spec. Sci. Rep.—Wildl. 43. 48 pp.
LeResche, R. E., and R. A. Hinman, eds. 1973. Alaska's wildlife and
habitat. Alaska Department of Fish Game, Juneau. 144 pp. + 564
maps.
Maher, W. J. 1974. Ecology of pomarine, parasitic, and long-tailed
jaegers in northern Alaska. Pac. Coast Avivauna 37. 148 pp.
McGregor, R. C. 1902. A list of birds collected in Norton Sound,
Alaska. Condor 4(6):135-144.
Mickelson, P. G. 1975. Breeding biology of cackling geese and
associated species on the Yukon-Kuskokwim delta, Alaska. Wildl.
Monogr. 45. 35 pp.
Murie, O. J. 1959. Fauna of the Aleutian Islands and Alaska Peninsula.
U.S. Fish Wildl. Serv., N. Am. Fauna 61:1-364.
Nelson, E. W. 1883. Birds of the Bering Sea and Arctic Ocean. Pages
44-120 in Cruise of the Revenue-steamer Corwin in Alaska and the
N. W. Arctic Ocean. U.S. Treas. Dep. Doc. 429.
Nelson, E. W. 1887. Report on natural history collections made in
Alaska between the years 1877 and 1881. U.S. Army, Signal Serv.
Arct. Ser. Publ. 3. 337 pp.
Orth, D. J. 1967. Dictionary of Alaska place names. U.S. Geol. Surv.
Prof. Pap. 567. 1084 pp.
Osgood, W. H. 1904. A biological reconnaissance of the base of the
Alaska Peninsula. U.S. Dep. Agric., Div. Biol. Surv., N. Am.
Fauna 24:9-86.
Palmer, R. S., ed. 1962. Handbook of North American birds. Vol. 1.
Loons through flamingos. Yale Univ. Press, New Haven, Conn.
567 pp.
Palmer, W. 1899. The avifauna of the Pribilof Islands. Pages 355-431 in
D. S. Jordan, ed. The fur seals and Fur Seal Islands of the North
Pacific, Part III. U.S. Treasury Department, Commercial Fur-seal
Investigations, Washington, D.C.

Petersen, M. R. 1976. Breeding biology of arctic and red-throated
loons. M. S. Thesis. Univ. of California, Davis. 55 pp.
Pitelka, F. A. 1959. Numbers, breeding schedules, and territoriality in
pectoral sandpipers of northern Alaska. Condor 61(4):233-264.
Pitelka, F. A. 1974. An avifaunal review for the Barrow region and
North Slope of Alaska. Arct. Alp. Res. 6(2):161-184.
Pitelka, F. A., R. T. Holmes, and S. F. MacLean, Jr. 1974. Ecology and
evolution of social organization in arctic sandpipers. Am. Zool.
14:185-204.
Pitelka, F. A., P. Q. Tomich, and G. W. Treichel. 1955. Ecological
relations of jaegers and owls near Barrow, Alaska. Condor 57(1):
3-18.
Portenko, L. A. 1973. The birds of the Chukotsk Peninsula and Wrangel
Island. Acad. Sci. S.S.S.R., Zool. Inst., Sci. Publishers, Leningrad.
2 vols. [In Russian.]
Preble, E. A., and W. L. McAtee. 1923. A biological survey of the
Pribilof Islands, Alaska. Part I. Birds and mammals. U.S. Bur.
Biol. Surv., N. Am. Fauna 46:1-128.
Sealy, S. G. 1973. Breeding biology of the horned puffin on St.
Lawrence Island, Bering Sea, with zoogeographical notes on the
North Pacific puffins. Pac. Sci. 27:99-119.
Sealy, S. G., F. H. Fay, J. Bédard, and M. D. F. Udvardy. 1971. New
records and zoogeographical notes on the birds of St. Lawrence
Island, Bering Sea. Condor 73(3):322-336.
Selkregg, L. L., ed. [1975]. Alaska regional profiles: Arctic region.
Univ. Alaska, Arct. Environ. Inf. Data Cent., Anchorage. 218 pp.
Shepherd, P. E. K. 1960. Production and abundance of the black brant
in Alaska. Alaska Dep. Fish Game, Game Div. Pittman-Robertson
Proj. Rep. 2(8):58-77.
Swarth, H. S. 1934. Birds on Nunivak Island, Alaska. Pac. Coast
Avifauna 22. 64 pp.
Swartz, L. G. 1966. Sea-cliff birds. Pages 611-678 in N. J. Wilimovsky
and J. N. Wolfe, eds. Environment of the Cape Thompson region,
Alaska. U.S. AEC, Div. Tech. Inf., Oak Ridge, Tennessee.

Thompson, C. F. 1967. Notes on the birds of the Northeast Cape of St.
Lawrence Island and of the Punuk Islands, Alaska. Condor
69(4):411-419.
Thompson, M. C., J. Q. Hines, and F. S. L. Williamson. 1966.
Discovery of the downy young of Kittlitz's murrelet. Auk
83(3):349-351.
Tuck, L. 1960. The murres. Can. Wildl. Serv. Ser. 1. 260 pp.
Turner, L. M. 1886. Contributions to the natural history of Alaska. U.S.
Army, Signal Serv. Arct. Ser. Publ. 2. 226 pp.
U.S. Fish and Wildlife Service. 1972. Nunivak National Wildlife
Refuge wilderness study report. Agency, Anchorage, Alaska. 200
pp.
U.S. Fish and Wildlife Service, Alaska Planning Group. 1973a.
Proposed Alaska Coastal Refuges, Alaska. Agency Draft Environ.
Statement 73-94. 247 pp. + appendixes.
U.S. Fish and Wildlife Service, Alaska Planning Group. 1973b.
Proposed Togiak National Wildlife Refuge. Agency Draft Environ.
Statement 73-100. 183 pp. + appendixes.
U.S. Fish and Wildlife Service, Alaska Planning Group. 1973c.
Proposed Yukon Delta National Wildlife Refuge, Alaska. Agency
Draft Environ. Statement 73-101. 205 pp. + appendixes.
U.S. National Park Service, Alaska Planning Group. 1973. Proposed
Chukchi-Imuruk National Wildlands, Alaska. Agency Draft
Environ. Statement 73-84. 306 pp. + appendixes.
Watson, G. E., and G. J. Divoky. 1975. Marine birds in the Beaufort
Sea. Pages 681-695 in J. C. Reed and J. E. Sater, eds. The coast
and shelf of the Beaufort Sea. Arctic Institute of North America,
Washington, D.C.
Williamson, F. S. L. 1957. Ecological distribution of birds in the
Napaskiak area of the Kuskokwim River delta, Alaska. Condor
59(5):317-338.
Williamson, F. S. L., M. C. Thompson, and J. Q. Hines. 1966. Avifaunal
investigations. Pages 437-480 in N. J. Wilimovsky and J. N.
Wolfe, eds. Environment of the Cape Thompson region, Alaska.
U.S. AEC, Div. Tech. Inf., Oak Ridge, Tennessee. 1250 pp.

FOOTNOTES:

[2] Present address: U.S. Fish and Wildlife Service, 500 NE Multnomah Street, Portland,
Oregon 97232.

Breeding Distribution and Status of Marine Birds in the Aleutian
Islands, Alaska

by
Palmer C. Sekora[3]
U.S. Fish and Wildlife Service
Kailua, Hawaii
G. Vernon Byrd[4]
U.S. Fish and Wildlife Service
Adak, Alaska
and
Daniel D. Gibson
University of Alaska
Fairbanks, Alaska

Abstract

Seabird population estimates are generally lacking for the 1,800-km-
long Aleutian Islands. Only the locations of the larger colonies are
known, and for these there are only imprecise estimates of colony
sizes and often even of species composition. Changes in the status of
several species and populations resulting from geologic and marine
actions and from human intrusions are evident. Accounts are given
for 25 species of marine birds breeding in these islands.
The 1,800-km-long chain of islands known as the Aleutians provides nesting habitat
for various species of marine birds, including three species of Procellariiformes and
three of cormorants (Phalacrocorax spp.), one species of gull (Larus glaucescens),
both kittiwake species (Rissa spp.), two species of terns (Sterna spp.), and at least 13
species of alcids.
Seabird population estimates of known accuracy are lacking for this isolated area.
Locations of larger colonies of breeding seabirds are known, however, and sufficient
data are available to place colonies in broad size ranges. Published information on the
breeding biology of marine birds is also lacking from the Aleutians, but some studies

are under way. The distribution of nesting marine birds away from the nesting cliffs is
totally unknown.
Introduced predators, primarily arctic foxes (Alopex lagopus), are now found on
nearly every island. Breeding marine bird populations have suffered drastic reductions
as a result. They have probably also changed because of natural habitat modifications
caused by earthquakes, volcanic eruptions, tidal waves, and marine erosion.
The purpose of this paper is to summarize the known present distribution and status of
breeding marine birds in the Aleutian Islands.
Description of the Aleutian Islands
The Aleutian Islands form an arc that separates the Bering Sea and the north Pacific
Ocean (Fig. 1). The island chain extends from the tip of the Alaska Peninsula to within
483 km of the Commander Islands of Siberia. The chain contains more than 200
islands—the peaks of a submarine volcanic mountain range. Volcanic activity and
earthquakes occur regularly.
Weather is characterized by perpetual overcast, dense summer fog, high-velocity
winds, and mild temperatures with low annual and diurnal variations. The sea is ice-
free year-round except in extremely cold winters, when the arctic ice pack may reach
the extreme northern islands.
The Aleutians are treeless except for a few introduced, stunted spruces. Woody shrubs
are restricted to the most northern islands on each end of the Chain. Mosses, lichens,
club mosses, and heaths are common ground-cover plants, and taller grasses, sedges,
and umbellifers constitute the overstory. Hulten (1960) provided a list of terrestrial
plants found in the Aleutians. Amundsen and Clebsch (1971) discussed terrestrial
plant ecology at Amchitka, central Aleutians. The marine plant communities around
the islands are fairly diverse. Lebednik et al. (1971) described marine algal
communities at Amchitka.
The easternmost Aleutian island, Unimak, has a mammalian fauna like that of the
Alaska Peninsula, including brown bear (Ursus arctos), caribou (Rangifer tarandus),
wolf (Canis lupus), and wolverine (Gulo gulo). West of Unimak, red foxes (Vulpes
fulva) occurred historically as far as Umnak, and arctic foxes were apparently on Attu
when the Russians came in 1741 (Murie 1959). Except for man and dog, no land
mammals occurred between Umnak and Aggatu islands. Arctic foxes, introduced
before 1930 for fur farming, still roam almost every island. Norway rats (Rattus
norvegicus) were introduced on many islands when ships were wrecked or as a result
of military activities during World War II.
Sea otters (Enhydra lutris) have repopulated most of the Aleutians after being nearly
extirpated by 1900. Rookeries of Steller's sea lion (Eumetopias jubata) are scattered
throughout the Aleutians during summer, and numerous harbor seals (Phoca vitulina)
haul out on beaches and offshore rocks.

All five species of Pacific salmon (Oncorhynchus spp.) occur near the islands, and at
least four of them (all but O. tshawytscha) spawn in Aleutian streams. Dolly Varden
(Salvelinus malma) and three-spine sticklebacks (Gasterosteus aculeatus) are found
nearly everywhere there is fresh water. The marine environment provides habitat used
by at least 77 species of fish (Isakson et al. 1971). O'Clair and Chew (1971) furnished
a recent reference to littoral macrofauna at Amchitka.
About 200 species of birds have been recorded in the Aleutians (Aleutian Islands
National Wildlife Refuge, unpublished data). Many of these are windblown stragglers
from both North America and Asia; only 59 species breed on the islands. Although
seabirds make up less than half (26 species or 44%) of the breeding birds, they may
compose more than 90% of the breeding avian biomass.

Ornithological Investigations in the Aleutians

Published ornithological information from the Aleutian Islands is relatively scarce. G.
W. Steller, naturalist on Vitus Bering's 1741 expedition to Alaska, was the first person
to record ornithological information in the islands (Stejneger 1936). More than a
century passed before W. H. Dall (1873, 1874) published the next papers dealing with
birds in the Aleutians. In 1878, the U.S. Army Signal Corps sent L. M. Turner to the
Aleutians to set up weather stations at several locations. Turner kept notes on birds at
various locations in the Aleutians and published two papers (1885, 1886) on his
observations. Turner's data (1886) provided the first report based on extended and
widespread observations in the area. E. W. Nelson, who replaced Turner, also
provided data on birds (Nelson 1887).
In 1906, A. C. Bent came to the Aleutians specifically to look for birds, and he and
Alexander Wetmore recorded birds throughout the island chain (Bent 1912). A. H.
Clark (1910) provided a valuable record of his observations in the Near Islands. All
these workers recorded birds in several locations, but none provided data on more
than a very few seabird colonies.

Fig. 1. The Aleutian Islands.

O. J. Murie, U.S. Biological Survey, made the most complete survey of the Aleutians
(Murie 1959). He specifically recorded seabird colonies, spending parts of four
summers in the area. Murie visited every large Aleutian island and most small ones.
He recorded nearly every major colony of cliff-nesting or talus-nesting seabirds
known in the Aleutians, but seldom gave sizes of colonies, and separate colonies on a
particular island were often not differentiated.
World War II brought several ornithologists to the Aleutians. Cahn (1947), Sutton and
Wilson (1946), Taber (1946), and Wilson (1948) provided accounts of birds observed
at specific locations. After the war, Fish and Wildlife Service personnel—including I.
N. Gabrielson (Gabrielson and Lincoln 1959), K. W. Kenyon (Kenyon 1961), and R.
D. Jones (Refuge Narrative Reports 1949-1970)—recorded observations of breeding
seabirds at several locations in the Aleutians. Investigations associated with Atomic
Energy Commission nuclear testing at Amchitka Island provided the first ecological
study of avifauna of an Aleutian island (White et al. 1977). Byrd et al. (1974)
provided a list of birds at Adak.
In 1971, the Near Islands were surveyed by U.S. Fish and Wildlife personnel in a
Cape Cod dory. In 1972, the Aleutian Islands National Wildlife Refuge obtained a
vessel, the Aleutian Tern, which allowed visits to all parts of the island chain. That
year, nearly every large island as far west as Buldir was visited, and seabird colonies
were mapped. Every island has been visited at least once since 1972.

Methods

In estimating the current status of seabirds in the Aleutians, all available data were
considered. Most of the information used, however, is from surveys conducted by the
U.S. Fish and Wildlife Service (1970-75, unpublished data). Because these surveys
only incidentally included Unimak, Akun, Akutan, Unalaska, and Umnak islands, data
for these areas are almost totally lacking. Data for Bogoslof, Adak, Amchitka, Buldir,
Agattu, Nizki, Alaid, and Attu are most accurate because fairly intensive
investigations have been conducted there since 1970.
The available data are of unknown accuracy. The method used by most investigators
who have surveyed areas in the Aleutians for seabird colonies has been to circle
islands in a ship or small boat; when a colony was encountered, they simply estimated
the number of birds they saw at the time. The accuracy of the estimates is affected by
weather, distance from the colony, density of birds, ability and experience of the
observer, and other variables. Estimates of kittiwakes and cormorants should be the
most accurate, since nests were actually counted. Murres (Uria spp.) are readily
visible on the cliffs, but the percentage of breeders on the cliffs at a particular time of
day during a particular part of the breeding season is not known. Auklet numbers are
perhaps hardest to estimate, since swirling "clouds" of birds are encountered.

Even when the estimates of birds seen are assumed to be accurate, data interpretation
is complex. Lack of information on diurnal rhythms adds difficulty to data
interpretation. Counts of burrow-nesting birds (e.g., puffins) have been inaccurately
interpreted because of the lack of understanding of their nesting ecology. Gulls (Larus
spp.), terns, and jaegers (Stercorarius spp.) are not well known since shore parties
have seldom investigated island interiors. Nocturnal species (e.g., ancient murrelet,
Synthliboramphus antiquus, and storm-petrels, Oceanodroma spp.) are perhaps the
least known. Since only crude estimates of colony sizes are available, broad limits are
used in this paper to describe known colonies.

Status and Distribution of Breeding Seabirds

Even from the sparse literature available, it is apparent that some seabird populations
are now drastically different from those in the Aleutians around 1900. Changes in
nesting habitat due to volcanic eruptions, tidal waves, marine erosion, and earthquakes
have occurred for centuries, and colonial nesting bird populations have fluctuated
accordingly. In addition, native Aleuts used marine birds and their eggs for food and
their skins for clothing, but the Aleuts were so diminished in numbers by 1900 that
they have had little recent effect on the bird populations.
From about 1900 to 1936, arctic foxes were introduced to most of the Aleutians for fur
farming. The foxes lived on birds in summer, and some species (e.g., Aleutian Canada
geese, Branta canadensis leucopareia) were wiped out wherever foxes were
introduced. Ground-nesting and some burrow-nesting seabirds were also drastically
reduced or extirpated on many islands.
During World War II the thousands of troops in the Aleutians brought dogs and cats to
some of the islands as pets, and many of the animals were set free when the men
departed. The military also accidentally introduced Norway rats to some of the
islands. Their role in seabird population reductions is unknown.
Figures 2-15 (pages 40-46) present data on the distribution of populations of birds that
have survived the foxes and other introduced predators. An annotated list of seabirds
breeding in the Aleutians follows.

Annotated List of Species

Northern fulmar (Fulmarus glacialis)

Northern fulmars breed on only three islands: Buldir (200 pairs), Gareloi (1,500
pairs), and Chagulak (more than 100,000 pairs). Fulmars were apparently much more
widespread formerly (Murie 1959; Turner 1886). Introduced foxes were probably
involved in the decline.

Fork-tailed Storm-petrel and Leach's Storm-petrel (Oceanodroma furcata and O. leucorhoa)

The distribution of storm-petrels is poorly known due to their nocturnal behavior near
the nesting colonies. The presence of birds has generally been noted by finding them
aboard ships anchored near islands after darkness. Population estimates are not
available for any colonies, so symbols used in Fig. 3 indicate probable numbers of
breeding birds. In few cases have active burrows or crevices been discovered. Storm-
petrels were formerly much more common. Murie (1959) and John L. Trapp (personal
communication) found large numbers of storm-petrel remains in fox dens. Most
present breeding colonies are probably confined to offshore islets and fox-free islands.

Double-crested Cormorant, Pelagic Cormorant, and Red-faced Cormorant (Phalacrocorax auritus, P. pelagicus, and P. urile)

Double-crested cormorants breed as far west as the Islands of Four Mountains. The
colonies vary in size from a few to 25 pairs. Pelagic and red-faced cormorants nest
from Amak to Attu on nearly every island. Relative abundance of the two in mixed
colonies varies between areas as well as from year to year. Red-faced cormorants tend
to nest in colonies mixed with kittiwakes and murres, but pure colonies also occur.
Pelagic cormorants occupy isolated, small colonies, but they also nest with kittiwakes
and murres and are often found with red-faced cormorants. By far the densest
concentration of cormorants occurs in the Near Islands, especially at Attu, where an
estimated 77,000 birds were seen in 1970. In the Aleutians as a whole, red-faced
cormorants outnumber pelagic cormorants, and double-crested cormorants make up
only a very small percentage of the breeding population.

Parasitic Jaeger (Stercorarius parasiticus)

The distribution of jaegers is poorly known because investigators have spent little
time ashore on most islands. Murie (1959) found jaegers on a number of islands, and
most of the data in Fig. 5 are his. Population estimates are available only for Amchitka
(25 pairs; White et al. 1977) and Buldir (30-40 pairs; G. V. Byrd, unpublished data).

Glaucous-winged Gull (Larus glaucescens)

Glaucous-winged gulls no longer nest on islands where foxes occur except where
islands in lakes are available. Most colonies are on offshore rocks or islets and range
in size from a few pairs to over 200 pairs, and occasionally more. They are found
throughout the Aleutians, but the largest known colonies are at Bogoslof (500 pairs)
and Buldir (250 pairs).

Black-legged Kittiwake and Red-legged Kittiwake (Rissa tridactyla and R. brevirostris)

Black-legged kittiwakes breed locally in every major island group, usually mixed with
murres and cormorants. The large colonies contain over 25,000 birds, but colonies of
less than 50 pairs also occur. Red-legged kittiwakes breed only on Buldir and
Bogoslof. They are remnants of a previously more widespread population.

Arctic Tern and Aleutian Tern (Sterna paradisaea and S. aleutica)

Terns breed locally in each island group. Both species occur at Attu, Amchitka, Adak,
and Umnak, but only arctic terns are found at Nizki. Factors limiting distribution are
unknown. Colonies vary in size from less than 10 pairs to 100 pairs.

Common Murre and Thick-billed Murre (Uria aalge and U. lomvia)

Like kittiwakes, murres are abundant locally. A pure colony of either species is almost
unknown, although one species often makes up more than 90% of a colony. Common
murres may have been reduced by foxes, since they tend to use sites with less slope
than those used by thick-billed murres. At Bogoslof and the Baby islands, the birds
use inland, gently sloping areas because there are no foxes. The presence of the lichen
(Caloplaca spp.), which according to Tuck (1960) is indicative of bird roosts, on
several extensive cliff areas suggests that either murres or kittiwakes, or both,
formerly used areas they do not use now.

Pigeon Guillemot (Cepphus columba)

This species has been noted near almost every island that has been visited. Nesting
under beach boulders and driftwood, the birds only occasionally are found in large
concentrations (near Great Sitkin more than 4,000 birds were seen in 1971). Murie et
al. (1937) summed up the distribution of pigeon guillemot accurately: "Each island
has its meager quota of these birds, nesting unobtrusively among the rocks but never
assembled in any really large groups." Estimates of populations may be extremely
inaccurate because the diurnal rhythm of the pigeon guillemot is unknown.

Marbled Murrelet and Kittlitz's Murrelet (Brachyramphus marmoratus and B. brevirostris)

Nests of neither species have been located in the Aleutians, but nesting of both is
suspected at Adak, Unalaska, and Unimak, where specimens of Kittlitz's with brood
patches or eggs in the oviduct have been collected in nearshore waters. Courtship has
been recorded in marbled murrelets (Byrd et al. 1974).

Ancient Murrelet (Synthliboramphus antiquus)

The distribution of this species is very poorly known, since it is nocturnal near nesting
colonies. Murie (1959) wrote, "This is one of the species that undoubtedly has greatly
declined in recent years, as a result of increase of the blue-fox industry." The leading
of downy young to sea by the adults is a very noisy process and foxes could easily
take large numbers. Also, these murrelets nest in fairly shallow burrows which foxes
could dig out easily. Birds were recorded near islands in every group during surveys
from 1972 to 1975, but workers seldom went ashore to determine if they were nesting.
In Fig. 12, the only basis for designating most of the areas marked as colonies is the
presence of birds during breeding season (15 May-1 July).

Cassin's Auklet (Ptychoramphus aleuticus)

This is another species that was more common before the fox was introduced. Cassin's
auklet now seems to occur only locally, but these nocturnal birds are probably often
overlooked. They are known only from Buldir, Umnak, and the vicinity of Oglodak.

Parakeet Auklet (Cyclorrhynchus psittacula)

This auklet, which nests under beach boulders, in burrows, and in rock crevices,
seems to use a greater variety of breeding sites than do the other auklets. The largest
known colony is at Chagulak, where an estimated 10,000 were seen in 1972. Smaller
colonies are found as far west as Buldir.

Crested Auklet, Least Auklet, and Whiskered Auklet (Aethia cristatella, A. pusilla, and A. pygmaea)

Aethia nest primarily in rock crevices of talus slides. Such habitat occurs locally in
each major island group except the Near Islands. Least auklets outnumber crested
auklets in the Aleutians, and whiskered auklets are far less common than either.
Estimates of populations are probably grossly inaccurate because of the difficulty both
in estimating the number of birds in the milling flocks observed and in interpreting the
estimates after they are obtained.

Horned Puffin and Tufted Puffin (Fratercula corniculata and Lunda cirrhata)

Horned puffins favor rock crevices in talus slides and cliff faces for nesting, whereas
tufted puffins are primarily burrow nesters. The historical distribution of the two
species was probably based on availability of nesting sites, so tufted puffins were
more widespread and numerous. However, in areas where extensive talus slopes are
available, horned puffins reached high densities. Predation by introduced foxes may
have altered the distribution of tufted puffins, which now nest primarily on fox-free
islets just offshore from the larger islands where foxes occur. The distribution of

horned puffins may not have been altered significantly, since they are relatively free
from fox predation in their rock crevices.

Recommendations

A complete survey of the Aleutian Islands has not been done. This should be done, by
methods that will provide accurate population estimates. Life history information is
needed on almost all species, and data should be gathered on selected populations to
determine trends. Information on winter distribution should also be compiled. The
effects of introduced predators should be evaluated quantitatively, and if control
measures are needed, effective, humane methods should be devised and implemented.

Acknowledgments

The authors are grateful to the following Fish and Wildlife Service personnel who
helped collect previously unpublished data used in this paper: E. P. Bailey, C. S.
Craighead, C. P. Dau, M. H. Dick, G. J. Divoky, R. Martin, J. L. Trapp, G. W. Watson,
and C. M. White. Most of the data were collected from the deck of the Aleutian
Islands National Wildlife Refuge research vessel Aleutian Tern. Captain George
Putney is acknowledged for his peerless seamanship and constant encouragement; he
also contributed observations of birds.
The maps were adapted from a master supplied by Elaine Rhode, Public Affairs
Office, U.S. Fish and Wildlife Service, Anchorage; she also suggested the use of
squares to display data. C. M. White graciously made his in-press manuscript
available. W. B. Emison, R. J. Gordon, and J. L. Trapp kindly made their field notes
available, and Trapp helped compile data. Most of the funds for the surveys in 1971-
75 were provided by the U.S. Fish and Wildlife Service.

References

Amundsen, C. C., and E. E. C. Clebsch. 1971. Dynamics of the terrestrial
ecosystem vegetation of Amchitka Island, Alaska. Bioscience
21:619-623.
Bent, A. C. 1912. Notes on birds observed during a brief visit to the
Aleutian Islands and Bering Sea in 1911. Smithsonian Misc. Coll.
56(2):1-29.
Byrd, G. V., D. D. Gibson, and D. L. Johnson. 1974. The birds of Adak
Island, Alaska. Condor 76:288-300.

Cahn, A. R. 1947. Notes on the birds of the Dutch Harbor area of the
Aleutian Islands. Condor 49:78-82.
Clark, A. H. 1910. The birds collected and observed during the cruise of
the United States Fisheries steamer "Albatross" in the north Pacific
Ocean and in the Bering, Okhotsk, Japan, and Eastern seas from
April to December 1906. Proc. U.S. Natl. Mus. 38:25-74.
Dall, W. H. 1873. Notes on the avifauna of the Aleutian Islands, from
Unalaska eastward. Proc. Calif. Acad. Sci. 5:25-35.
Dall, W. H. 1874. Notes on the avifauna of the Aleutian Islands,
especially those west of Unalaska. Proc. Calif. Acad. Sci. 5:270-281.
Gabrielson, I. N., and F. C. Lincoln. 1959. The birds of Alaska. The
Stackpole Co., Harrisburg, Penn., and Wildlife Management
Institute, Washington, D.C. 922 pp.
Hulten, E. 1960. Flora of the Aleutian Islands. J. Kramer,
Weinham/Bergstr., Sweden. 376 pp.
Isakson, J. S., C. A. Sinensted, and R. L. Burgner. 1971. Fish
communities and food chains in the Amchitka area. Bioscience
21:666-670.
Jones, R. D. 1949-1970. Annual refuge narrative reports, Aleutian Islands
N.W.R. Cold Bay, Alaska. (Unpublished administrative report.)
Kenyon, K. W. 1961. Birds of Amchitka Island, Alaska. Auk 78:305-326.
Lebednik, P. A., F. C. Weinmann, and R. E. Norris. 1971. Spatial and
seasonal distributions of marine algal communities at Amchitka
Island, Alaska. Bioscience 21:656-660.
Murie, O. J. 1959. Fauna of the Aleutian Islands and Alaska Peninsula.
U.S. Fish Wildl. Serv., N. Am. Fauna 61. 364 pp.
Nelson, E. W. 1887. Report upon natural history collections made in
Alaska between the years 1877 and 1881. U.S. Army, Signal Serv.
Arct. Ser. Publ. 3. 337 pp.
O'Clair, C. E., and K. K. Chew. 1971. Transect studies of littoral
macrofauna, Amchitka Island, Alaska. Bioscience 21:661-664.
Stejneger, L. 1936. George Wilhelm Steller—the pioneer of Alaska
natural history. Harvard University Press, Cambridge, Mass. 623 pp.
Sutton, G. M., and R. S. Wilson. 1946. Notes on the winter birds of Attu.
Condor 48:83-91.

Taber, R. D. 1946. The winter birds of Adak, Alaska. Condor 48:272-277.
Tuck, L. M. 1960. The murres. Ottawa. Canadian Wildlife Series 1. 260
pp.
Turner, L. M. 1885. Notes on the birds of the Near Islands, Alaska. Auk
2:154-159.
Turner, L. M. 1886. Contributions to the natural history of Alaska. U.S.
Army, Signal Serv. Arct. Ser. Publ. 2. 226 pp.
White, C. M., F. S. L. Williamson, and W. B. Emison. 1977. Avifaunal
investigations. Pages 227-260 in M. L. Merritt and R. G. Fuller, eds.
Environments of Amchitka Island, Alaska. U.S. Energy Research
and Development Association, Oak Ridge, Tenn. 682 pp.
Wilson, R. S. 1948. The summer bird life of Attu. Condor 50:124-129.

Fig. 2. Breeding distribution of northern fulmar.

Fig. 3. Breeding distribution of storm-petrels.

Fig. 4. Breeding distribution of cormorants.

Fig. 5. Breeding distribution of parasitic jaeger.

Fig. 6. Breeding distribution of glaucous-winged gull.

Fig. 7. Breeding distribution of kittiwakes.

Fig. 8. Breeding distribution of terns.

Fig. 9. Breeding distribution of murres.

Fig. 10. Breeding distribution of pigeon guillemot.

Fig. 11. Breeding distribution of marbled and Kittlitz's murrelet.

Fig. 12. Breeding distribution of ancient murrelet.

Fig. 13. Breeding distribution of auklets.

Fig. 14. Breeding distribution of horned puffin.

Fig. 15. Breeding distribution of tufted puffin.

FOOTNOTES:

[3] Present address: U.S. Fish and Wildlife Service, William L. Finley National Wildlife
Refuge, Route 2, Box 208, Corvallis, Oregon 97330.
[4] Present address: U.S. Fish and Wildlife Service, Kilauea, Hawaii.

The Historical Status of Nesting Seabirds of the Northern and
Western Gulf of Alaska

by
LeRoy W. Sowl
U.S. Fish and Wildlife Service
1011 East Tudor Road
Anchorage, Alaska 99507

Abstract

The history of ornithological field work in the Gulf of
Alaska dates back to 20 July 1741 and Bering's discovery of
Alaska. In spite of this long history, the record is
fragmentary and often seemingly contradictory. The coming
of the tanker terminal at Valdez and the pending
development of oil and gas resources on the outer
continental shelf threaten massive change for seabirds in the
Gulf of Alaska. Often overlooked, however, is the fact that
man has already effected a change in status for many of
these birds. In this paper I examine the scanty, general
record from the exploratory period, roughly 1741 to 1935,
and the somewhat more comprehensive record of the
reconnaissance period, 1936-74, and attempt to develop a
basis for better understanding of the change in seabird status
that has already taken place. This paper should be treated as
a verbal model which can be improved as our knowledge of
seabirds in the Gulf of Alaska is expanded.
From the perspective of history, 1970 should prove to have been a
momentous year for Alaska and its seabirds. Two events, the construction of
the Trans-Alaska Pipeline and the passage of the National Environmental

Policy Act (NEPA) merged head on in 1970 with the decision that Section
2c of NEPA applied to the proposed pipeline. The systematic appraisal of
potential environmental impacts required by Section 2c quickly exposed the
inadequacy of the existing data base in many areas. With respect to seabirds
in the Gulf of Alaska, it was apparent that there had never been any effort to
develop a synthesis of the information accumulated over 230 years. The
data gaps which were uncovered were appalling.
While the Trans-Alaska Pipeline impact statement had provided shock
therapy, it was not the only influential event on the horizon. Two local
disturbances had already preceded the pipeline. These were Project Chariot
at Cape Thompson and the Amchitka Island test program. Now in quick
succession the Wilderness Act and native land claims added new urgency to
the need for solid resource information. More recently, the outer continental
shelf minerals leasing program has made the quick development of base-
line information even more essential.
All of the new activity in Alaska's coastal waters has the potential to affect
seabirds in one way or another. We must remember, however, that man's
activities have been affecting seabirds for a long time. We cannot accurately
assess the effect of a tanker terminal at Valdez or offshore oil activity
without first developing some understanding of the current status of
seabirds in the context of the historical record.
Seabird work in Alaska can be divided roughly into three periods. The first
is the early historical or exploratory period; it extended from Georg Steller's
1741 visit to Kayak Island to 1935. This was literally a period of
exploration and the collection of information was dependent upon interest
and opportunity. The second is the reconnaissance period; during this period
investigators were dispatched to a particular area to gather general
information for management application. This period begins with Murie's
extensive investigations of the Alaska Peninsula and the Aleutian Islands; I
see it extending from 1936 to 1975. In 1975 the need for data became so
acute that it was necessary to enter the third period, one of intensive data
gathering. Knowing where the big seabird colonies were located and
knowing their general species composition was no longer adequate. The
current intensive data-gathering effort in the waters over oil and gas leasing
areas is a partial response to the recognition of this inadequacy.

In this paper I draw some tentative conclusions relative to the status of the
26 species of primary seabirds (Fisher and Lockley 1954) breeding in, or
which may have bred in, the northern and western Gulf of Alaska area. This
area extends from Cape Fairweather, 59°N 138°W, westerly along the coast
to Ikatan Bay, 55°N 163°W, at the end of the Alaska Peninsula. These bird
species tend to be colonial, but not exclusively so. Two birds which are
primary seabirds, the mew gull (Larus canus) and Bonaparte's gull (L.
philadelphia), have not been included because they tend to be more riverine
than marine in habit. Several marine ducks have been excluded because
they are secondary seabirds.
Information from the early exploratory period is summarized under the next
section. The more detailed information from the reconnaissance period is
discussed in the species accounts.

Summary of the Historical Record

The history of ornithological field work in the Gulf of Alaska goes back 235
years to 20 July 1741. On that day Bering's surgeon/naturalist, Georg W.
Steller, spent a scant 10 h ashore on Kayak Island. He collected a single
bird. This bird, later named for Steller, reminded him of a plate of the blue
jay by Make Catesby, the colonial-era predecessor of Audubon, in Volume 1
of the Natural History of Carolina, Florida, and the Bahama Islands
(Stejneger's annotated translation of Steller's journal in Golder 1925).
Collection of the bird confirmed for Steller that the first Russian Expedition
had reached America.
Steller was an accomplished naturalist, but his overbearing and superior
manner had apparently sorely irritated Bering and his officers long before
the expedition reached Kayak Island. The seamen made little effort to go
ashore anywhere in Alaska and Steller was blocked from doing so as well.
In addition to Kayak Island, he was able to go ashore only on Nagai Island,
first with a water party on 30 August and again the next day. He noted that
"all sorts of waterbirds in abundance were seen." These included two kinds
of cormorants, auks, ducks, gulls, divers, pigeon guillemots (Cepphus
columba), tufted puffins (Lunda cirrhata), and horned puffins (Fratercula
corniculata).

Stejneger's comment on the identity of the cormorants is interesting
because, based on his experience, he assumed them to be pelagic and
double-crested cormorants (Phalacrocorax pelagicus and P. auritus). He
gave no thought to red-faced cormorants (P. urile) which are now common
there.
Steller noted on 6 September off Bird Island in the Shumagin Islands, that
"when we were out to sea about half a mile we were especially astonished
at the untold numbers of seabirds which we saw on the northern side of the
island." These birds were listed as cormorants, auks, horned puffins,
fulmars (Fulmarus glacialis), pigeon guillemots, black oystercatchers
(Haematopus backmani), and a pied diver which Stejneger assumed was an
ancient murrelet (Synthliboramphus antiquus).
On 15 September when Bering's vessel, the St. Peter, was south of Amukta
Pass, Steller recorded observing "river gulls." The observation is not as
interesting as Stejneger's comment (Golder 1925) concerning it. Stejneger
stated that no true river gulls lived in the Aleutians and these must,
therefore, have been another small gull with red feet. He thought they must
have been the red-legged kittiwake (Rissa brevirostris), which "inhabits the
Aleutian Islands from Bering Island to Sannak."
Thirty-seven years after Bering's voyage, Captain James Cook sailed into
the Gulf of Alaska, arriving off Kayak Island on 11 May 1778. Cook was
not accompanied by an able naturalist. His surgeon, William Anderson, did
have some experience gained on earlier voyages in preparing skins and
taking notes, but he had contracted tuberculosis and became so ill that even
his notes ceased after 8 June, while the expedition was in Cook Inlet.
Cook was under orders to keep a careful record of everything he saw. One
of the results was that he had birds collected even though he had no
naturalist to do the work. Several birds were collected in Prince William
Sound while Cook's vessels were at anchor in Port Etches. These included
two marbled murrelets (Brachyramphus marmoratus—type specimens), a
black oystercatcher, a surfbird (Aphriza virgata), a surf scoter (Melanitta
perspicillata), and a red-breasted merganser (Mergus serrator—type
specimen), along with several forest birds (Stresemann 1949).
The watch journals of Cook and his officers provide some additional
information. Captain Charles Clerke (Beaglehole 1974) remarked in his log

on the passage out of Prince William Sound through Montague Strait on 20
May that "it had almost become tautology to mention whales and seals and
innumerable sea fowl that so confoundingly kept their distance."
Between the Trinity Islands and Chirikof Island on 18 June, Cook's men
collected a single tufted puffin. Later Cook passed close to the Semidi
Islands and the Shumagin Islands and directly through the Sandman Reefs.
Beaglehole's version of this part of the voyage makes no mention of
seabirds.
There is a gap of 87 years during which there is almost no hint of published
material bearing on the status of seabirds in the Gulf of Alaska. In 1865 the
Russo-American Telegraph Expedition touched this area. Dall and
Bannister (1869) provide us with a few scraps garnered during that
expedition, primarily by Bischoff. The glaucous-winged gull (Larus
glaucescens) was described as the most common species from California
northward. Bischoff's collections at Kodiak indicate that the horned and
tufted puffins were collected with ease. He was able also to collect an
Aleutian tern (Sterna aleutica—type specimen) along with an egg.
Dall (1873) noted in 1872 that the black-legged kittiwake (Rissa tridactyla)
was common at Round Island and Delarof Harbor, Unga Island, in the
Shumagins. The inference is that it was more common at these two places
than elsewhere. The Arctic tern (Sterna paradisaea) was abundant in the
Shumagin Islands and particularly at Range Island in Popoff Strait. Dall
expressed the opinion that the horned puffin was very abundant in the
Shumagins and appeared to fill the niche of the tufted puffin, which he did
not see there. The only other bird which he thought to be very common was
the pigeon guillemot. He did not note the common murre (Uria aalge) at
all.
In 1908 the second of three Alexander Expeditions conducted field work in
the Prince William Sound area. From Dixon (1908) and Grinnell (1910) we
can derive some basis for assessing status in a very general way. The most
common seabird noted was the marbled murrelet. Glaucous-winged gulls
and black-legged kittiwakes were common; the glaucous-winged gull was
the more common. Horned puffins were judged to be slightly more common
than tufted puffins by both authors. The northern end of Montague Strait
appears to have been the center of abundance for puffins. Dixon noted that

on 16 July 1908 there were swarms of puffins in the channel along Green
Island. Pigeon guillemots were common along the rocky coasts. Parakeet
auklets (Cyclorrhyncus psittacula), common murres, and ancient murrelets
were noted only in very small numbers.
After the Alexander Expeditions there was another doldrum in which little
was done. During this lull in activity, a note by Townsend (1913) appeared
which compared the numbers of crested auklets (Aethia cristatella) at
Yukon Harbor, Big Koniuji Island, to the least auklets (A. pusilla) of St.
George Island, stating that the crested auklets were more numerous. He
sailed into the Yukon Harbor anchorage on the evening of 1 August and
observed that crested auklets "were present in myriads. The surface of the
water was covered with them, and the air was filled with them."
The formal record available to researchers is very shallow for this
exploratory period. With a few exceptions it was compiled by non-
scientists, primarily explorers and egg and skin collectors.

Current Status

Setting the Stage

This paper should be viewed as a conceptual model. While I attempted to be
as objective as possible, subjectivity was unavoidable. Many of the
tentative conclusions are based on very little data. Each improvement will
make it a better management tool. Because of the space limitations, it is not
possible to go into a detailed tracking of my reasoning for each species. In
an attempt to overcome this handicap, I am including some examples of the
sorts of reasoning that went into the process.
In 1973 I led a Fish and Wildlife Service (FWS) reconnaissance survey
team that was delineating seabird colonies along the Alaska Peninsula. In
the Shumagin Islands we entered or crossed Koniuji Strait twice (on 11 and
12 June) without even suspecting the presence of a horned puffin colony. A
third passage through the strait (13 June) was not so uneventful. The water
and the air were filled with horned puffins. This led to the discovery that the
430-m mountain on the southeastern corner of Big Koniuji was also
covered with horned puffins, clear to its top. The minimum estimate of the
birds that were visible was 140,000. Even this number of birds would make

this the largest horned puffin colony ever discovered. David Spencer
(personal communication) had noted similar swarms of horned puffins in
this strait in 1956 while flying sea otter surveys in the area. In 1975 a field
camp was established at Yukon Harbor, with study of this colony as one of
the prime objectives of the investigators. As far as these investigators could
tell no such large colony existed there, even though the nesting habitat was
still there, unaltered. This sort of event, one of the banes and vagaries of
estimating seabird numbers, is not rare.
In 1973, when FWS personnel delineated the colony on the southwestern
end of Bird Island in the Shumagins, there were estimated to be 43,000
kittiwakes, 24,000 murres, and 6,000 cormorants present; no tufted puffins
were seen about the colony. The last time (in 1970) one of the observers,
Edgar Bailey, had visited the colony with Robert Jones, there was an
extremely large colony of tufted puffins which Jones (E. Bailey, personal
communication) estimated at more than 1 million birds. We made a
particular effort to visit Jude Island, between the Shumagin Islands and the
Pavlof Islands, because David Spencer (personal communication) had
reported once having seen the air over the island filled with an extremely
large number of tufted puffins. However, there were no puffins at this
colony either.
Let us examine the facts in context. On 8 June we had visited High Island
where we had attempted to collect puffin eggs for pesticide analysis, but
had been able to find only one egg. Also, there were only 6,000 tufted
puffins where George Putney, master/engineer of the Aleutian Tern, had
seen much larger numbers in 1972. These two facts could easily be related
to explain the current situation because it was still early in the breeding
season. The horned puffin observations in Koniuji Strait (11-13 June) were
in keeping with this conclusion also—an indication that these birds had not
yet settled down to a full breeding effort. The erratic comings and goings of
common puffins (Fratercula arctica) early in the season have been well
documented (Lockley 1962). It is an easy step to extend this reasoning to
the absence of birds at Bird Island on 11 June, even though fresh signs of
the characteristic evidence of tufted puffin occupancy were missing. Jude
Island provides a different clue, however. There were 3,000 pigeon
guillemots, an unheard-of concentration, apparently occupying abandoned
tufted puffin burrows on 15 June. Also, on 7 June we had made a very

interesting observation that had no special significance at the time: murres
on Spitz Island were occupying little parapets created by mashing down the
mouths of puffin burrows which filled the slope above the cliff portion of
their colony.
After looking at all of the observations cited above, I conclude that tufted
puffins were greatly reduced in numbers on these sites in 1973 and that they
had been absent from the burrows used by the murres and pigeon
guillemots for more than the current breeding season. What causes these
sorts of changes? I do not know.
One reason for year-to-year change may be local movements of colonies.
Black-legged kittiwakes nest at several places in lower Orca Inlet, Prince
William Sound. Counts made at these sites in 1972 and 1974 yielded almost
identical totals but the numbers of birds varied between individual sites.
This may be an indication that all of these sites are part of one large
composite colony and that, at least in this colony and for this species, the
birds shift at will.
The best record of population flux involving two species has been
summarized by Peterson and Fisher (1955). In 1872 and 1873 the murres
observed on Walrus Island in the Pribilofs were almost entirely common
murres. In 1890 common and thick-billed murres (Uria lomvia) were
evenly matched in number. By 1901 the colony was almost exclusively
dominated by thick-billed murres. In 1911 and 1914 the few thick-billed
murres present were almost lost among the then dominant common murres.
In 1940 thick-billed murres dominated again. When Peterson and Fisher
visited the island in 1953, the situation was again reversed and common
murres had almost completely replaced the thick-billed murres. These
changes are even more impressive because of the number of birds involved,
between 1 and 2 million in 1953. There are more tenuous indications that
somewhat the same thing may occur between two other congener pairs, the
pelagic and red-faced cormorants and the black-legged and red-legged
kittiwakes. The causative factor, or factors, is not readily apparent. One
possibility is long-term climatic fluctuation.
Dement'ev and Gladkov (1966) provide an example of abrupt and massive
change. Before 1876, the pelagic cormorant abounded on the Commander
Islands. During the winter of 1876-77, the birds were decimated by an

unknown epizootic disease. By spring only a few individuals remained
alive. The record shows that by 1882 they were already becoming common
again. Red-faced cormorants were apparently not reduced in number
because Dement'ev and Gladkov (1966) state that they were common in
"the second half of the last century and the beginning of this." Did they
flourish only while the pelagic cormorants were reduced in number?
Bowles (1908) gives another indication of naturally induced population
impact. He noted large numbers of dead seabirds on Washington beaches
and the ocean "rather plentifully dotted with sick birds ..." He examined
some birds and found "many hundreds" of tapeworms in every bird. His
conclusion was that their intestines were so solidly packed with tapeworms
that starvation was "an absolute certainty."
Some apparent disruptions are long term. In the Gulf of Alaska there is a
hiatus in the distributions of a number of small seabirds that are active
around their colonies only at night. Repeatedly, the northern Gulf of Alaska
shows up as an area of reduced population, as a boundary between
subspecies, or as a limit to a range. This same area has a noticeable lack of
total darkness during a substantial portion of the breeding season.
The nocturnal habit no doubt evolved because it was advantageous to
concentrate on the breeding grounds only under the cover of darkness,
when diurnal predators were at a great disadvantage. Cody (1973) states
that Cassin's auklet (Ptychoramphus aleuticus), which is strictly nocturnal
around its colonies, avoids these colonies on brightly moonlit nights. He
sees this as an apparent response to gull predation. At higher latitudes the
small alcids have overcome this disadvantage by swamping predators
through their sheer numbers. In the Gulf of Alaska I suspect that few of the
small seabirds, except possibly the fork-tailed storm-petrel (Oceanodroma
furcata), have ever achieved great enough numbers to offset the impact of
extended daylight.
Past disruptions of seabird populations are both natural and man-induced;
however, the documentary record is much too fragmentary to allow us to
fully appreciate what has occurred or what the long-term effect has been. To
give some perspective to the problems associated with assessing change and
attempting to understand it, some of the indicators of natural and unnatural
change and flux in seabird populations are reviewed here.

The flux in bird numbers can be related to the time of day, season of the
year, and atmospheric conditions on a short-term basis. This sort of flux or
apparent flux can easily be explained. The underlying cause of some of the
longer term flux is not so easily arrived at. Murie (1959), Gabrielson and
Lincoln (1959), and Sowl and Bartonek (1974) have noted some of the
man-induced changes. These are also explored to some extent in the species
accounts as they are found to apply.
I sometimes refer to a colony size class when discussing the existing data
rather than to an actual population estimate. The size classes used are
defined as follows:

Class I—less than 100 birds
Class II—100-1,000
Class III—1,000-10,000
Class IV—10,000-100,000
Class V—100,000-1,000,000
Class VI—more than 1,000,000

The Dictionary of Alaska Place Names (Orth 1967) is the reference for
those who wish to locate some of the less obvious sites. The Coast Pilot,
No. 9 (U.S. Department of Commerce 1964) is another useful reference.

Species Accounts

Northern Fulmar (Fulmarus glacialis)

Petrels of a number of species can be found in the Gulf of Alaska, some of
them in great numbers. Only the northern fulmar breeds there.
The fulmar is common in the offshore waters of the northern Gulf of Alaska
throughout most of the year (Isleib and Kessel 1973). Most authors,
including Clark (1911), one of the earlier ones, who commented on the
distribution of fulmars farther out in the Gulf, have considered them to be
abundant. Nichols (1927) raised one of the few voices of apparent dissent;
he noted that in 1926 he encountered the largest number of fulmars (about
800) on 11 July in Shelikof Strait after he had left the Gulf. During the
summer, fulmars are very common seaward of Montague Island,

particularly to the northeast of Patton Bay and in the approaches to
Montague Strait. Data derived from FWS surveys in July and August 1972
showed an estimated 10,000 fulmars in a stretch of waters 19 km wide
along the east side of Montague Island (Isleib and Kessel 1973).
Over the Portlock Banks and in Stevenson Entrance, fulmars sometimes
concentrate in very large numbers, either by themselves or in company with
sooty shearwaters (Puffinus griseus). In August 1973, FWS observers
crossing Perenosa Bay saw large numbers of tube-nosed birds moving
northeastward across the Bay. Although these appeared to be predominantly
shearwaters, there were also many fulmars. There was a general movement
of birds through Shuyak Strait from Shelikof Strait into the Gulf of Alaska.
It was not determined whether the fulmars were moving with the
shearwaters or on a regular feeding flight. Fulmars are often found close to
Afognak Island in the area between Sea Lion Rocks and Sea Otter Island.
Gabrielson and Lincoln (1959) reported seeing swarms of fulmars in
Marmot Strait and around the small islands on the north side of Afognak in
early August. Murie (1959) noted fulmars in Shelikof Strait and again
around the Shumagin Islands. There is nothing in this record to indicate any
change in their distribution at sea recently.
The Semidi Islands support the Gulf of Alaska's largest fulmar breeding
population, a Class V colony (U.S. Bureau of Sport Fisheries and Wildlife
1973). Gabrielson and Lincoln (1959) considered it to be one of the four
largest colonies in Alaska.
Gabrielson (1940) was told by Captain Sellevold of the marine vessel
Brown Bear that he thought the birds nested on Sea Otter Island in Perenosa
Bay. Gabrielson also learned that they probably nested on Sea Lion Rock at
the head of Marmot Strait. In August 1973 I observed fulmars in close
proximity to Sea Lion Rock. More recently, small numbers of apparently
breeding fulmars have been found in the Barren Islands (L. W. Sowl,
personal observation and Edgar Bailey, unpublished FWS report,
Anchorage, Alaska). Although no other colonies are known or suspected,
the evidence suggests the possible existence of some.
Peterson and Fisher (1955), on noting dark fulmars between St. Paul and St.
George when only the light morph was present on any of the colonies in the
Pribilofs, expressed no surprise. They offered the opinion that a round trip

of 960 km to one of the dark morph colonies in the Aleutians just might be
within the operating range of a fulmar on a 4-day vacation from nest-
tending duties. Using this as a general yardstick, it appears that the rich
foraging grounds over the Portlock Banks might also be within the range of
breeding fulmars from the Semidis. The trip up Shelikof Strait and on to
Portlock Bank by way of Shuyak Strait is only slightly longer than the one
from Chagulak to St. Paul. The feeding grounds off Montague Island would
require a 1,600-km round trip from the colonies in the Semidi Islands. Birds
from the Barren Islands and any colonies around Shuyak Island could easily
reach the Montague Island grounds, but why would they cross the Portlock
Banks to do so?
Fulmar colonies may be found in the Chiswell Islands. It is also a
possibility that the existence of colonies on islands along the north coast of
Afognak Island will be verified and that others will be found in the vicinity
of Shuyak Island. Gabrielson and Lincoln (1959) expressed the opinion that
there is almost certainly a colony on Sutwik Island. If there is one, however,
I did not see it on one quick trip around the island in 1973.
Gabrielson (1940) expressed surprise at the size of the Semidi Island
breeding colony. Gabrielson and Lincoln (1959) considered 1911 to be the
first time breeding fulmars were found in the Shumagins. They apparently
based this on two eggs collected there that year and documented in a plate
in Bent (1964). Other than Gabrielson's opinion, there is nothing to indicate
a major change in fulmar status during this century. If there has been a
change in status, it has probably been in the direction of increasing
populations.

Fork-tailed Storm-petrel (Oceanodroma furcata)

The fork-tailed storm-petrel probably breeds throughout the Gulf of Alaska.
It is abundant at sea during the summer in most offshore waters. Murie
(1959) described it as the dominant petrel in the Bering Sea and the North
Pacific.
In view of its wide distribution and apparent abundance very little is known
about the fork-tailed storm-petrel's breeding colonies. Friedmann (1935)
recorded specimens and eggs from Kodiak dating back to 1843. Murie
(1959) noted them as nesting on Sanak Island and stated that they almost

certainly nested in the Shumagins and on other islands along the Alaska
Peninsula. David Roseneau (Isleib and Kessel 1973) found this storm-petrel
"breeding by the 10,000's" on East Amatuli Island in the Barren Islands in
June 1965. This was subsequently verified in 1974 by Edgar P. Bailey
(unpublished report, FWS, Anchorage, Alaska).
On 2 July 1972, responding to a tip by James W. Brooks (personal
communication), M. E. Isleib and I anchored at Fish Island in the Wooded
Islands. We did not locate any storm-petrel burrows, but a steady flow of
storm-petrels passed over the boat throughout the darkest part of the night.
Surveys conducted at about that time provided an estimate of 19,000 fork-
tailed storm-petrels in Prince William Sound, primarily in or close to
Montague Strait, and in coastal waters on the east side of the Sound's outer
islands. In this area Isleib (personal communication) has noted a general
movement of fork-tailed storm-petrels westward around Montague Island
and into Prince William Sound through Montague Strait each morning and a
corresponding countermovement each evening. I conclude that in 1972
there was a Class IV colony in the Wooded Islands, numbering between
19,000 and 38,000 birds. Additional colonies will be discovered in a similar
manner as more systematic searches are made.
No colonies were discovered during the 1973 reconnaissance survey of the
islands south of Alaska Peninsula. Working primarily inshore, FWS
investigators encountered very few storm-petrels during the day. On the
night of 14 June, the FWS vessel, Aleutian Tern, responded to a Mayday
call and was either in transit or participating in rescue operations from 2245
to 0420 h on the morning of 15 June. During this period numerous fork-
tailed storm-petrels were encountered, particularly off Cape Wedge on
Nagai Island. After we anchored in Eagle Harbor on Nagai, more storm-
petrels were heard about the vessel.
At about this same date, National Marine Fisheries Service enforcement
officers flying fisheries patrols observed storm-petrels in abundance south
of the Shumagin Islands (James Branson, personal communication). These
observations support the belief that there are probably substantial
undiscovered colonies in the Shumagin Islands.
Fork-tailed storm-petrels are abundant summer residents in the northern
Gulf of Alaska and the estimate by Isleib and Kessel (1973) is that

populations using the waters off the North Gulf Coast probably number in
the millions. Certainly the same estimate is valid for the rest of the Gulf
area west of the Chugach Islands.
The status of these birds relative to their historical abundance cannot be
derived from the existing information. There is strong suspicion that the
introduction of fox on many of the islands in the area during the early part
of this century probably caused a reduction in their numbers. Murie (1959)
said that experience taught him that wings left from fox kills or remains of
storm-petrels in fox droppings could be accepted as evidence of the
presence of a colony. Gabrielson and Lincoln (1959) reported that E. P.
Walker visited the Wooded Islands in 1922 searching for a storm-petrel
colony that had been reported to exist there in 1918. He could not find it
even though he searched diligently. This apparent disappearance was
attributed to the introduction of fox.
There is another factor to consider, however. The limited number of
specimens now available from the Gulf of Alaska indicates that separate
subspecies occupy the eastern and western Gulf of Alaska. The accepted
boundary is somewhere in the vicinity of Prince William Sound. This is an
indication that there has been a hiatus in this area of rather long duration. I
have speculated that this sort of break may be in some way related to the
length of day and a period during the summer when there is little darkness
to cover activities near the colony. Thoresen (1964) and Cody (1973) have
both reported that western gulls (Larus occidentalis) assemble in Cassin's
auklet colonies on moonlit nights to prey on arriving adults. It is likely that
other nocturnal species would provoke the same sort of hunting tactic. A
light-related predation factor implies that the predators rely on sight. Avian
predators are indicated.

Leach's Storm-petrel (Oceanodroma leucorhoa)

Even less well understood than the breeding distribution of the fork-tailed
storm-petrel is that of Leach's storm-petrel.
Bendire (1895) quotes notes from Chase Littlejohn, who found Leach's
storm-petrel to be an abundant breeder on unspecified small islands near
Sanak in 1894. It greatly outnumbered the fork-tailed storm-petrel. On his
visit in 1937 Murie (1959) learned that all of the large colonies of seabirds

that had once existed there were gone. He attributed this to overfishing and
associated perturbation and to the introduction of fox. No systematic
assessment of seabirds on Sanak has been attempted since Littlejohn's time.
No Leach's storm-petrel colonies have been encountered during
reconnaissance surveys of the Gulf of Alaska. Small numbers have been
reported from time to time and while it is very much less abundant than the
fork-tailed storm-petrel, I expect that it will be found in small numbers at
various places in the Gulf of Alaska when it becomes possible to make
more thorough searches. It may occur in remote areas like the smaller
islands scattered throughout the Sandman Reefs—possibly even in large
numbers. On the basis of the Sanak record, we must assume that this storm-
petrel has been greatly reduced in numbers, at least in the western portion
of the Gulf.

Double-crested Cormorant (Phalacrocorax auritus)

The white-crested cormorant, the race of the double-crested cormorant
residing in the Gulf of Alaska, is principally an inhabitant of the marine
environment. This cormorant is a common, but apparently patchily
distributed, resident throughout the northern and western Gulf of Alaska.
Gabrielson and Lincoln (1959) thought that it nested only from Kodiak
Island westward into the Aleutians. However, it probably breeds from
Yakutat Bay westward. Isleib and Kessel (1973) estimated the abundance of
the double-crested cormorant along the North Gulf Coast as several
thousands, about one-tenth as common as the pelagic cormorant. It is the
third most abundant of the four cormorant species nesting in the area. It
occurs as scattered inclusions in many colonies throughout the area, and at
least in the Shumagin Islands, even occurs in some colonies by itself.
There are no data on which to base an estimate of any change in status. It
probably is not much affected by many of the naturally occurring
perturbations.

Brandt's Cormorant (Phalacrocorax penicillatus)

On 22 July 1972, 13 Brandt's cormorants (4 sitting on nests) were found at
Seal Rocks in Hinchinbrook Entrance, Prince William Sound (Isleib and

Kessel 1973). Two years later I positively identified two individuals in
breeding plumage among a mixed group of cormorants in the Chiswell
Islands west of Seward. Are these recent range extensions? Possibly, but I
propose an alternative explanation.
Palmer (1962) showed the distribution of this cormorant as breeding north
to Puget Sound and as a straggler north to Forrester Island, Alaska. This
viewpoint is shared by the American Ornithologists' Union (1957), which
regards the bird as casual as far north as Forrester Island, where this species
was collected by Willet (1918).
Let us look at the other record, the one that is not supported by specimens.
Bent (1964) thought of Brandt's cormorant as a breeding resident of
Forrester Island. Gabrielson and Lincoln (1959) admonished bird observers
to be on the lookout for this particular cormorant in the vicinity of
Ketchikan and Prince of Wales Island. Brandt's cormorant also appears on
the bird list for the Kodiak National Wildlife Refuge as an accidental
visitor.
Early observers like Bent were explorers. They carefully examined and
made notes on all the birds they saw because there was always a chance of a
new discovery. It is also very probable that Bent paid particular attention to
the cormorants when he was at a place like Forrester Island. He would have
undoubtedly been very interested in trying to confirm the presence of the
now extinct Palla's cormorant (P. perspiculatus), as he must have been
aware of Schlegel's (1862-64) list of the birds in the Dresden Museum since
Willet (1914) had recently referred to it. The staffs for the Kodiak and
Aleutian Islands National Wildlife refuges have included some very careful
observers, such as Frank Beals. These men would have noticed the
difference if a new bird such as Brandt's cormorant was seen, verified the
sighting visually, and then noted it in their field diaries. They would not
have bothered to develop the type of proof needed for an undisputable
record, but the bird would have appeared in the refuge bird list (as it does).
The outside coasts of the Alexander Archipelago, Kenai Peninsula, and the
Islands of the Kodiak Archipelago impose some logistical requirements
which discourage all but the most determined birders. Not many have been
able to reach more than very limited segments of the entire coast. Given the
vast distances involved, few of the FWS vessels passing through the area

have had the time to thoroughly examine any cormorant colonies or roosts
bird by bird. Even for those who pause, the ever present swells and the
constant chop of the summer westerlies make positive identification
difficult.
It is possible that Brandt's cormorant has been in the area in small numbers
for a long time, either regularly or intermittently. It could have escaped
observation because of the conditions described above. This species may be
there as a relict, as a pioneer, or only because surplus birds are being pushed
into marginal habitat by population pressures on their main range to the
south.

Pelagic Cormorant (Phalacrocorax pelagicus)

The pelagic cormorant is the most abundant of the four cormorants residing
in the Gulf of Alaska. It is found throughout coastal Alaska south of the
Bering Strait and even in some colonies in the southern Chukchi Sea.
Cormorants have a certain invisibility which is brought about by their
universal presence. This blindness appears to have affected everyone, even
the earliest observers.
The earliest accounts provide a composite picture of the distribution and
abundance of the pelagic cormorant which is very similar to that
encountered today. In southeastern Alaska, beginning at the eastern edge of
the area under discussion, the pelagic cormorant was pictured as the sole
resident cormorant. However, we know from Willet's collection of a
Brandt's cormorant at Forrester Island that this might not be quite true.
From Yakutat Bay westward into the Aleutians this species coexisted with
the double-crested cormorant. In the Western Aleutians there is some
disagreement, but in general it appears to have been accepted that the red-
faced cormorant occurred there along with pelagic and possibly double-
crested cormorants. In the Bering Sea this species coexisted with the red-
faced cormorant.
A number of recent authors (Gabrielson 1940, 1944; Murie 1959; and
others) have considered the pelagic cormorant to be the most widely
distributed and abundant of the four species found in Alaska. Since the
modern picture fits, in a general way at least, it would be easy to conclude

that the species enjoys an unchanged status. There is just a faint suggestion
that this may not be true.
Dement'ev and Gladkov (1966) refer to a great die-off of pelagic
cormorants referred to earlier, in the Commander Islands. Stejneger (1885)
enlarges on this disaster. It is true that Stejneger visited these islands a
relatively short time after the die-off, but he reported that even though the
pelagic cormorants were increasing, "people having seen their former
multitude think that there is no comparison between the past and the
present." Murie (1959) thought that the pelagic cormorant, while numerous,
was outnumbered by the red-faced cormorant in the Aleutians. More
recently there has been the rapid eastward expansion of the red-faced
cormorant. Although it is not possible to determine what the real status of
the pelagic cormorant is relative to its past status, I conclude that during this
century its status relative to that of the red-faced cormorant has declined.

Red-faced Cormorant (Phalacrocorax urile)

The red-faced cormorant, in spite of superficial similarities to the pelagic
cormorant, just does not look the same to an experienced observer.
However, it would have been possible for inexperienced observers in the
days before modern optics to overlook the differences. The problem was
further compounded by the "invisibility" of the ubiquitous cormorants
referred to earlier. Apparent absences or blank spots in their range may not
have been real.
Dement'ev and Gladkov (1966), reporting on the Russian record, stated that
the red-faced cormorant was common in the Commander Islands during the
last part of the 19th century and into the early part of the 20th. Older
authors had also reported it from Kamchatka and the Kurile Islands. Now,
according to Dement'ev and Gladkov, it is an uncommon breeder on
Mednyi Island in the Commander Islands and occurs only as an autumn
visitor to some of the southern Kurile Islands.
Turner (1885) reported that the double-crested cormorant was abundant in
the Near Islands and that the pelagic cormorant was common, but makes no
reference to the red-faced cormorant. One specimen of the latter in the
Leningrad Academy of Science was taken at Attu on 16 September 1844
(Gabrielson and Lincoln 1959), which indicates that they were probably

present during the period reported on by Turner and, therefore, relatively
uncommon. Clark (1911) identified red-faced cormorants only a few times
and in the Aleutians only once, near Agattu. Dall (1874) noted two red-
faced cormorants collected at Amchitka but he (Dall 1873) apparently did
not see any east of Unalaska.
Nelson (1887) apparently found red-faced cormorants breeding on the
Siberian and Alaskan mainlands at either side of Bering Strait, but Bailey
(1948) searched for some sign of their presence and found none. Nelson
(1887) also reported the red-faced cormorant from St. Matthew and St.
Lawrence islands in the northern Bering Sea and from St. Michael and
Nelson Island on the Alaskan coast. Gabrielson and Lincoln (1959) pointed
out that it has not been found breeding north of the Pribilofs since then.
Friedmann (1934) provides support for Nelson by reporting red-faced
cormorant bones from archeological sites on St. Lawrence. Gabrielson and
Lincoln (1959) cited two red-faced cormorants in the Leningrad Academy
of Science which were collected in the Pribilofs in 1843. Dall and Bannister
(1869) reported them to be plentiful on St. George Island. Baird (1869) also
noted their presence in the Pribilofs.
Bent (1964) makes no mention of seeing the red-faced cormorant in the
Aleutians. He gives their breeding range as the Bering Sea region, the
Pribilof Islands, and perhaps the western Aleutians, the Commander
Islands, and the coast of Siberia north of North Cape. The American
Ornithologists' Union (1931) gave their breeding range as the Pribilof
Islands, the Commander Islands, and Siberia north to North Cape.
Murie (1959) found a colony of between 4,000 and 5,000 red-faced
cormorants nesting on Amak Island in 1925. In 1936 he was surprised to
find that the red-faced cormorant was the most abundant breeding
cormorant in the Aleutian Islands. Pelagic cormorants still appeared to be
most numerous, but there were large numbers of nonbreeding birds. In 1936
he located "a good sized colony" of red-faced cormorants at Unga in the
Shumagin Islands. He found about 300 birds starting their nests on 16 May.
In August 1946 Gabrielson (Gabrielson and Lincoln 1959) visited the
colony at Delarof Harbor, Unga, where several thousand cormorants were
observed. From a number of small samples he estimated that the red-faced
cormorants outnumbered pelagic cormorants five to two. In 1973 I observed

about 2,000 cormorants, mostly red-faced, in this colony. Gabrielson also
located them at two other sites in the Shumagins and at Aghiyuk Island in
the Semidi Islands.
Howell (1948) noted only double-crested cormorants at Double Island,
Kodiak. Shortly after that the leaflet, Birds of the Kodiak Island National
Wildlife Refuge (first issued in 1955), listed red-faced cormorants as
common summer residents. The red-faced cormorant was next found at
Katchemak Bay about 1963. Isleib (Isleib and Kessel 1973) first noticed
red-faced cormorants wintering in Prince William Sound in 1969. In July
1972 Isleib and Sowl had found a colony containing 75 nests at Point
Elrington at the western approach to Prince William Sound. By 1974 Isleib
and Haddock (unpublished data, FWS, Anchorage, Alaska) found them east
of the Copper River Delta at Wingham Island.
The relatively rapid expansion of the range and apparent population size of
the red-faced cormorant is remarkable. But has this been a real expansion
into vast stretches of new territory? The record in the literature which I have
summarized shows, I think, something else. We can demonstrate a historical
range for the red-faced cormorant that extends on the Asiatic Coast from
North Cape, Siberia, south to the Kurile Islands, the entire Aleutian Arc
including the Commander Islands, all the Bering Sea islands north to
Bering Strait, Norton Sound, Nelson Island, and the islands south of the
Alaska Peninsula at least as far east as Kodiak Island. The recently
occupied coast from Cook Inlet to the Copper River may represent a real
range extension. The breeding range of this species at the present time does
not include parts of its historical range west of the Commander Islands or
north of the Pribilof Islands.
The fragmentary record appears to show a long-term perturbation in the
range and populations of the red-faced cormorant that covers at least 100
years. I believe that we are probably seeing a recovery of lost range and a
return to something resembling a former distribution and abundance.
What caused the perturbation? I am not prepared to answer this question,
but there are two occurrences which I find suggestive.
It is interesting to note (Dement'ev and Gladkov 1966) that on the
Commander Islands the red-faced cormorant was most abundant during the
first 50-odd years after the pelagic cormorants had been wiped out in the

winter of 1876-77. Perhaps some clues are to be found in the interactions
between these similar species.
It does not appear that the introduction of fox could have been a causative
factor. The first observations of population expansion were noted almost
concurrently with the heyday of the fox-farming industry. Because of its
choice of nesting habitat (very steep cliffs), this cormorant would not have
been affected by predators except for the one that went into a very rapid
population decline at a time that would fit—the Aleut.
Jochelson (1968) and Hrdlicka (1945) summarized references to Aleut
clothing in the diaries and reports of early Russian visitors to the Aleutian
Islands. Evidently Aleut women sometimes wore a long, robe-like parka
made of harbor seal (Phoca vitulina) skins or, for women of high rank,
parkas made of sea otter (Enhydra lutra). The men in almost all reports
were said to have worn bird-skin parkas; puffins and guillemots appear to
have been preferred, but cormorants were sometimes used. It took about 40
puffin skins to fabricate a parka and a man evidently needed from one to
three of these garments each year.
Sea otter populations were drastically reduced by Russian hunters. Rats
were introduced to the Aleutians very early during the Russian period and
must have had a substantial impact on populations of tufted puffins and
guillemots. The introduction of fox would have had a further impact on
burrow-nesting birds. Turner (1885) noted that Aleuts in the Near Islands
kept the fox confined to Attu so that they could keep the fox away from the
birds on Agattu. This is evidence of an Aleut recognition of serious
competition. Could cormorants, particularly red-faced cormorants, have
been preferred sources of fiber? Were Aleuts forced to rely more heavily on
cormorant skins as puffin and guillemot numbers were reduced by rats and
fox and sea otters by men?
Whatever the cause and effect, the status of red-faced cormorants now
appears to be better in the Gulf of Alaska than for at least the last 100 years.

Glaucous-winged Gull (Larus glaucescens)

The glaucous-winged gull is apparently one of the more successful seabirds
breeding in the Gulf of Alaska. While it is outnumbered (both locally and in

total abundance) by the black-legged kittiwake, it is generally the most
commonly seen and most uniformly distributed gull in the Gulf of Alaska.
Murie (1959) called it the common breeding gull about the Alaska
Peninsula. Cahalane (1943, 1944) considered it to be numerous to abundant
around Kodiak and in the Shelikoff Strait area. Gabrielson (1944) reported
that it could be seen in small numbers everywhere. Most recently, Isleib and
Kessel (1973) reported it to be an abundant resident in the north Gulf Coast
area. My own experience would confirm these observations.
This gull appears to use a wider variety of nesting sites than some others
(Gabrielson and Lincoln 1959). Except where man's activities have created
new food sources, there appears to be a close link between the location of
glaucous-winged gull colonies and those of murres, kittiwakes, and
cormorants. Swartz (1966) found that during the breeding season glaucous-
winged gulls at Cape Thompson derived almost all of their food from murre
eggs and chicks. I have noted small numbers of these gulls nesting, usually
on turf near the tops of cliffs, in most colonies of favored prey species.
The glaucous-winged gull is the principal scavenger throughout much of
coastal south-central Alaska. This has sometimes resulted in the
development of large concentrations near canneries and, more recently, near
dumps.
Two glaucous-winged gull concentrations stand out in the northern Gulf of
Alaska. One of these is on Egg Island at the western end of the Copper
River Delta. Patten (1976) estimated that this colony contained 10,000-
12,000 gulls in 1975. At times it appears to spread onto nearby
Hinchinbrook Island. M. E. Isleib (personal communication) has estimated
its size as high as 25,000 gulls. The other large concentration is on the
Susitna Flats across Cook Inlet from Anchorage. This colony, or colony
cluster, may be larger than the one at Egg Island. There are no other known
colonies even approaching these in size. Most colonies range between a few
pairs and 2,000-3,000.
Glaucous-winged gulls do not appear to have had any great changes in
population that can be detected from the literature. There have almost
certainly been local fluctuations in the number of breeding birds as food
supplies, such as canneries and dumps, have appeared or disappeared in an
area. Long-term changes in salmon runs have undoubtedly had an impact as

well. One other change, the reduced level of egging, has undoubtedly had
an effect also. Along the Alaska Peninsula and in the Shumagin Islands,
cannery workers of Filipino heritage and fishermen who have a strong Aleut
heritage still harvest gull eggs for food. However, this activity is much
reduced from what it must have been.

Herring Gull (Larus argentatus)

The herring gull is a resident of Upper Cook Inlet and is found up and down
the coast from Prince William Sound to the Alaska Peninsula. Not too much
was learned about it during the recent FWS reconnaissance. Williamson and
Peyton (1963) reported the interbreeding of herring gulls and glaucous-
winged gulls in this area. This interbreeding has resulted in a situation in
which assignment of these gulls to one group or another in the field can be
rather arbitrary. The result has most often been that field observers tend to
lump them with glaucous-winged gulls unless their herring gull
characteristics are obvious. Specimens collected by Williamson and Peyton
(1963) indicate that herring gulls have the edge in numbers in Upper Cook
Inlet.

Black-legged Kittiwake (Rissa tridactyla)

The black-legged kittiwake is the most abundant gull in the northern and
western Gulf of Alaska. Colonies of this species can be found throughout
the entire area, and range in size from a few pairs (Class I) to more than
100,000 birds (Class V). They may be found in essentially pure colonies,
but are often found sharing colonies with murres.
The center of abundance for breeding black-legged kittiwakes in the Gulf of
Alaska is in the Semidi Islands, where Palmer Sekora (U.S. Bureau of Sport
Fisheries and Wildlife 1973) estimated that there were 426,000 breeding
kittiwakes in 1972. He located kittiwake colonies at eight sites, ranging in
size from 1,000 to 109,000 nesting birds. The size of the average colonial
site was 27,000 birds. Ten sites were Class IV in size and one was a solid
Class V.
The easternmost known colony in the northern Gulf of Alaska is at
Wingham Island. Up to 1973, 22 colonies had been located in Prince

William Sound. The largest of these contained only 5,636 nests in 1972
(Isleib and Kessel 1973). Class IV or larger colonies are found at Cape
Resurrection, the Barren Islands, Chisik Island, Boulder Bay and Cape
Chiniak on Kodiak Island, and at Delarof Harbor and the Haystacks in the
Shumagin Islands. It is interesting to note that Gabrielson (1940) considered
Whale Island to be one of the largest known kittiwake colonies in Alaska.
He stated that there were many thousands of pairs extending over a mile or
more of cliff. He saw a second site which he did not visit but looked equally
large. A photograph in an article by East (1943) also indicated the presence
of a large colony. C. J. Lensink (personal communication) estimated that
there were about 100,000 kittiwakes in the colony in 1956. When last
visited by Vernon Berns (personal communication), this colony contained
only 3,000 birds. It is also of interest that Gabrielson (1940, 1944) did not
notice either the kittiwakes or the murres now breeding on Nord Island in
the Barren Islands or the kittiwakes on East Amatuli Island.
Whale Island and possibly the colonies in the Barren Islands give evidence
of local population fluctuations, but for the most part I have not found an
indication of a major perturbation over the past 40 years. Before 1936, the
record is too fragmentary to allow an assessment.
One of the interesting aspects of kittiwake ecology in the Gulf of Alaska is
the common occurrence of breeding failure. David Snarski (December 1943
Quarterly Progress Report, Alaska Cooperative Wildlife Research Unit,
University of Alaska) observed breeding failure on colonies in the Tuxedni
National Wildlife Refuge in 1970 and 1971 and obtained circumstantial
evidence of another failure in 1972. In 1973 all of the breeding cliffs were
occupied and nesting was successful. Whatever the cause of these periodic
failures, they do not yet appear to have had a permanent impact that we are
able to measure.

Red-legged Kittiwake (Rissa brevirostris)

Red-legged kittiwakes are not now known to breed in the western Gulf of
Alaska. Turner (1886) stated that he saw a few at Sanak in 1878. We also
have Stejneger's (1885) statement, that "red-legged" kittiwakes nest from
Bering Island to Sanak. Friedmann (1937) reported two humeri from
Kodiak Island middens. During the summer of 1976, two birds were

observed off Kodiak Island by Irving M. Warner (personal communication),
and one at 158°W and 54°30'-54°20'N south and east of the Shumagin
Islands (Patrick J. Gould, personal communication).
Turner (1885) listed the red-legged kittiwake as abundant and breeding in
the Near Islands. Turner (1886) also stated that he had seen quite a number
about a cliff back of the village on Akutan Island in 1878. He added that to
the westward this kittiwake was more abundant than the black-legged
kittiwake. Murie (1959) expressed the opinion that Turner had confused the
short-billed gull with the "short-billed" kittiwake. Clark (1911) also
reported that he had seen the red-legged kittiwake in small numbers near
Unalaska and that they became progressively more common west to the
Near Islands. Nelson (1887) reported seeing large numbers of red-legged
kittiwakes at Unalaska. Murie (1959) and Gabrielson (1940, 1944) did not
see any red-legged kittiwakes in the Aleutian Islands. The species has
recently been discovered breeding at Buldir and Bogoslof islands (G.
Vernon Byrd, personal communication).
Is it possible that we have here another species which is exhibiting a
response to some unknown long-term perturbation? The suggestion that
such an event has occurred is faint, but it is there. Do we have in the red-
legged and black-legged kittiwakes an example of yet another congener pair
that has been affected by some perturbation in which one was affected
positively and the other negatively? Clark (1911) reported small numbers of
black-legged kittiwakes to go with large numbers of red-legged kittiwakes
in the Near Islands, which is the reverse of the current situation.

Arctic Tern (Sterna paradisaea)

Gabrielson and Lincoln (1959) attribute to the Arctic tern the most
extensive range of any Alaskan water bird. It is found in suitable habitat
everywhere north of Tracy Arm in Southeastern Alaska. Murie (1959) stated
that he found it nesting at suitable sites everywhere he went. Isleib and
Kessel (1973) considered it to be an abundant breeder in Prince William
Sound and along the northern Gulf Coast.
The Arctic tern was observed in FWS aerial surveys in Prince William
Sound, and surveys in July and August 1972 provided an estimate of 45,000
terns in the Sound (Isleib and Kessel 1973). On the other hand, tern

colonies were located only rarely in the FWS colony surveys before 1975.
This is, however, a reflection of the equipment and methods used and not of
the abundance of terns.
From the fragmentary data available, it is not possible to detect changes in
Arctic tern status at the present time. We have to assume that the
widespread introduction of fox had at least local impact. Although this tern
uses a wide variety of nesting sites, it tends to nest on flat sites where
access by mammalian predators is easy.

Aleutian Tern (Sterna aleutica)

No Aleutian tern colonies were discovered in the Gulf of Alaska area during
FWS colony surveys in the early 1970's. This is again a reflection of the
fact that surveys were not designed to locate tern colonies. Aleutian terns
were encountered at least twice, once during late March 1972 in Hawkins
Cutoff, Prince William Sound, and again when two birds were noted
offshore from the Katmai National Monument on 30 May 1973 (L. W.
Sowl, personal observations).
The type specimen of the Aleutian tern and a single egg were collected at
Kodiak Island on 12 June 1868 by Bischoff (Coues 1874). Fisher
(Gabrielson and Lincoln 1959) collected four more eggs in 1882. The bird
was not found breeding there until Howell (1948) found a colony of 50
pairs at Bell's Flats in 1944. Walker (1923) found them nesting on the Situk
River, Yakutat, in 1917 and shortly thereafter saw them at the Alsek River
Flats. He also reported that D. H. Stevenson of the Bureau of Biological
Survey had told him that they nested on the Isanotski Islands at the end of
the Alaska Peninsula. This latter report was the only one from the Aleutian
Island chain for many years. Isleib and Kessel (1973) considered it an
uncommon local breeder in the northern Gulf of Alaska. Isleib estimated its
population at a few hundred pairs on the Copper River Delta in May 1973
and 300-500 birds in June 1970. He also reported that they appeared more
or less regularly near Controller Bay and off the Situk River.
In recent years Aleutian terns have been seen with increasing frequency in
many places in western Alaska and the Aleutian Islands. This is probably
partly due to the increasing level of field work. At Amchitka Island the

several colonies that have been found in recent years are almost certainly
exhibiting a response to the removal of fox from the island.
Although there is no way of determining what the past status of the Aleutian
tern has been in the Gulf of Alaska area, it has been there in small numbers
since it was first discovered on Kodiak. It has probably not been abundant
at any time and may have suffered a long-term decline brought about by the
introduction of fox.

Common Murre (Uria aalge)

The common murre is resident in the northern and western Gulf of Alaska
from Pinnacle Rock, Kayak Island, westward. East of Cook Inlet colonies
are located at Wingham Island, the Martin Islands, Middleton Island,
Porpoise Rock in Hinchinbrook Entrance, Barwell Island/Cape
Resurrection, the Chiswell Islands, the Barren Islands, and Chisik Island.
For some reason, the islands of the Kodiak-Afognak Archipelago do not
host any known major murre colonies. There is also a rather large gap
between the Chisik Island colony and the next major colony at Oil Creek
west of Puale Bay. Directly west of Oil Creek is another colony at Cape
Unalishagvak. Both of these latter colonies are Class V and they are the first
colonies of this size to be encountered in the Gulf of Alaska. West of these
colonies the next large colony is at Atkulik Island. To the south, midway
between the last-named colonies, lies the major composite murre colony in
the Semidi Islands. These sites make up the only Class VI colony in the
Gulf of Alaska. Westward, the next major colony, a Class V, is at Spitz
Island south of Mitrofania Island. In the Shumagin Islands one Class V
colony is at Karpa Island, and lesser colonies with large murre components
are found at the Haystacks, Castle Rock, and Bird Island. Only minor murre
colonies are found between the Shumagin Islands and the end of the Alaska
Peninsula.
Gabrielson and Lincoln (1959) were aware only of the colonies at Cape
Resurrection (which Gabrielson considered to be large), at the Chiswell
Islands, and at Chisik Island for the area from Cook Inlet east. Gabrielson
visited the Barren Islands on 13 June 1940 and apparently did not notice the
present murre colonies, both Class IV, at East Amutuli (an island which he
visited) and Nord Island.

Gabrielson (Gabrielson and Lincoln 1959) found a few small colonies at
Kodiak, mostly on small offshore islands. Gabrielson found common
murres to be abundant in the Semidi Islands and stated that there were no
notable colonies in the Shumagins, although on his return to the Shumagins
in 1949 he did find a fairly large colony at the Haystacks. That size
description would fit the colony that is there now. He obviously did not see
the other colonies. Rausch (1958) reported murres from Middleton Island.
There is quite a difference between the distribution of murres as we know it
today and the way Gabrielson and Lincoln pictured it. Why does this
difference exist? There are two possible answers: either the number of
colonies has increased, or the coverage of colony locations has improved.
The latter case, at least, is established. I must confess to being puzzled by
the way Gabrielson was able to move about close to what are now known to
be sizeable colonies without seeing them, those in the Barren Islands and
the Shumagin Islands in particular. Perhaps this represents the vague
outlines of yet another population change.
The center of abundance for murre distribution in the Gulf of Alaska today
is from Paule Bay west to eastern Shumagin Islands. The Semidi Islands are
the heartland of this area of maximum abundance. We have no definitive
data on species composition of these colonies. Common murres
undoubtedly dominate in most of the colonies; the only ones where we
know of a sizeable thick-billed murre component are in the Shumagin
Islands.

Thick-billed Murre (Uria lomvia)

Thick-billed murre population information cannot be separated from that of
the common murre on the basis of existing data. A direct assessment of
present-day status is not possible. After reviewing what we know about
their distribution, I suggest a way to examine the question indirectly.
The thick-billed murre is found in colonies with the common murre from
Middleton Island westward; Rausch (1958) noted about 400 murres at
Middleton Island and observed that the thick-billed murre outnumbered the
common murre by several times. Isleib and Sowl (FWS, unpublished data)
saw a thick-billed murre mixed with common murres at Porpoise Rock in
July 1972. Isleib and Kessel (1973) expressed the opinion that small

numbers of thick-billed murres will be found in most common murre
colonies in the northern Gulf of Alaska when it is possible to survey these
colonies in detail. Karpa Island had a significant component of thick-billed
murres in June 1973, and they constituted 40% of the colony at the
Haystacks (L. W. Sowl, unpublished data).
Bent (1963) reported that many thick-billed murre eggs have been taken by
collectors at Round Island in the Shumagin Islands. Dall and Bannister
(1869) reported a thick-billed murre that was taken at Kodiak in 1867.
The Gulf of Alaska is at the periphery of the breeding range of the thick-
billed murre. While it probably occurs in mixed colonies with the common
murre throughout this area, the thick-billed murre is much less abundant.
Occasionally in the Gulf of Alaska, a colony will be occupied
predominantly by the thick-billed murre. Gabrielson and Lincoln (1959)
noted that the thick-billed murre outnumbered the common murre in many
colonies in the Aleutians and that it became progressively more common at
higher latitudes.
We have almost no data relative to the species composition of murre
colonies in the Gulf of Alaska. Until we do it will not be possible to fully
understand the population status of the thick-billed murre. It appears that
changes in the species composition of murre colonies in the Bering Sea may
be an indicator of perturbation. The data for the Gulf of Alaska are still too
fragmentary to provide any indication of whether or not the same indicator
would work there. Close monitoring of the Shumagin Islands colonies over
a number of years might produce the answer.
Earlier in this paper I noted the dramatic changes in species composition of
murre colonies on Walrus Island. Gabrielson and Lincoln (1959) also
commented on this well-documented and anything but static situation.
Investigators who visited this island during 1976 reported seeing no murres
on the island and only small numbers on offshore rocks. James Bartonek
(personal communication) said that this situation has prevailed for several
years.
There is an indication that a similar population fluctuation and change in
species composition of murre colonies have also occurred on St. Matthew
Island. Bent (1963) found mostly common murres and few thick-billed

murres at St. Matthew. Hanna (1916) saw only thick-billed murres. Later,
Gabrielson (1941) found this to be true in 1940.
Dramatic fluctuation in murre populations may be common and, at least in
some cases, the two species may be affected differently. Perhaps this
phenomenon has potential for providing us with an indicator of some
natural perturbations.
Peterson and Fisher (1955) expressed the opinion that thick-billed murres
arrived at the nesting ledges later than the common murre and had to take
the sites that were left. Tuck (1960) reported data from the western Atlantic
showing that thick-billed murres arrive later than common murres. On the
other hand, Belopol'skii (1961) reported data showing that the two species
arrive on breeding colonies in East Murman simultaneously. At Cape
Thompson, Swartz (1966) found that thick-billed murres arrived about a
week before common murres. The date of arrival, while perhaps a
contributing factor, is probably not decisive. Interspecific competition of
another sort is indicated.
In mixed murre colonies where there are large numbers of common murres,
this species occupies the choice nesting sites. Thick-billed murres are
usually left with the narrower ledges while the common murres occupy the
longer, broader ledges (Belopol'skii 1961). The broader ledges have lower
chick and egg mortality (Spring 1971). Spring also noted that thick-billed
murres are excluded from the centers of mixed colonies. Johnson (1938)
found that this contributes to higher losses of eggs to predators and to the
loss of other social benefits of occupying the colony center (Johnson 1941).
Kozlova (1961) said that during the occupation of a colony there is a sharp
competitive struggle between the two species. In the end thick-billed murres
are pushed out to the periphery of the colonies or left with narrow ledges or
other equally unfavorable sites. Spring (1971) studied the functional
anatomy of both species and concluded that the common murre is more
successful in these encounters because it has a more upright gait and greater
agility than the thick-billed murre.
It follows that in a portion of their respective ranges, where the two species
overlap and where there is an equal chance that either common murres or
thick-billed murres will dominate a given colony, the common murre
dominates. I conclude from this that where there are dramatic changes in

species composition of murre colonies, such as at Walrus Island, it is
probably because the common murre has been greatly reduced in numbers
at the colony.
Spring (1971) concluded that the common murre is well adapted to pursuit
and capture of pelagic fishes and that the thick-billed murre is better
adapted for deep diving and the capture of benthic fishes and pelagic and
benthic invertebrates. Having greater latitude for food selection, the thick-
billed murre would have a greater tolerance for ecological perturbations
affecting the available food supply. The common murre has an advantage
when pelagic fishes are available but cannot switch to the other foods as
readily as can the thick-billed murre. The low density of pelagic fishes in
high arctic areas probably also accounts for the greater success of the thick-
billed murre at higher latitudes relative to common murres.
Belopol'skii (1961) presented data from East Murman which indicates that
the common murre restricts its diet almost entirely to a small number of fish
species. Swartz (1966) found strong indications that there were significant
differences in the food preferences of the two species of murres. Thick-
billed murres made much greater use of invertebrates. Bédard (1976)
asserted that it is well known that the common murre is quite partial to
zooplankton. So again the issue is not clear-cut.
The situation is, of course, much more complex than I have portrayed it.
Nonetheless, I think that it offers potential for use as a tool in assessing
population change and perturbations in the food supply which should be
studied quite closely.

Pigeon Guillemot (Cepphus columba)

Gabrielson and Lincoln (1959) noted that the pigeon guillemot was one of
the most regularly observed birds in Alaskan waters. It is found everywhere
throughout the northern and western Gulf of Alaska area, with only a few
understandable and relatively small blanks, such as in the silty waters of
Upper Cook Inlet. Because it obviously lacks the breeding murres' need for
close contact with its nearest neighbors, it is able to exploit the available
nesting habitat to the fullest. It seems that literally every bit of suitable
nesting habitat is normally occupied.

Because of the dispersed way in which it breeds and because it does much
of its feeding in the onshore zone (which is hazardous for boats) the pigeon
guillemot is an almost impossible species to inventory by standard methods.
There is no evidence that the pigeon guillemot has been greatly affected by
any major perturbation. Because of its choice of nesting habitat, it is
probably subject to the attack of only one egg predator, the rat. Because of
its loose social structure and the way it selects nesting sites, eggs and young
do not sustain loss from panic flights. Its dispersed distribution should
insure that man-made impacts such as oil spills will have limited impact.
The population levels of the pigeon guillemot are probably relatively very
stable. The widespread introduction of the rat to most of its nesting range
undoubtedly had impact, but this impact has gone undocumented. It would
be interesting to follow the response of guillemot populations on islands
where rats had been totally removed, if that ever becomes more than a
dream.

Marbeled Murrelet (Brachyramphus marmoratus)

The marbled murrelet apparently breeds throughout most of the northern
and western Gulf of Alaska. This apparently is a necessary condition
because to date, at least in this part of Alaska, we can only guess where and
under what conditions this murrelet breeds.
In some relatively sheltered waters like Prince William Sound, where
marbled murrelets were estimated to number about 250,000 in 1972 (Isleib
and Kessel 1973), they are the most abundant seabirds. We know from
Dixon (1908) and Grinnell (1910) that this has been so in Prince William
Sound since the beginning of the century. We know also that the type
specimens came from there as well (Stresemann 1949), which is not
necessarily an indication of abundance but is suggestive of their abundance
relative to species not collected.
Gabrielson (Gabrielson and Lincoln 1959) found marbled murrelets
common near Yakutat, in Prince William Sound, in Resurrection Bay, and at
Kodiak, and reported seeing them at the Chiswell Islands and at Chignik
and Pavlof Bay on the Alaska Peninsula. Cahalane (1943, 1944) found them
to be common in Kupreanof Strait, and along the Alaska Peninsula north of

Katmai Bay. Murie (1959) found them all along the Alaska Peninsula. My
own field notes from 1973 indicate that the only place where they were
common along the Alaska Peninsula was at Wide Bay.
We can sample marbled murrelet numbers by using standard transect
methodology; however, I have some very serious reservations about our
ability to convert these data into a population estimate. This is not an
unusual assessment for Alaskan seabirds in general, but I think it is
particularly apropos to this species.
We are still able only to guess at where the marbled murrelet nests and we
have not a clue as to what sort of nesting strategy they pursue. I am not
prepared to accept, on the basis of one North American record (Binford et
al. 1975), that tree nesting is its habit throughout its range. What has been
proved is that the marbled murrelet nests in trees and not, as these authors
would have us believe, that it does not nest on the ground. It has become
rather fashionable to ignore the Chichagof Island record (a ground nest), but
it has not been discredited. The color of the Chichagof egg differs from that
of the Big Basin egg, but does agree with the one taken from an oviduct by
Cantwell (Gabrielson and Lincoln 1959). My own experience leads me to
believe that tree nesting, if it occurs, is not the common habit of marbled
murrelets nesting in the Prince William Sound region.
After many hours of observing marbled murrelets over a period of several
years, I am intrigued by a number of things. These birds, as often as not,
appear to be clustered in "pairs" as they feed. This occurs even at what
should be the height of the breeding season. On several occasions I have
noted a very pronounced evening flight of these birds from gathering areas
on the water up into the surrounding mountains at sunset. This has moved
me to wonder if their nesting strategy includes incubating at night but less
than full-time attendance on days when the eggs can be warmed by the sun.
We know that periodic egg-neglect is an aspect of storm-petrel behavior
(Pefaur 1974). Is this behavior also possible on a more regular basis in an
alcid? If so, it would certainly help explain why nests are hard to find.
It is apparent that more needs to be known about the population dynamics
and life history of the marbled murrelet before we can make a proper
estimate of its abundance. In spite of the fragmentary record, I conclude

that the marbled murrelet probably enjoys the same relative abundance and
distribution that it did at the beginning of the century.

Kittlitz's Murrelet (Brachyramphus brevirostris)

The Kittlitz's murrelet is not as abundant as the marbled murrelet, but
locally it is sometimes found in large numbers. FWS surveys conducted
during July-August 1972 provide an estimate of 57,000 murrelets of this
species in Prince William Sound. Almost a fifth of these were concentrated
in Unakwik Inlet above Unakwik Reef. Even more interesting, about 2,500
of these birds were concentrated in one loose flock.
In addition to Unakwik Inlet, Kittlitz's murrelets concentrate in College
Fjord in Prince William Sound and in the waters fronting the Bering-
Malaspina ice-fields (Isleib and Kessel 1973). Common as they are in these
waters, this species is supposed to be even more abundant at Glacier Bay.
The common feature of these waters is the amount of ice that can be found
below their tributary glaciers.
The Kittlitz's murrelet is apparently distributed from LeConte Bay, east of
Petersburg, Alaska, north to Point Barrow and west across the Aleutians to
Attu, where Murie collected a pair (Gabrielson and Lincoln 1959). I once
flushed a murrelet from an area of tread and riser topography near the top of
the highest point on Kiska Island in heavy cloud cover, and although I could
not see this bird well, I thought it to be of this species. From the range
description in Gabrielson and Lincoln (1959) and Udvardy's (1963) range
map, it is apparent that the distribution of this species is rather patchy, but I
suspect that for the more mountainous part of its range this is more apparent
than accurate. The record is too fragmentary to allow an assessment of any
change in status during the historical period.

Ancient Murrelet (Synthliboramphus antiquus)

Chase Littlejohn (Bendire 1895) spent the spring and summer of 1894
collecting eggs on islands south of the Alaska Peninsula. He has left us a
detailed record of what he saw but not where he saw it. Bent (1963) stated
flatly that the site of his collecting was Sanak Island and this has common
acceptance. Several things in his account point to a site which was a small

island with several peers close by, but this could not have been Sanak. It
could have been an island in the Sanak Island group or it could equally well
have been somewhere in the Sandman Reefs. Unfortunately, because of this
the record is clouded. There has never been anything approaching a survey
of the southern half of the Sandman Reefs. We do not know what breeding
colonies are there.
At any rate, Littlejohn told of the large numbers of Leach's storm-petrels,
fork-tailed storm-petrels, auklets (of which only Cassin's is specifically
identified), and ancient murrelets which occupied a large number of small
islands. He could not calculate the number of breeding murrelets on his
small island, the size of which I interpret to have been of the same order of
magnitude as two others which he estimated were about 2 acres. He does
say that the murrelets must have numbered several thousand and could, if
left alone by the Aleuts, have quickly grown too numerous for the island to
accommodate.
Murie (1959) made a brief visit to Sanak in 1937 and learned that there
were no longer any large colonies of seabirds. He attributes this to
exploitation of the fisheries and to the fox-farming industry. Littlejohn told
of the repeated visits of Aleuts to his small islands, where they took
hundreds of birds each time and all of the eggs they could find. This kind of
activity could not help but disrupt the breeding on these islands.
Littlejohn's description of the ancient murrelet's nest leaves little doubt that
the birds could be reached by fox or rats with ease. The birds showed no
particular care in selecting a nest site and often worked their way back no
more than about a meter into the dead vegetative cover from preceding
years, where they scratched out a shallow nest.
There are few records of the ancient murrelet from the northern and western
Gulf of Alaska. Friedmann (1935) reported the collection of a series of eggs
in 1884 on Kodiak Island. Chase Littlejohn (Bendire 1895) collected eggs
from somewhere in the Sanak Group in 1894. In 1908 Dixon (Grinnell
1910) saw a bird in Port Nellie Juan. Several were seen by Jaques (1930)
near Belkofski in May 1928. Gabrielson collected one bird at Cordova in
September 1941 and another at the Chiswell Islands in July 1945
(Gabrielson and Lincoln 1959). He saw numerous flocks in the Gulf of
Alaska on 30 July of an unnamed year. In 1943, he would have been near

Cape Spencer on that date. In 1945 he would have been near the Chiswell
Islands. In either case, he was probably somewhere in Blying Sound.
The ancient murrelet is relatively uncommon but regularly observed in the
inshore waters along the outer coasts of the islands fronting Prince William
Sound. FWS surveys in July-August 1972 provided an estimate of almost
1,000 birds, mostly in nonbreeding plumage, along the outer coast of Prince
William Sound (Isleib and Kessel 1973). Small numbers were found
feeding close to the Wooded Islands on 24 July (my personal observation).
Rausch (1958) saw a few off Middleton Island in 1956. Isleib (Isleib and
Kessel 1973) saw 400-500 widely distributed at the mouth of Yakutat Bay
in July and August 1968. The only large numbers of ancient murrelets
encountered on the FWS survey of the Alaskan Peninsula in 1973 were in
the Shumagin Islands. They were very common in East Nagai Strait on 9
June and more than half of the 1,300 seabirds per square nautical mile
encountered between Little Koniuji and Chernabura Islands on 11 June
were ancient murrelets. At Nagai Island an estimated 5,000 ancient
murrelets were observed in the west bay at Pirate Shake, and later (on 19
June) several were observed in the vicinity of Midun Island (FWS,
Anchorage, Alaska, unpublished data).
On the basis of the observations recounted above, I have to conclude that
ancient murrelets are fairly regularly, if patchily, distributed throughout the
northern and western Gulf of Alaska. I do not believe that the void in their
range shown for the northern Gulf of Alaska by Udvardy (1963) is correct.
Several colonies are there, awaiting discovery.
Ancient murrelets are not abundant in the Gulf of Alaska but they are
certainly more numerous than we have been able to prove. It is not possible
to tell from the existing data whether they were once more abundant than
they are now. I suspect, on the basis of the Sanak Island experience, that we
can conclude that this species has been reduced in number by various of
man's activities.

Cassin's Auklet (Ptychoramphus aleuticus)

Cassin's auklet is a very uncommon bird in the northern Gulf of Alaska. In
the western Gulf it is more common, particularly from the Shumagins west.

This auklet apparently once bred in great numbers on islands in or near the
Sanak Group where Chase Littlejohn (Bendire 1895) found them to be
twice as numerous as the ancient murrelets. Murie (1959) did not find them
there.
Littlejohn began encountering Cassin's auklets at sea some 290 km
southeast of Unga, Shumagin Islands. Murie (1959) encountered them near
the Shumagins in May 1937. During the FWS 1973 reconnaissance survey
of the Alaska Peninsula, these auklets were not encountered (or at least not
identified) until we reached the vicinity of Unga Strait where we saw a few
in mixed flocks with other murrelets and auklets. They were most numerous
in East Nagai Strait. We encountered them only twice in a situation which
indicated they might be breeding—on Hall and Herendeen islands on the
north end of Little Koniuji Island.
Murie (1959) considered Cassin's auklet to be no longer common west of
Kodiak. In Gabrielson's many voyages through the northern and western
Gulf of Alaska he encountered them only twice, once off Cape Spencer and
once in the Chiswell Islands.
Thoresen (1964) commented that throughout the northern part of its range
the Cassin's auklet has become gradually less frequent. Although there are
no data to dispute this, I believe, as do Isleib and Kessel (1973), that they
are more numerous than observations would indicate, and I would apply
this to the entire area. There are certainly colonies remaining in the
Shumagin Islands, and quite probably along the south coast of the Kenai
Peninsula. When it is possible to fully explore the Sandman Reefs there is a
good probability that they will be found there.
We can only guess at the reasons for their decline. Bendire (1895) and
Murie (1959) have described some contributing factors.

Parakeet Auklet (Cyclorrhyncus psittacula)

Gabrielson and Lincoln (1959) described the parakeet auklet as the least
colonial of any of the Alaskan auklets. They also considered the Aleutian
Islands to be its principal nesting grounds. There are old records of breeding
parakeet auklets from Kodiak (Friedmann 1935) and Little Koniuji (Bean

1882). Grinnell (1910) reported two that were seen on Green Island, Prince
William Sound, and several more that were seen near Knight Island.
Murie (1959) did not see any parakeet auklets near Kodiak and Afognak
islands which he considered to be the eastern part of their range. He did not
think they were abundant anywhere along the Alaska Peninsula. He found a
few near Sutwik Island in May 1936 and then noted that they were fairly
common near the Shumagins in May 1937.
Gabrielson found this species to be quite numerous on the north side of
Chowiet Island in the Semidi Islands in 1945 (Gabrielson and Lincoln
1959). He also saw numerous individuals in Marmot Strait and saw one in
the Chiswell Islands during the same year. David Roseneau (Isleib and
Kessel 1973) found hundreds close to East Amatuli Island in the Barren
Islands in 1965.
During FWS colony surveys, parakeet auklets have been found in close
proximity to six seabird colonies in Prince William Sound. During the July-
August 1972 surveys, they were estimated to number about 3,000 in the
Sound. They have also been found closely associated with Chisik Island
(David Snarski, personal communication), the Chiswell Islands, Nord and
Sud islands in the Barrens, Sea Otter Island, and Central and Long islands
along the Alaska Peninsula. They were most numerous in the Shumagin
Islands, where they were found near Castle Rock, Hall (9,000), Herendeen
(3,000), Atkins (more than 5,000), and Little Koniuju islands. They were
again encountered south and west of Cold Bay at High, Fawn, Let, Amagat,
Umga, and Patton islands. Many of these islands are in the north half of the
Sandman Reefs, the only portion where any attempt has been made to
survey seabird colonies.
The parakeet auklet may not be abundant anywhere in the Gulf of Alaska
but, based on the numbers of places it has been seen in recent years, its
population appears to be well dispersed and probably doing very well. This
auklet is most abundant from the Shumagin Islands westward. It is almost
certainly more numerous than has been thought. Its habits are secretive
enough so that it could easily escape notice.
Because the parakeet auklet nests predominantly under boulders, it
probably was not much affected by fox. Rats would certainly have reduced
its numbers wherever these were introduced into its breeding habitat. We

have no data to tell us whether there may have been population fluctuations
in the past, but there undoubtedly were at least minor ones locally after rats
were introduced.

Crested Auklet (Aethia pygmaea)

Udvardy (1963) shows the breeding range of the crested auklet as extending
from southern Kodiak Island westward. Within the northern and western
Gulf of Alaska, it is certainly most abundant in the eastern Shumagin
Islands.
Isleib saw this auklet in Prince William Sound 3 times during the winter of
1972-73. These are the only records he was aware of for that area (Isleib
and Kessel 1973). David Roseneau (Isleib and Kessel 1973) saw several in
Amatuli Cove, Barren Islands, in June 1965. I observed one in the vicinity
of Cape Spencer in August 1973.
Friedmann (1935) listed the crested auklet as a breeding bird at Kodiak, but
considered it to be much more abundant as a wintering bird. Townsend
(1913) has provided us with a vivid description of the myriads of crested
auklets he encountered at Yukon Harbor, Little Koniuji Island. Gabrielson
and Lincoln (1959) noted large numbers of crested auklet around Simeonof
and Bird islands in the Shumagin Islands in 1946 and stated that the Yukon
Harbor colony was still thriving.
Crested auklets were not encountered on the 1973 FWS reconnaissance
survey until we reached the Shumagin Islands. They were abundant only at
the southeastern end of Little Koniuji, where we encountered perhaps
10,000 in Yukon Harbor and more than 50,000 in a small cove directly
south of Yukon Harbor on the opposite side of the island. As numerous as
they were, they did not match Townsend's myriads or even come close to
his assessment that they "were here more numerous than the 'choochkies' at
St. George." St. George Island in the Pribilofs is famous for its least auklets
which, in the past, have been estimated to number as high as 36 million
(Peterson and Fisher 1955). The numbers there today do not even approach
this level and we have no way of knowing how abundant they were when
Townsend visited the Pribilofs, but I think it is safe to say that they
probably numbered in the millions. There are probably more crested auklets
than we observed on Little Koniuji, but there is certainly no longer anything

approaching millions of birds. Properly pronounced, Koniuji is the Aleut
name for the crested auklet, so we can assume that the original inhabitants
were impressed by its numbers.
During the 1973 FWS survey we did not see crested auklets at either
Simeonof or Bird islands. On the overgrazed and cattle-trampled Simeonof
it does not seem possible that any could still exist.
I suspect that a cattleman's greed has been the undoing of any crested
auklets that may have nested on Simeonof Island. This would not account
for the loss of any colonies that may have been on Bird Island, but the
decaying fox-trapper's cabin on that island undoubtedly tells the story.
Churnabura, with its feral cattle, presents much the same problem as
Simeonof. As for Little Koniuji, have horned puffins been partly
responsible for the decrease in crested auklets? The puffin colony at the
south end of Little Koniuji must be exactly where Townsend's millions of
crested auklets once nested.

Least Auklet (Aethia pusilla)

No least auklets were encountered in FWS surveys in the Gulf of Alaska in
the early 1970's. Udvardy (1963) shows their breeding range as starting
well west in the Aleutians. Gabrielson and Lincoln (1959) give the eastern
limit of their breeding range as the Shumagin Islands. Bent (1963) listed
their breeding range as extending east to Kodiak Island, and Friedmann
(1935) knew of only a few specimens taken in the winter from Kodiak.
Perhaps least auklets nested somewhere in the western Gulf of Alaska, and
they may still, but at the moment we have no evidence to prove that they
do.

Rhinoceros Auklet (Cerorhinca monocerata)

Udvardy (1963) would have us believe that the rhinoceros auklet did not
nest between southeastern Alaska and the southern Kurile Islands. Bent
(1963b), on the other hand, lists their breeding range as extending from
Washington to Agattu. Clark (1910) noted this species in small numbers at
Atka and Agattu. Because of the lack of proof, Udvardy probably had no
options. I believe that Bent was probably closer to describing their original

range. I base this assumption on recent observations and on the additional
fragments of information reported by Gabrielson and Lincoln (1959). Murie
(1959) failed to find this species anywhere in the Aleutians, but his primary
reason for being there, the fox-farming industry, may have had a lot to do
with his not being able to find any.
The FWS surveys in Prince William Sound in July-August 1972 located
small numbers of rhinoceros auklets in breeding plumage at the Wooded
Islands and at Stoney Island and Channel Island in Montague Strait. These
birds gave every impression of being local breeders. David Roseneau (Isleib
and Kessel 1973) encountered two at the Barren Islands in June 1965. Isleib
and Kessel (1973) list a few other records from this area.
My own experience leads me to believe that there is a large colony
somewhere on Afognak Island, probably on or near Tonki Cape. On 30 May
1973 I noted a lone bird north of Afognak Island. Later, on 8 and 9 August,
I saw several in the same area. On 13 August in Marmot Strait I observed a
number of rhinoceros auklets, either singly or in groups of up to 12. Some
of these had small fish in their beaks. As they flushed, they all flew off
toward Tonki Cape. This observation was made just at last light, and I
believe that there were many others about that could not be seen in the
dying light. We did not encounter this species along the Alaska Peninsula
during the FWS survey in 1973 until we reached the end. There I had one
quick glimpse of what I was certain was a rhinoceros auklet at Amagat
Island.

Horned Puffin (Fratercula corniculata)

The horned puffin is one of the most abundant breeding birds in the Gulf of
Alaska. There are only a few really large colonies but these birds breed just
about anywhere there is a cliff (even a low one) with suitable fractures and
crevices. During the Alaska Peninsula surveys in 1973, I estimated that the
frequency with which these birds were seen on the water was about half that
of the tufted puffin. They have been recorded in so many places that there is
nothing to be gained by a reiteration of the record in the literature.
The horned puffins reach their greatest density in the Gulf of Alaska west of
Kodiak Island. Murie (1959) estimated that the colony at Amagat Island,
Morzhovi Bay, contained 15,000 birds, one of the largest he had seen. It

contained at least 50,000 in 1973. Even at that, it was no match for the
colony on Little Koniuji Island with its minimum 140,000 horned puffins.
Other colonies with large horned puffin components were at High Island
(40,000), Castle Rock (20,000), Mitrofani Island (35,000), and Sosbee Bay
(15,000).
Earlier in this paper, I commented at length on the great and often rapid
fluctuations in populations of tufted puffins. The same phenomenon affects
horned puffins. In 1975 there were relatively small numbers of horned
puffins at Little Koniuji where they had flourished 2 years earlier (James
Bartonek, personal communication). Because they are apparently subject to
erratically oscillating populations, it is hard to tell how they have fared over
the years.

Tufted Puffin (Lunda cirrhata)

The tufted puffin, as previously indicated, is also a bird with widely
fluctuating populations. Until we develop an understanding of their
population dynamics and can understand the underlying cause of these
fluctuations it will not be possible to assess trends in their populations or
understand the implications of such trends.
Tufted puffins are abundant throughout the Gulf of Alaska. Small colonies
can be located almost anywhere. Along the Alaska Peninsula there are a
number of colonies with an estimated breeding population in 1973 of more
than 15,000 birds. These are: Ashiiak Island (20,000), Central Island
(90,000), the Brother Islands (45,000), The Haystacks (19,000), Castle
Rock (85,000), Bird Island (none, but may contain 500,000-1,000,000 at
times), Peninsula Islands (35,000), the Twins (18,000), Amagat Island
(40,000), and Umga Island (22,000). These colonies correspond to the area
where colonies were listed for the horned puffin.
Tufted puffin populations respond readily to some undetermined short-term
perturbations. This is clearly demonstrated by their rapid population
fluctuations. Because of their numbers and because of the apparent rapidity
with which their numbers rebound, it is not so apparent that they have been
affected by long-term perturbations, as so many other seabirds apparently
have.

There is much unused or underused nesting habitat suitable for this species.
In some cases there are very strong clues pointing to why this habitat is
vacant. On many islands along the Alaska Peninsula, which have very
good-looking tufted puffin nesting habitat and no puffins, there are visible
signs of the presence of fox—either fox trails or abandoned trappers' cabins.
I also suspect that the brown bear (Ursa arctos) is another possible
contributing factor to population declines of burrow nesters along this coast.
I have seen brown bears swimming from island to island on foraging
expeditions. George J. Divoky (personal communication) has found brown
bears visiting Ugaiushak Island, which is 13 km from shore. There are other
islands between Ugaiushak and the mainland but the shortest route from
shore would require one swim of 7 km. The motivation must be strong.
Tufted puffins may shift from colony to colony. This could be an
explanation for apparent local population fluctuation, but if so, I am puzzled
by the apparent tenacity with which puffins cling to some sites. Their
constant occupancy of sites where the vegetative mat is breakaway tundra
(Amundsen 1972) or is underlain by sand results in the destruction of these
sites. Tufted puffins often cling to them in spite of the fact that they have
been reduced to "slums."
My conclusion is that in spite of their large numbers it appears that tufted
puffin populations in the Gulf of Alaska probably have been reduced to a
level below that of their undisturbed state.

Conclusions

Seabird numbers in the Gulf of Alaska are not static. Generally, they are
probably much less abundant than they were when Bering made his voyage
of discovery. There are, nonetheless, considerable numbers of seabirds
breeding along the coasts of these waters. Some species show signs of
recovery from past insults by man. With enlightened management there is
still time to preserve the vast natural heritage that they represent and, in
many cases, to improve their status.
In attempting to address a complicated subject in short space and a
relatively narrow frame of reference, I have certainly erred a number of
times. I would like to see the wealth of new data that will be derived from

current work applied to this concept. An understanding of past population
fluctuations and the underlying perturbations that they reflect is essential
for managers faced with the problem of making good decisions on measures
to mitigate the potential adverse impact of development.

References

American Ornithologists' Union. 1931. Check-list of North
American birds, 4th ed. American Ornithologists' Union,
Baltimore, Md. 530 pp.
American Ornithologists' Union. 1957. Check-list of North
American birds, 5th ed. American Ornithologists' Union,
Baltimore, Md. 691 pp.
Amundsen, C. C. 1972. Plant ecology of Amchitka Island.
Amchitka bio-environmental program. Final Report, Battelle
Columbus Lab., Columbus, Ohio. 27 pp.
Bailey, A. M. 1948. Birds of arctic Alaska. Colo. Mus. Nat. Hist.
Pop. Publ. 8. 316 pp.
Baird, S. F. 1869. On additions to the bird fauna of North
America, made by the scientific corps of the Russo-
American Telegraph Expedition. Trans. Chic. Acad. Sci.
1(2):311-325.
Beaglehole, J. C. 1974. The life of Captain James Cook. Stanford
Univ. Press, Stanford, Calif. 734 pp.
Bean, T. H. 1882. Notes on birds collected during the summer of
1880 in Alaska and Siberia. Proc. U.S. Natl. Mus. 5:144-
173.
Bédard, J. 1976. Coexistence, coevolution and convergent
evolution in seabirds: a comment. Ecology 57(1):177-184.
Belopol'skii, L. O. 1961. Ecology of sea colony birds of the
Barents Sea. (Transl. from Russian.) Israel Program for
Scientific Translations, Jerusalem. 346 pp.

Bendire, C. 1895. Notes on the ancient murrelet
(Synthliboramphus antiquus) by Chase Littlejohn with
annotations. Auk 12(3):270-278.
Bent, A. C. 1963. Life histories of North American diving birds.
Dover Publications, Inc., New York. 239 pp.
Bent, A. C. 1964. Life histories of North American petrels,
pelicans and their allies. Dover Publications, Inc., New
York. 335 pp.
Binford, L. C., B. G. Elliot, and S. W. Singer. 1975. Discovery of
the nest and downy young of the marbled murrelet. Wilson
Bull. 87(3):303-319.
Bowles, J. H. 1908. Tapeworm epidemic among Washington
seabirds. Condor 11:33.
Cahalane, V. H. 1943. Notes on the Kodiak-Afognak Island
group. Auk 60(4):536-541.
Cahalane, V. H. 1944. Birds of the Katmai region, Alaska. Auk
61(3):351-375.
Clark, A. H. 1910. The birds collected and observed during the
cruise of the United States Fisheries Steamer "Albatross" in
the North Pacific Ocean and in the Bering, Okhotsk, Japan
and Eastern seas from April to December 1906. Proc. U.S.
Natl. Mus. 38:25-74.
Cody, M. L. 1973. Coexistence, coevolution and convergent
evolution in seabirds. Ecology 51(1):31-44.
Coues, E. 1874. Birds of the Northwest. U.S. Geological Survey
of the Territories, Misc. Publ. 3. 791 pp.
Dall, W. H. 1873. Notes on the avifauna of the Aleutian Islands,
from Unalaska eastward. Proc. Calif. Acad. Sci. 5(1):25-35.
Dall, W. H. 1874. Notes on the avifauna of the Aleutian Islands,
especially those west of Unalaska. Proc. Calif. Acad. Sci.
5:270-281.

Dall, W. H., and H. M. Bannister. 1869. List of the birds of
Alaska, with biographical notes. Trans. Chic. Acad. Sci.
1(2):267-310.
Dement'ev, G. P., and N. A. Gladkov, eds. 1966. Birds of the
Soviet Vol. I. (Transl. from Russian.) Israel Program for
Scientific Translations, Jerusalem. 553 pp.
Dixon, J. S. 1908. Field notes from Alaska. Condor 10:139-143.
East, B. 1943. Seabird cities of the Aleutians. Nat. Hist. 51:64-71.
Fisher, J., and R. M. Lockley. 1954. Seabirds. William Collins
and Sons, London. 320 pp.
Friedmann, H. 1934. Bird bones from Eskimo ruins on St.
Lawrence Island. J. Wash. Acad. Sci. 24:83-96.
Friedmann, H. 1935. The birds of Kodiak Island, Alaska. Bull.
Chic. Acad. Sci. 5(3):13-54.
Friedmann, H. 1937. Bird bones from archeological sites in
Alaska. J. Wash. Acad. Sci. 27:431-438.
Gabrielson, I. N. 1940. America's greatest bird concentrations,
Part I. Bird Lore 42:497-506.
Gabrielson, I. N. 1941. America's greatest bird concentrations,
Part II. Audubon Mag. 43:15-23.
Gabrielson, I. N. 1944. Some Alaskan notes. Auk 61:105-130,
207-287.
Gabrielson, I. N., and F. C. Lincoln. 1959. The birds of Alaska.
The Stackpole Company, Harrisburg, Penn. 922 pp.
Golder, F. A. 1925. Bering's voyages, Vol. II. American
Geographical Society No. 2. 290 pp.
Grinnell, J. 1910. Birds of the 1908 Alexander Alaskan
Expedition with a note on the avifaunal relationships of the
Prince William Sound district. Univ. Calif. Publ. Zool.
5:361-428.

Hanna, G. D. 1916. Records of birds new to the Pribilof Islands,
including two new to North America. Auk 33:400-403.
Howell, J. C. 1948. Observations on certain birds of the region of
Kodiak Island. Auk 65:352-358.
Hrdlicka, A. 1945. The Aleutian and Commander Islands and
their inhabitants. Wistar Institute Anatomical Biology,
Philadelphia. 630 pp.
Isleib, M. E., and B. Kessel. 1973. Birds of the North Gulf Coast-
Prince William Sound region, Alaska. Biol. Pap. Univ.
Alaska No. 14. 148 pp.
Jaques, F. L. 1930. Water birds observed on the Arctic Ocean and
the Bering Sea in 1928. Auk 47:353-366.
Jochelson, W. 1968. History, ethnology and anthropology of the
Aleut. Carnegie Inst. Wash. Publ. 432. 91 pp.
Johnson, R. A. 1938. Predation of gulls in murre colonies. Wilson
Bull. 50(3):161-176.
Johnson, R. A. 1941. Nesting behavior of the Atlantic murre. Auk
58(2):152-163.
Kozlova, E. V. 1961. Charadriiformes, Suborder Alcae. Fauna of
USSR: Birds 2:1-140. (Transl. from Russian.) Israel
Program for Scientific Translations, Jerusalem. 140 pp.
Lockley, R. M. 1962. Puffins. The Natural History Library,
Anchor Books, Doubleday and Company, Inc., Garden City,
N. Y. 222 pp.
Murie, O. J. 1959. Fauna of the Aleutian Islands and the Alaska
Peninsula. U.S. Fish Wildl. Serv., N. Am. Fauna 61. 406 pp.
Nelson, E. W. 1887. Report upon natural history collections made
in Alaska between the years 1877 and 1881. U.S. Army
Signal Corps. Arct. Ser. Pub. 3.
Nichols, J. T. 1927. Tubinares of the Northwest Coast. Auk
44(3):326-328.

Orth, D. J. 1967. Dictionary of Alaska place names. Geol. Surv.
Prof. Pap. 567. 1084 pp.
Palmer, R. S. 1962. Handbook of North American Birds. Vol. I.
Yale University Press, New Haven, Conn. 567 pp.
Patten, S. M., Jr. 1976. Sympatry and interbreeding of herring
and glaucous-winged gulls in southern Alaska. Pac. Seabird
Group Bull. 3(1):25-26.
Pefaur, J. E. 1974. Egg-neglect in the Wilson's storm petrel.
Wilson Bull. 87(1):16-22.
Peterson, R. T., and J. Fisher. 1955. Wild America. Weather Vane
Books, New York. 434 pp.
Rausch, R. L. 1958. The occurrence and distribution of birds on
Middleton Island, Alaska. Condor 60:227-242.
Schlegel, H. 1862-64. A catalogue of birds in the Dresden
Museum of Natural History, Leyden. Dresden Museum of
Natural History, 7 Vols.
Sowl, L. W., and J. C. Bartonek. 1974. Seabirds—Alaska's most
neglected resource. Trans. N. Am. Wildl. Natl. Resour. Conf.
39:117-125.
Spring, L. 1971. A comparison of functional and morphological
adaptions in the common murre (Uria aalge) and thick-
billed murre (Uria lomvia). Condor 73:1-27.
Stejneger, L. 1885. Results of ornithological explorations in the
Commander Islands and in Kamtschatka. Bull. U.S. Natl.
Mus. 29:1-382.
Stresemann, E. 1949. Birds collected in the North Pacific area
during Captain James Cook's last voyage (1778 and 1779).
Ibis 91:244-255.
Swartz, L. G. 1966. Sea-cliff birds. Pages 611-678 in N. J.
Wilimovsky and J. N. Wolf, eds. Environment of the Cape
Thomson Region, Alaska. U.S. Atomic Energy Commission,
Oak Ridge, Tenn.

Thoresen, A. C. 1964. The breeding behavior of the Cassin's
auklet. Condor 66:456-476.
Townsend, C. H. 1913. The crested auklet. Bird-Lore 15:133-136.
Tuck, L. M. 1960. The Murres. Queen's Printer, Ottawa. 260 pp.
Turner, L. M. 1885. Notes on the birds of the Near Islands,
Alaska. Auk 2:154-159.
Turner, L. M. 1886. Contributions to the natural history of
Alaska. Part V, Birds. U.S. Army, Signal Corps, Washington,
D.C. Pages 115-196.
Udvardy, M. D. F. 1963. Zoogeographic study of the Alcidae.
Pages 85-111 in J. L. Gressitt, ed. Pacific Basin
biogeography, a symposium. Pac. Sci. Congr. Proc. 10.
U.S. Bureau of Sport Fisheries and Wildlife. 1973. Semidi Islands
wilderness report. Semidi Islands, National Wildlife Refuge.
(Unpublished report)
U.S. Department of Commerce. 1964. United States Coast Pilot,
No. 9, Pacific and Arctic Coasts, Cape Spencer to the
Beaufort Sea. Coast and Geodetic Survey, Washington, D.C.
330 pp.
Walker, E. P. 1923. Definite breeding record for the Aleutian tern
in southern Alaska. Condor 25:113-117.
Willet, G. 1914. Birds of Sitka and vicinity, Southeastern Alaska.
Condor 16:71-91.
Willet, G. 1918. Bird notes from Forrester Island, Alaska. Condor
20:85.
Williamson, F. S. L., and L. S. Peyton. 1963. Interbreeding of
glaucous-winged herring gulls in the Cook Inlet Region,
Alaska. Condor 65:28.

Status and Distribution of Breeding Seabirds of Southeastern Alaska, British Columbia, and
Washington

by
David A. Manuwal
College of Forest Resources
University of Washington
Seattle, Washington 98195
and
R. Wayne Campbell
Provincial Museum
Victoria, British Columbia, Canada

Abstract

Current breeding seabird population estimates, nest-site preferences, and population
changes are reviewed for southeastern Alaska, British Columbia, and Washington. There are
19 species of seabirds and a minimum of 216,566 pairs breeding in British Columbia and
Washington. There are limited data on breeding populations for southeastern Alaska.
Species diversity ranges from 17 species in Alaska to 15 species in British Columbia and 14
species in Washington. Eighty percent of all British Columbia seabirds breed on the east
coast of Queen Charlotte Islands and the northwest coast of Vancouver Island. The three
most numerous species in British Columbia are the fork-tailed storm-petrel, Oceanodroma
furcata (31.3%); Cassin's auklet, Ptychoramphus aleuticus (24.6%); and ancient murrelet,
Synthliboramphus antiquus (12.5%). In Washington, 74% (43,274 pairs) of the seabird
population resides on the Olympic coast; the remaining 26% are in the San Juan Island area.
About 54% of this population consists of the common murre (Uria aalge) and rhinoceros
auklet (Cerorhinca monocerata). The rhinoceros auklet and glaucous-winged gull (Larus
glaucescens) make up 97% of the total seabird population of the San Juan Islands. About
68% of all seabirds on the northeastern Pacific coast are nocturnal, burrow or rock crevice-
nesting species. Currently available population data are inadequate to determine significant
changes in population density for most species. Suggested topics for future research are
presented.
The purpose of this paper is to discuss the known distribution, habitat, abundance, and status of breeding seabirds
of the Alexander Archipelago in southeastern Alaska, the Province of British Columbia, Canada, and the State of
Washington.
Even though several studies of the breeding biology of several seabird species in this area have been published,
there have been few published surveys of known breeding colonies. In British Columbia the most extensive work
has been done by the British Columbia Provincial Museum and the University of British Columbia (Drent and
Guiguet 1961). Gabrielson and Lincoln (1959) summarized the available literature on Alaskan birds up to about
1958. Since then, no extensive surveys have been conducted in southeastern Alaska. The U.S. Department of the
Interior (1972), in its environmental impact statement for the Trans-Alaska Pipeline, presented additional
information on the seabirds of other parts of Alaska. In Washington, there are no published comprehensive surveys
except those of Kenyon and Scheffer (1961) and unpublished surveys by the U.S. Fish and Wildlife Service and
the University of Washington.

Table 1. Taxonomic distribution of marine birds breeding along the Pacific Coast of
Washington, British Columbia, and southeastern Alaska.

Regions
British Southeastern Total
Family Common name ColumbiaWashington Alaska forms
Hydrobatidae Storm-petrels 2 2 2 2
Phalacrocoracidae Cormorants 3 3 1 3
Haematopodidae Oystercatchers 1 1 1 1
Laridae Gulls and terns 2 2 3 4
Alcidae Auks, murres, puffins 6 7 9 9
Total 14 15 16 19

Taxonomic Distribution of Marine Birds

There are 19 species of seabirds that breed along the Pacific coast of southeastern Alaska, British Columbia, and
Washington (Table 1). Southeastern Alaska has the largest number (17) of species. Errors in species identification
are most likely with the Larus gulls, particularly in southeastern Alaska where the herring gull (L. argentatus) and
glaucous-winged gull (L. glaucescens) breed in mixed colonies (Patten and Weisbrod 1974). A similar situation
exists in Washington where the western (L. occidentalis) and glaucous-winged gulls intergrade (Scott 1971).
Brandt's (Phalacrocorax penicillatus) and double-crested cormorants (P. auritus) are often difficult to identify
from the air. This would be a problem in Washington and the southwest coast of Vancouver Island, where the two
species are locally sympatric.

Southeastern Alaska

The area under consideration is the 400-km-long Alexander Archipelago (Fig. 1). This complex pattern of islands,
bays, and inlets is characterized by extremely high precipitation and typical cool marine temperatures. Average
annual precipitation in the Sitka area is 245.4 cm (1931-60), and the average annual temperature is 6.3°C (U.S.
Weather Bureau 1974). As a consequence of this cool, humid environment, most of the islands are densely covered
with conifers, chiefly Sitka spruce (Picea sitkensis) and hemlock (Tsuga heterophylla), and an almost impenetrable
shrub cover composed of salmonberry (Rubus spectabilis), elderberry (Sambucus callicaipa), devil's club
(Echinopanax horridus), and three species of Vaccinium (Heath 1915).

Fig. 1. Map of southeastern Alaska showing major seabird breeding colonies: 1
—North Marble Island; 2—Forrester Island.

There are 16 species of marine birds breeding in the Alexander Archipelago. The major seabird breeding colonies
are located at Glacier Bay and at St. Lazaria, Hazy, and Forrester islands (Fig. 1; Table 2). Published surveys of
these colonies are available only for St. Lazaria (Willett 1912) and Forrester islands (Heath 1915; Willett 1915).
Several authors have reported on seabirds from surrounding areas (Grinnell 1897, 1898, 1909; Swarth 1911, 1922,
1936; Patten 1974). There have been no surveys of seabirds of southeastern Alaska since before the 1940's (J. G.
King, Jr., personal communication). However, since census data are available for only two colonies, we discuss
them in more detail.

Table 2. Population estimates of seabirds breeding on St.
Lazaria and Forrester islands, southeastern Alaska
(data from Willett 1912 and 1915).
St. Lazaria Forreste
Island r Island
Numbe
r of Percent Number Percent
Bird species pairs of total of pairs of total
Fork-tailed storm-petrel 2,000 8.0 10,000 6.0
Leach's storm-petrel 20,000 80.0 50,000 30.0
Pelagic cormorant 150 0.6 150 0.0
Black oystercatcher 4 0.0 50 0.0
Glaucous-winged gull 300 1.2 8,000 4.8
Herring gull 220 0.0
Common murre 300 1.2 20,000 12.0
Pigeon guillemot 150 0.6 300 0.0
Ancient murrelet 20,000 12.0
Cassin's auklet 2,000 1.2
Rhinoceros auklet 75 0.0 20,000 12.0

Horned puffin 12 0.0 1,100 0.7
Tufted puffin 2,000 8.0 35,000 21.0
Total 24,991 166,820
The studies by Willett (1912, 1915) and Heath (1915) provide some base-line information on species composition
and abundance with which future studies on St. Lazaria and Forrester islands can be compared (Table 2). The
somewhat greater species diversity on Forrester Island is primarily due to its greater size and more suitable soil
type for ancient murrelets (Synthliboramphus antiquus) and Cassin's auklets (Ptychoramphus aleutica), species
that are absent on St. Lazaria. Storm-petrels (Oceanodroma spp.) are the most numerous species on both islands,
but there are proportionately more storm-petrels (88%) on St. Lazaria than on Forrester (36%). On the other hand,
there are many large, burrowing alcids on Forrester Island. Nearly a third of the birds on Forrester are rhinoceros
auklets (Cerorhinca monocerata), tufted puffins (Lunda cirrhata), and horned puffins (Fratercula corniculata).
The species composition of seabirds breeding on other islands is similar to that found on Forrester and St. Lazaria
islands but less abundant. In Glacier Bay, for example, the only population data available are those provided by
Patten (1974) for North Marble Island: pelagic cormorants, Phalacrocorax pelagicus (30 pairs); black
oystercatchers, Haematopus bachmani (8); herring gulls (7); glaucous-winged gulls (500); common murres, Uria
aalge (18); pigeon guillemots, Cepphus columba (60); horned puffins (4); and tufted puffins (30).
At the present time, it is impossible to draw any conclusions about changes in population density and distribution
for most of the seabirds breeding in southeastern Alaska. Adequate data are available only for St. Lazaria and
Forrester islands where Willet and Heath provided the only early extensive census data for this part of Alaska.

British Columbia

The rugged British Columbia coastline is characterized by 930 km of islands and inlets (Figs. 2, 3). With the
exception of the inner southern portion, this coast is mostly uninhabited. The physical characteristics of the
offshore islands are similar to those found off the Washington coast. Descriptions of some of these islands and the
15 species of breeding seabirds on them have been given by Drent and Guiguet (1961), Guiguet (1971), and
Summers (1974).
A detailed analysis of British Columbia seabirds is not presented here since a more thorough analysis is in
preparation by R. W. Campbell and R. H. Drent (manuscript). Instead, we present seabird population estimates
available for the Province up to the summer of 1975; Tables 3 and 4 summarize these estimates for the five major
portions of coastal British Columbia. The coast of British Columbia contains a myriad of small islands where there
may be small numbers of breeding seabirds. Many of these have not been censused and are too numerous to
include in Tables 3 and 4.

Fig. 2. Map of northern British Columbia showing sites of major seabird
breeding colonies: 1—Skedans Island; 2—Limestone Island; 3—Agglomerate
Island; 4—Bischoff Island; 5—Ramsey Island; 6—Alder Island; 7—Rankins
Island.

Fig. 3. Map of southern British Columbia showing sites of major seabird
breeding colonies: 1—Triangle Island; 2—Cleland Island.

More than half of the breeding seabirds in British Columbia are found on the east coast of the Queen Charlotte
Islands, and the fork-tailed storm-petrel (Oceanodroma furcata) comprises more than half of that total. However,
new unpublished data (K. Vermeer) for Triangle Island and the northwest coast of Vancouver Island indicate that
the population figures in Table 3 for this area are underestimates. Nevertheless, these two regions have nearly 80%
of all the breeding seabirds in the Province. This results from the very large populations of the rhinoceros auklet
and tufted puffin on Triangle Island and the fork-tailed storm-petrel, ancient murrelet, and Cassin's auklet on
various islands on the east coast of the Queen Charlotte Islands (Table 3).
Continuing surveys of breeding seabirds are being conducted by personnel of the British Columbia Provincial
Museum and the Canadian Wildlife Service.

Washington State

General Environment

For this report, we have distinguished two major geographical areas in Washington where breeding seabirds are
found—the western coast of the Olympic Peninsula and the San Juan Islands, including the Strait of Juan de Fuca.
On the Olympic Peninsula, seabirds breed on the offshore rocks, islands, and precipitous cliffs from Copalis Beach
to Cape Flattery (Fig. 4). The offshore rocks and islands throughout this area (except Tatoosh Island) are now
included in the Washington Islands National Wildlife Refuge. Most of the larger rocks and islands have dense
stands of salmonberry, salal, and grasses, and a few support stands of stunted conifers (Fig. 5); most are
inaccessible to man. The adjacent coast is dominated by the Olympic rain forest where the mean annual
precipitation is about 337.1 cm (U.S. Weather Bureau 1956, 1965a, 1965b).
Because the San Juan Islands lie northeast of the Olympic Peninsula and east of Vancouver Island (Fig. 6) they are
in a rain shadow; however, because of highly variable topography and aspect, most islands have a diverse
assemblage of plant communities (Franklin and Dyrness 1973). Exposed south-facing slopes are occupied by
grassland vegetation and frequently by scattered trees, usually Pseudotsuga menziesii and Arbutus menziesii. Most
of the seabird colonies are located on rather small exposed islands with short, grassy, shrubby vegetation. In
general, these islands are not suitable for burrowing species.

Table 3. Species composition, population estimates, and distribution of seabirds in British Columbia.[5]
[6]
(+ = Present.)
Straits
of West East Prince
Georgia Southwest Northwest coast of coast of Rupert
and coast of coast of Queen Queen to Queen
Juan de Vancouve Vancouve Charlotte Charlotte Charlotte Total Percent
Bird species Fuca r Island r Island Island Island Island birds of total
Fork-tailed storm-petrel + + 1,050 97,100 + 98,160 31.3
Leach's storm-petrel 10,000 + 1,800 180 750 12,730 4.1
Double-crested cormorant 1,058 0 0 0 0 0 2,116 >1.0
Brandt's cormorant 370 0 0 0 0 370 >1.0
Pelagic cormorant 2,174 336 3,350 1,456 496 12 9,998 3.2
Glaucous-winged gull 10,123 6,870 600 412 866 540 29,534 9.4
Common murre 16 3,000 0 0 0 3,016 1.0
Pigeon guillemot 1,029 204 250 358 1,458 1,650 5,978 1.9
Ancient murrelet 0 0 200 42,150 4 42,354 13.5
Cassin's auklet + 50,000 + 26,500 450 76,950 4.6
Rhinoceros auklet 1,200 + 10,000 300 200 11,700 3.7
Tufted puffin 1 154 20,000 190 0 42 20,388 6.5
Total 14,385 19,150 77,200 15,466 169,050 3,648313,294 81.2

Table 4. Breeding seabird population estimates for British Columbia[7][8]

Geographic location Population estimate Percent of total
Straits of Georgia and Juan de Fuca 14,385 9.2
Southwest Coast of Vancouver Island 9,575 6.1
Northwest Coast of Vancouver Island 38,600 24.6
West Coast of Queen Charlotte Island 7,733 4.9
East Coast of Queen Charlotte Island 84,530 54.0
Prince Rupert to Queen Charlotte Strait 1,824 1.2
Total 156,647 100.0

Fig. 4. Map of the Olympic Peninsula of Washington
State showing sites of major seabird breeding
colonies: 1—Protection Island; 2—Carroll Island; 3
—Destruction Island.

In the Strait of Juan de Fuca, the two most important sites are Smith and Protection islands. Both are composed of
glacial deposits and heavy sod that has developed under dense grassy vegetation (Fig. 7). Consequently, these two
islands support most of the burrowing seabirds in the region. Unfortunately, both islands have historically been
subjected to much human disturbance (Richardson 1961; Manuwal 1974).
The existing information on seabird colonies in both the coastal and San Juan Island areas has been largely derived
from aerial surveys by the U.S. Fish and Wildlife Service. These surveys are inherently biased toward surface-
nesting species such as gulls and cormorants. Population estimates for guillemots, auklets, storm-petrels, and
puffins are less accurate. Some additional information obtained by direct island visitation has been provided by
Kenyon and Scheffer (1961), Richardson (1961), Thoresen and Galusha (1971), G. Eddy (unpublished data), and

D. A. Manuwal (unpublished data). Although other accounts of Washington seabirds are available, the references
listed above are specifically oriented toward population assessment.

Olympic Peninsula

Despite the large number of offshore rocks, islets, and islands along the Pacific coast of Washington, significant
seabird colonies are present only on about 30 islands. Since Table 5 summarizes the population estimates for 12
species of seabirds breeding on 24 major sites, it represents only the majority and not the total number of breeding
seabirds on the Pacific coast of Washington. About 74% of the entire Washington seabird population resides on the
coastal rocks and islands.
Major colony sites with more than 2,500 breeding pairs are Grenville Arch, Willoughby Rock, Destruction Island,
Cake Rock, Carroll Island, and Bodelteh Island. More intensive censusing, especially of nocturnal burrowing
species will undoubtedly raise the population estimates for these and other islands off the coast. About 54% of the
total coastal population is composed of the common murre and rhinoceros auklet.

Fig. 5. Photograph of Destruction Island off the coast of Washington.

Fig. 6. Map of the San Juan Archipelago showing sites of major seabird
breeding colonies: 1—Viti Rocks; 2—Colville Island; 3—Smith Island.

San Juan Islands

There are about 86 actual or potential seabird colony sites in this area; 25 (30%) are now considered important.
Eleven islands are under Federal protection as National Wildlife Refuges. Part of Protection Island is owned by the
Washington State Game Department to protect the largest rhinoceros auklet colony in the State. Most colony sites
are on small islands with poorly developed soil which prevents burrowing species from using them. Consequently,
the dominant species are surface nesters (such as gulls and cormorants) and rock-crevice nesters (like the pigeon
guillemot). In all, about 31,000 seabirds of 7 species breed in the San Juan Island area. Breeding seabird
population estimates for 49 of the 86 nesting sites are given in Table 6. Even though this does not represent all the
colonies, it covers the most important islands and those islands where there appears to be potential for seabird
breeding.

Fig. 7. Photograph of Smith Island in the Strait of Juan
de Fuca, Washington. The glacial deposits are evident
from the composition of the cliff faces.

Table 5. Estimated breeding seabird populations of the outer coast of Washington.[9] (Unpublished data from
U.S. Fish and Wildlife Service and University of Washington)
Species
Storm-pet­‐
rels Cor­mo­rants Gulls Auk­lets
Glau­‐
Black cous- Pi­‐
Dou­‐ oys­‐ wing­‐ geon Tuft­‐
Un­i­‐ ble- ter- ed Com­‐ guil­‐ Rhi­‐ ed
Breed­ing Fork- Le­‐ den­‐ crest­‐ Bran­‐ Pe­‐ catch­‐ West­‐ west­‐ mon le­‐ Cass­‐ noc­er­‐ puf­‐
site tail­ed ach's ti­fied ed dt's lag­ic er ern ern mur­re mot in's os fin To­tal
Copalis
— — 15 — — — — 30 — — — — — — 45
Rock
Point
— — — 60 30 80 — 165 40 1,100 — — — — 1,475
Grenville
Grenville
— — — 30 20 — 1 60 — 3,000 4 — — 3 3,118
Arch
Flat Rock — — 30 — — — — — 60 300 — — — — 390
Split Rock — — — 100 — — 1 150 — 2,100 4 — — — 2,355

Willoughby
— — — 80 40 15 — 150 — 3,000 — — — 25 3,310
Rock
South Rock — — — — — 40 — — 50 — — — — — 90
Abbey Islet — — — — — 30 3 — 50 — — — — 10 93
Destruction
— — — — — — 12 350 — — 25 — 10,940 350 11,677
Island
Middle
— — — — — 25 — — 25 — 50 — — — 100
Rock
North Rock — — — — — — — — 25 — — — — — 25
Alexander
— — — — — 50 5 — 225 — — — — 1,550 1,830
Island
Rounded
— — — — — 25 — 25 — — 1 — — — 51
Island
Giant's
— — — — — 10 — — — 150 — 50 150 — 360
Graveyard
Quillayute
— — — 50 50 50 — — 150 900 — — — 350 1,550
Needles
James
— 30 — — — 40 — — 150 750 40 — — 20 1,030
Island
Cake Rock — 500 — — — 150 — — 600 300 12 — 50 1,000 2,612
Sealion
— — — 70 — 30 — — 250 — — — — 5 355
Rock
Carroll
— 3,100 — — — 100 3 — 550 — — 25 250 2,400 6,428
Island
Ball Rock — — — — — 50 7 — 150 — — — — 750 957
White
— — — — — 100 — — 75 250 — — — 100 525
Rock
Ozette
— — — — — — 1 — 15 — — — — — 16
Island
Bodelteh
1,900 — — — — 100 2 — 300 — 5 — — 750 3,057
Island
Tatoosh
— 25 — — — 100 — — 1,500+ 100 20 25? 25? 30 1,825
Island
Total 1,900 3,655 45 390 140 995 35 930 4,215 11,950 161 100 11,415 7,343 43,274

Table 6. Breeding seabird population estimates for the San Juan Islands and Strait of
Juan de Fuca, Washington, 1973-75.[10]
Species
Cor­mo­rants Black Glau­‐ Rhi­‐
Dou­‐ oys­ter- cous- Pi­geon noc­er­‐
ble- Pe­lag­‐ catch­‐ wing­‐ guil­le­‐ Tuft­ed os
Breeding site crest­ed ic er ed gull mot puf­fin Auk­let To­tal
Bare Island — 50 1 120 + — 2 173
Barren Island — — — — — — — 0
Battleship Island — — — — — — — 0
Bird Rocks 30 — + 320 — — — 350
Cactus Island — — 1 — — — — 1
Castle Island — — — — 30 — — 30
Colville Island — 40 1 1,000 — — — 1,041
Danger Island — — — 125 7 — — 132
Decatur Island — — — — — — — 0
Eliza Island — — — 3 1 — — 4

Eliza Rock — — — 1 — — — 1
Flat Top Island — — — — + — — +
Flower Island — 17 — 90 — — — 107
Goose Island — — — 60 — — — 60
Gull Rock — — + 125 7 — — 132
Gull Reef — — — — — — — 0
Hall Island — — 1 275 — — — 276
Harbor Rock — — — — — — — 0
Iceberg Island — — — — — — — 0
Johns Island — — 1 — — — — 1
Long Island — — 8 80 — — — 88
Low Island — — 1 75 17 — — 93
Lummi Rocks — — — 4 — — — 4
Matia Island — — — — + — — +
Mummy Rocks — — — 55 — — — 55
Minor Island — — — 100 — — — 100
O'Neal Island — — — — — — — 0
Patos Island — — — 20 + — — 20
North Peapod Island — — 1 220 2 — — 223
South Peapod Island — — 1 75 2 — — 78
Pearl Island — — — — — — — 0
Pointer Island — — — 58 2 — — 60
Protection Island 3 110 3 1,500 30 9,200 35 10,881
Puffin Island — — 1 350 15 — — 366
Ripple Island — — — — — — — 0
Sentinel Island — — — — 10 — — 10
Sentinel Rock — — 1 — — — — 1
Skip Jack Island — — — 75 20 — — 95
Smith Island — 20 6 10 30 600 — 666
Speiden Island — — — — — — — 0
South Sister Island 2 11 1 131 — — — 145
Middle Sister Island — — 1 22 — — — 23
North Sister Island — — 2 412 3 — — 417
Viti Rocks 29 80 1 387 1 — — 498
Waldron Island — — — — 2 — — 2
Williamson Rocks — 67 1 346 2 — — 416
Whale Island — — 1 70 — — — 71
White Rock — — + 125 13 — — 138
Yellow Island — — — — — — — 0
Total per species 64 395 34 6,234 194 9,800 37 16,758
Percent of total population 0.4 2.3 0.2 37.2 1.2 58.5 0.2 100.0
The major colony sites with more than 250 breeding pairs are located at Protection and Smith islands, Bird Rocks,
Colville Island, Hall Island, North and South Peapod rocks, Puffin Island, North Sisters, Viti Rocks, and
Williamson Rocks (Fig. 6). Glaucous-winged gulls are the predominant species on all these islands except
Protection and Smith islands, where there are large colonies of rhinoceros auklets. Rhinoceros auklets (65%) and
glaucous-winged gulls (32%) make up 97% of the total San Juan Islands seabird population.

Nest-site Preferences

Food supply and availability of nest sites are two critically important factors influencing the distribution and
abundance of seabirds. Whereas information on general diet composition is known for most seabird species, we

know little about the availability of favored seabird prey. The dynamics of seabird food chains is reviewed
elsewhere in these proceedings.
The nest-site preferences for seabirds of the northeast Pacific Ocean are given in Table 7, and Table 8 indicates the
proportion of seabirds that belong to specific nest-site categories. These preferences, in conjunction with
knowledge of the physical characteristics of seabird habitat, permit a partial explanation of the present distribution
and abundance of seabirds. For example, if we compare the San Juan Island habitats with those of the Washington
coast, it is apparent that there are more cliff-nesting species on the coast. This reflects the physical characteristics
of the two habitats. There are few cliffs in the San Juan Islands, and those that exist are very unstable. Colony sites
in the San Juan Islands are typically on low, flat islands. Glaucous-winged gulls are the most abundant nesting
species there. Coastal islands, on the other hand, are either covered by dense vegetation or are large monolithic
chunks of rock with few available flat areas. Population estimates for the Washington coast are heavily biased
toward surface nesters, since most of the data have been gathered by aerial surveys. Consequently, the burrow and
rock crevice categories are underestimated. The aerial survey is appropriate for only about 43% of the birds nesting
on the Washington coast.

Table 7. Nest-site preference for seabirds
breeding from Cape Fairweather, Alaska,
to the Columbia River, Washington.
Nest-site type Bird species
Burrow-rock crevice
Diurnal Pigeon guillemot
Horned puffin
Tufted puffin
Nocturnal Fork-tailed storm-petrel
Leach's storm-petrel
Kittlitz's murrelet
Ancient murrelet
Cassin's auklet
Rhinoceros auklet
Open nests
Flat or slope Double-crested cormorant
Brandt's cormorant
Glaucous-winged gull
Herring gull
Western gull
Black oystercatcher
Cliff face Pelagic cormorant
Common murre
Black-legged kittiwake
Tree branch Marbled murrelet

Northern and southern British Columbia provide another good example of habitat availability as revealed through
seabird population estimates. The population data are more comprehensive and have largely been gathered by
island visitations. The islands in the northern portion are heavily vegetated and many have well-developed soil into
which storm-petrels, auklets, and murrelets can burrow. Indeed, 96% of the seabird population consists of
nocturnal, burrow-nesting species. In southern British Columbia, however, there are more open-nest species,
particularly glaucous-winged gulls and cormorants.
Overall, 68% of the breeding seabirds found along the northeastern Pacific coast are nocturnal and nest in burrows
or rock crevices (Table 8). The most conspicuous nesting birds such as gulls, cormorants, and murres, comprise
only 22% of the total population. Consequently, our current estimates of breeding seabirds still underestimate the
more secretive, nocturnal, burrow-nesting species.

Table 8. Proportional nest-site preferences of Pacific coast seabirds.[11]

Estimated number of pairs Percent of population
British Columbia San British Columbia San Total
Juan Washington Juan Washington
Site Northern Southern Islands coast Northern Southern Islands coast PopulationPercent
Burrow-
rock crevice
Diurnal 1,849 11,334 231 7,504 2.0 18.1 1.4 17.3 20,918 9.7
Nocturnal 90,347 30,600 9,800 17,070 96.0 48.9 58.6 39.4 147,817 68.1
Open nests
Flat or
909 15,101 6,298 5,755 1.0 24.2 37.6 13.3 28,063 13.0
slope
Cliff face 982 5,525 395 12,945 1.0 8.8 2.4 30.0 19,847 9.2
Total 94,087 62,560 16,724 43,274 216,645

Population Changes

The available data are inadequate to detect changes in population distribution and density for most species (Table
9). In Washington, for instance, limited unsubstantiated information suggests an overall decline of the double-
crested cormorant and tufted puffin in the San Juan Island area. Likewise, there seems to be an increase in
glaucous-winged gulls there. In British Columbia, Drent and Guiguet (1961) were able to detect changes in some
species. For example, they noted increases in the double-crested cormorant, pelagic cormorant, and glaucous-
winged gull. No change was observed in the tufted puffin. Since then, the Brandt's cormorant has established a
colony in Barkley Sound (Guiguet 1971). The data in southeastern Alaska are inadequate for all species except,
perhaps, the Cassin's auklet which Gabrielson and Lincoln (1959) reported to be declining throughout Alaska. In
short, no definitive statements can now be made concerning changes in seabird population numbers.

Species Accounts

Fork-tailed Storm-petrel (Oceanodroma furcata)

Storm-petrels are especially difficult to census because they are nocturnal, and the burrows and rock crevices
where they breed are often difficult to locate, especially in mixed-species colonies. The census data are inadequate
to determine whether there have been changes in population density and distribution. Indeed, the biology of this
species is perhaps the least known of the North Pacific colonial seabirds. In southeastern Alaska, this species is
outnumbered by at least 5 to 1 by the Leach's storm-petrel (Oceanodroma leucorhoa). The reasons for this are
poorly understood. There is some evidence that the numbers of breeding fork-tailed storm-petrels on Forrester
Island may fluctuate drastically from one year to the next (Gabrielson and Lincoln 1959).

Leach's Storm-petrel (Oceanodroma leucorhoa)

Of the two subspecies of this petrel (O. l. leucorhoa and O. l. beali), only O. l. beali is found in southeastern
Alaska. The leucorhoa subspecies is more northerly in distribution. Where both fork-tailed and Leach's storm-
petrels are sympatric, Leach's predominates; however, this relationship becomes more unpredictable in British
Columbia and Washington. This species is undoubtedly widespread in the forested islands of the Alexander
Archipelago.

Double-crested Cormorant (Phalacrocorax auritus)

The double-crested cormorant apparently does not breed in southeastern Alaska since Willett (1912), Gabrielson
and Lincoln (1959), and S. Patten (personal communication) do not report breeding colonies for the area. The
largest populations occur in southern British Columbia principally in the Gulf Islands, where 71% of all breeding
double-crested cormorants are found (Table 10). According to Jewett et al. (1953), this species was less common in
Puget Sound than was Brandt's cormorant, but is certainly not the case today (D. A. Manuwal, unpublished data).
The only common cormorants in the San Juan Islands are the pelagic and double-crested species. The double-

crested cormorant seems to have declined in numbers on both coastal and inland waters. On the basis of his
observations, R. W. Campbell believes that this species is increasing in British Columbia.

Table 9. Distribution and status of marine birds breeding along the Pacific coast of Washington, British
Columbia, and southeastern Alaska. (X = known to breed in the region;? = data insufficient; + =
evidence indicates an overall increase in size of population; - = evidence indicates an overall decrease in
size of population; 0 = no population change.)
British Southeastern
Washington Columbia Alaska
Family and species Common name Presence Status Presence Status Presence Status
Hydrobatidae
Oceanodroma furcata Fork-tailed storm-
X ? X ? X ?
petrel
O. leucorhoa Leach's storm-petrel X ? X - X ?
Phalacrocoracidae
Phalacrocorax auritus Double-crested
X - X -
cormorant
P. penicillatus Brandt's cormorant X ? X 0 ?
P. pelagicus Pelagic cormorant X ? X + X ?
Haematopodidae
Haematopus bachmani Black oystercatcher X ? X + X ?
Laridae
Larus glaucescens Glaucous-winged gull X + X + X ?
L. occidentalis Western gull X ? X ?
L. argentatus Herring gull X ?
Rissa tridactyla Black-legged
X ?
kittiwake
Alcidae
Uria aalge Common murre X ? X - X ?
Cepphus columba Pigeon guillemot X ? X + X ?
Brachyramphus
Marbled murrelet X ? X ? X ?
marmoratus
B. brevirostris Kittlitz's murrelet X ?
Synthliboramphus
Ancient murrelet X ? X ?
antiquus
Ptychoramphus aleuticus Cassin's auklet X ? X ? X -
Cerorhinca monocerata Rhinoceros auklet X ? X + X ?
Fratercula corniculata Horned puffin X ?
Lunda cirrhata Tufted puffin X - X 0 X ?
Total species 14 15 16

Brandt's Cormorant (Phalacrocorax penicillatus)

Brandt's cormorant is the least abundant of the three cormorant species that nest in the study area. Washington is at
the northernmost edge of the breeding distribution of this species. Only one more northerly colony exists, on
Sartine Island off Vancouver Island (Vermeer et al. 1976). Brandt's cormorant comprises about 85% of the
cormorant population in Oregon (U.S. Fish and Wildlife Service, unpublished data). However, in Washington it is
only about 9% and in British Columbia 3% of the total cormorant population.

Table 10. Estimated seabird populations breeding from Cape Fairweather, Alaska, to the Columbia
River, Washington.[12][13][14] (? = present in unknown numbers; - = inadequate data.)
Bird species Northern Southern San Juan Washington Total
British British Islands coast all

Columbia Columbia regions
Pop­u­‐ Per­‐ Pop­u­‐ Per­‐ Pop­u­‐ Per­‐ Pop­u­‐ Per­‐ Pop­u­‐ Per­‐
la­tion cent la­tion cent la­tion cent la­tion cent la­tion cent
Fork-tailed storm-petrel 49,080 52.2 ? - 0 - 1,900 4.4 50,980 23.5
Leach's storm-petrel 1,365 1.5 5,000 8.0 0 - 3,655 8.5 10,020 4.6
Double-crested cormorant 0 - 1,058 1.7 64 >0.1 390 >0.1 1,512 >0.1
Brandt's cormorant 0 - 185 >0.1 0 - 140 >0.1 325 >0.1
Pelagic cormorant 982 1.0 4,017 6.4 395 2.4 995 2.3 6,389 3.0
Glaucous-winged gull 909 1.0 13,858 22.2 6,234 37.3 4,215 9.8 25,216 11.6
Western gull 0 - ? - 0 - 930 2.2 930 >0.1
Common murre 0 - 1,508 2.4 0 - 11,950 27.7 13,458 6.2
Pigeon guillemot 1,733 1.8 1,256 2.0 194 1.2 161 >0.1 3,345 1.5
Ancient murrelet 21,177 22.5 0 - 0 - 0 - 21,177 9.8
Cassin's auklet 13,475 14.3 25,000 40.0 0 - 100 >0.1 38,575 17.8
Rhinoceros auklet 5,250 5.6 6,000 >0.1 9,800 58.6 11,415 26.4 27,065 12.5
Horned puffin 0 - 0 - 0 - 0 - 0 -
Tufted puffin 116 >0.1 10,078 16.1 37 >0.1 7,343 17.0 17,574 8.1
Total 94,087 67,960 16,724 43,194 216,566
Comparing information in Jewett et al. (1953) with the current situation, it is apparent that there has been a drastic
change in the distribution and probably in the numbers of this species in Washington. Today, there are no Brandt's
cormorant colonies in the San Juan Islands or Strait of Juan de Fuca. Yet Jewett et al. (1953) reported colonies at
Bellingham Bay and on Lopez and Matia islands. We have observed juvenile Brandt's cormorants in the San Juan
Islands during the summer. This species may be particularly susceptible to human disturbance, since all three areas
listed above are heavily used in the summer for recreation.

Pelagic Cormorant (Phalacrocorax pelagicus)

The distribution of breeding colonies of the pelagic cormorant is strongly determined by the availability of the
steep cliffs on which it constructs its nest. This is the only common cormorant in southeastern Alaska. Throughout
its extensive range, this species is generally found breeding in small numbers. Nothing is known about fluctuations
in its numbers in Alaska.
This species is common in both British Columbia and Washington; nesting sites are of the same type as those in
Alaska except in the San Juan Islands, where 200-300 birds nest on cliff faces composed of glacial deposits. Here,
there is frequent nest loss due to slippage off the cliff face; this loss is especially severe on Smith and Protection
islands. There do not appear to be any changes in the distribution of pelagic cormorants, but an accurate
assessment of abundance is impossible from the data currently available.

Glaucous-winged Gull (Larus glaucescens)

The glaucous-winged gull is the characteristic gull of southeastern Alaska and British Columbia. In Washington, it
is the dominant gull in the San Juan Island area but interbreeds with the western gull on the Washington outer coast
from Tatoosh to Copalis Beach (Scott 1971). In Alaska, it is widely distributed and locally abundant on Forrester
Island, St. Lazaria, and throughout Glacier Bay (S. Patten, personal communication). The biology of this species
has been extensively studied in the southern part of its range, especially by Vermeer (1963) and James-Veitch and
Booth (1954). The only study of the breeding biology of this species in southeastern Alaska is by Patten (1974) for
Glacier Bay. Glaucous-winged gulls are apparently increasing in British Columbia (R. W. Campbell, unpublished
data) and in Washington (T. R. Wahl, personal communication). This increase is undoubtedly a result of the
proximity of breeding colonies to garbage dumps and commercial fishing fleets in both Canada and the United
States. Little is known about changes in populations of gulls in southeastern Alaska.

Western Gull (Larus occidentalis)

The western gull is the common breeding gull of the Washington outer coast; however, there is increased
interbreeding with glaucous-winged gulls northward from Destruction Island to Tatoosh Island. The percentage of
glaucous-winged gulls steadily increases until Vancouver Island and the Strait of Juan de Fuca, where western
gulls are rare. Population estimates of gulls on the outer coast of Washington are derived primarily from aerial
flights. This makes identification of gulls difficult, and in view of the amount of interbreeding, it is probably
impossible to classify many of the breeding gulls as to species. Western gulls appear to be increasing in the Grays
Harbor area (G. D. Alcorn, personal communication).

Herring Gull (Larus argentatus)

The herring gull is typically found in inland Alaska but can be found uncommonly along the coast of southeastern
Alaska, where it often forms mixed colonies with glaucous-winged gulls. These two species apparently hybridize
where they are sympatric (Williamson and Peyton 1963; Patten and Weisbrod 1974; Patten 1974).

Black-legged Kittiwake (Rissa tridactyla)

The black-legged kittiwake is found only in the northern portions of southeastern Alaska. It apparently is a
common breeding bird in Glacier Bay National Monument (S. M. Patten, Jr., personal communication). No
population estimates are available for this species other than that it is locally abundant.

Common Murre (Uria aalge)

Common murres are common in southeastern Alaska and the coast of Washington but breed only in small numbers
in British Columbia and are absent in the San Juan Islands. Since this species usually prefers cliffs or the tops of
inaccessible rocks, they are probably limited by island topography in British Columbia, and are most certainly so
limited in the San Juan and Gulf Island groups.
In Alaska, common murres breed in unknown numbers in Glacier Bay and in large numbers on St. Lazaria,
Forrester, and the Hazy islands. No data on population changes are available for any of the three regions.

Pigeon Guillemot (Cepphus columba)

The pigeon guillemot is common throughout the region from Cape Fairweather to Washington. Even though it is
not truly colonial, it may be locally abundant where there are suitable nest sites. Since these nest sites are usually
difficult to find, population estimates are seldom accurate, usually being conservative. It is evident that guillemots
appear to be small in number when compared with other seabirds nesting at major colony sites in the north Pacific
region (Table 10). This disparity may be exaggerated by the difficulty of censusing guillemots.

Marbled Murrelet (Brachyramphus marmoratus)

Since the marbled murrelet has been found to nest in coniferous forests (Binford et al. 1975), traditional census
techniques are unsuitable. This species is common in southeastern Alaska (Gabrielson and Lincoln 1959), in
British Columbia (Drent and Guiguet 1961), and in Washington (Jewett et al. 1953).

Kittlitz's Murrelet (Brachyramphus brevirostris)

The difficulties in assessing breeding populations of Kittlitz's murrelet are the same as those for the marbled
murrelet. This species nests on the ground at high elevation near the coast (Bailey 1973). The largest
concentrations are in the vicinity of Glacier Bay National Monument (Gabrielson and Lincoln 1959). They are not
found breeding in Washington or British Columbia.

Ancient Murrelet (Synthliboramphus antiquus)

Ancient murrelets appear to be locally common throughout southeastern Alaska. Their presence is probably
strongly dependent upon a suitable soil in which to excavate burrows. The only available population estimates are
those by Willett (1915) for Forrester Island (Table 1). Censusing this species is especially difficult because its

burrows are easily confused with those of Cassin's auklet. There are no studies of this species in southeastern
Alaska; however, it has been well studied in the Queen Charlotte Islands to the south by Sealy (1975).

Cassin's Auklet (Ptychoramphus aleuticus)

A synthesis of literature and unpublished observations led Gabrielson and Lincoln (1959) to conclude that Cassin's
auklet has greatly decreased in numbers and is not abundant anywhere in Alaska. They also concluded that the
colony on Forrester Island (Table 1) was the only well-documented colony in southeastern Alaska. Fishermen in
the southeastern Alaska area occasionally see this species (M. E. Isleib, personal communication), but it is
apparently still uncommon though more widespread than just Forrester Island. The nocturnal habits and burrowing
in dense vegetation makes censusing this species very difficult. Nothing is known about the ecology of this species
in Alaska.

Rhinoceros Auklet (Cerorhinca monocerata)

Rhinoceros auklets seem to be found breeding only on islands where there is a well-developed soil in which to
excavate their extensive burrows. From the limited evidence available, it appears that the largest rhinoceros auklet
populations probably are to be found in southeastern Alaska. Willett (1912) found a very large population on
Forrester Island (Table 2), and the species has been found in the summer in the Barren Islands east of Kodiak
Island (E. P. Bailey, personal communication). More intensive surveys of the Alexander Archipelago will probably
reveal other populations of this species.
This species is less common in British Columbia than either Alaska or Washington. A possible reason for this is
lack of suitable nesting areas. In Washington, the two largest colonies are at Protection Island in the Strait of Juan
de Fuca and Destruction Island on the outer coast. Smaller numbers exist on other coastal islands and on Smith
Island in the Strait of Juan de Fuca. The Smith Island colony is an interesting one since it appears that early human
disturbance in the late 19th or early 20th century eliminated the species from the island. In their discussion of
Smith Island, Jewett et al. (1953) made no mention of auklets, only of puffins and guillemots. Couch (1929) did
not record the species in 1925. The colony now numbers about 600 pairs.

Horned Puffin (Fratercula corniculata)

Although the horned puffin is one of the most abundant seabirds in other parts of Alaska, it is much less abundant
in the southeastern portion. In addition to the information discussed by Sealy (1973), it now appears that this
species may breed as far south as Triangle Island, British Columbia (K. Vermeer, personal communication; D. A.
Manuwal, personal observation). Here, as on Forrester Island, it is greatly outnumbered by the tufted puffin. No
data are available on the breeding or status of this species in the study area.

Tufted Puffin (Lunda cirrhata)

The tufted puffin is found breeding on scattered islands throughout the region. The largest known colonies are on
Forrester Island, Alaska, Triangle Island, British Columbia, and Carroll Island, Washington. It is notably absent
from most of the gulf and San Juan Islands. Even though puffins have apparently never been numerous in the San
Juan Islands, their population has noticeably declined during the past 35 years. For example, Jewett et al. (1953)
reported a colony of 50 pairs on Bare Island in 1937, but in 1973 only 2 pairs were counted (D. A. Manuwal,
unpublished data). Likewise, in 1915 there were more than 250 pairs on Smith Island, but by 1916 there were only
75 pairs (Jewett et al. 1953). The decline is attributed to rapid erosion of the glacial-deposit cliffs. There are no
puffins on Smith Island today, and the largest colony in the Puget Sound area is the 35 pairs on Protection Island
(D. A. Manuwal, unpublished data).

Discussion

The total minimum estimate of the breeding seabird populations of British Columbia and Washington is 216,500
pairs (Table 10). No comprehensive estimates are available for breeding seabirds of southeastern Alaska. It is
likely, however, that the number of breeding seabirds in the Alexander Archipelago may be equal to (or exceed) the
populations of both British Columbia and Washington. Data are desperately needed from that area. Of the total

seabird population in the study area (Table 10) 43% reside in northern British Columbia. The Washington State
population represents 28% of the total. Fork-tailed storm-petrels comprise almost 25% of all the breeding seabirds
in the area under consideration. The Cassin's auklet is the next most numerous species (18% of the total).
It is apparent that current data are, for the most part, inadequate for assessing anything but catastrophic changes in
seabird breeding colonies. This inadequacy is due to inadequate censusing because of excessive reliance upon
aerial surveys; in the past, this has often been a result of insufficient funding.
Of the several threats facing seabird populations, none may be as important as oil pollution. A general review of
this subject is presented elsewhere by Vermeer and Vermeer (1975). It is apparent from this review that the most
vulnerable species are those that dive beneath the sea surface, including all the alcids and cormorants breeding
along the coast that are discussed in this paper. This group makes up almost 60% of all the breeding seabirds in
this area. Unfortunately, our knowledge of several of these species is scanty and our current census techniques are
unsuitable for most of these birds.
Studies of the changes in seabird numbers have been made in other oceans. For example, in Great Britain (Bourne
1972a, 1972b; Harris 1970), eastern Canada (Nettleship 1973), and the Atlantic coast of the United States (Kadlec
and Drury 1968), two major trends seem apparent. First, there is an overall decline in alcid and tern numbers. The
decline in auks may be due to their extreme vulnerability to oil pollution (Bourne 1972a, 1972b; Vermeer and
Vermeer 1975). The Atlantic puffin, however, may be suffering the additional effects of gull cleptoparasitism
(Nettleship 1972). Secondly, there seems to be an increase in gull populations on both sides of the Atlantic,
particularly the herring gull and black-legged kittiwake.
Compared with the Atlantic coast of North America and northern Europe, the data base for seabird populations of
the Pacific coast is poor. The fragmentary evidence now available indicates that there may be small population
increases in the western and glaucous-winged gulls and range extensions of the Brandt's and double-crested
cormorants and of the rhinoceros auklet (Scott et al. 1974). Whether these changes represent actual population
increases or displacements remains unclear. The remote locations of most of the large Pacific seabird colonies may
provide unofficial protection from human interference. Intensive surveys are needed to establish base-line
inventories in these areas.
As a consequence of this first comprehensive review of the status of breeding marine birds of the northeast Pacific
coast of North America, we recommend the following future research topics as necessary for the conservation of
this great international resource.
• Seabird colony census techniques should be refined since almost 68% of the seabirds in this
area are nocturnal and nest in burrows. The present reliance on aerial censusing, although
economical, is inadequate to census most breeding seabird populations; more on-site
surveys are needed. For surface-nesting species and diurnal, burrowing species, studies on
species specific activity cycles are needed so that census data can be corrected for birds not
observed at the colony. For nocturnal, burrowing species seasonal burrow occupancy rates
must be determined so that burrow counts can be corrected for inactive burrows.
• Comprehensive surveys should be made every 3-5 years.
• In 1980 a coordinated breeding bird survey of the entire Pacific coasts of Mexico, Canada, and
the United States should be conducted.
• Specific islands where key populations exist should be carefully monitored for subtle changes
in population density or species composition.
• Increased study of the breeding biology of seabirds should be carried out so that base-line
reproductive characteristics can be determined.
• Detailed studies of the effects of human disturbance should be made, especially for species that
breed near large coastal cities or marine recreation areas.

References

Bailey, E. P. 1973. Discovery of a Kittlitz's murrelet nest. Condor 75:457.

Binford, L., B. Elliott, and S. Singer. 1975. Discovery of a nest and the downy young of the
marbled murrelet. Wilson Bull. 87:303-319.
Bourne, W. 1972a. The decline of auks in Great Britain. Biol. Conserv. 4:144-146.
Bourne, W. 1972b. Threats to seabirds. Int. Counc. Bird Preserv. Bull. XI:200-218.
Couch, L. 1929. Introduced European rabbits in the San Juan Islands, Washington. J. Mammal.
10:334-336.
Drent, R. H., and C. Guiguet. 1961. A catalogue of British Columbia seabird colonies. Occas.
Pap. B. C. Prov. Mus. 12. 173 pp.
Franklin, J., and C. Dyrness. 1973. Natural vegetation of Oregon and Washington. U.S. For.
Serv. Gen. Tech. Rep. PNW-8. 417 pp.
Gabrielson, I., and F. Lincoln. 1959. The birds of Alaska. The Stackpole Company, Harrisburg,
Penn., and Wildlife Management Institute, Washington, D.C. 922 pp.
Grinnell, J. 1897. Petrels of Sitka, Alaska. Nidologist 4:76-78.
Grinnell, J. 1898. Summer birds of Sitka, Alaska. Auk 15:122-131.
Grinnell, J. 1909. Birds and mammals of the 1907 Alexander Expedition to southeastern Alaska.
Univ. Calif. Publ. Zool. 5:171-264.
Guiguet, C. 1971. A list of seabird nesting sites in Barkley Sound, British Columbia. Syesis
4:253-259.
Harris, M. P. 1970. Rates and causes of increases of some British gull populations. Bird Study
17:325-335.
Heath, H. 1915. Birds observed on Forrester Island, Alaska during the summer of 1913. Condor
17:20-41.
James-Veitch, E., and E. Booth. 1954. Behavior and life history of the glaucous-winged gull.
Walla Walla Coll., Publ. Biol. 12.
Jewett, S., W. Taylor, W. Shaw, and J. Aldrich. 1953. Birds of Washington State. Univ. of
Washington Press, Seattle. 767 pp.
Kadlec, J., and W. Drury. 1968. Structure of the New England herring gull population. Ecology
49:644-676.
Kenyon, K., and V. Scheffer. 1961. Wildlife surveys along the northwest coast of Washington.
Murrelet 42:29-37.
Manuwal, D. A. 1974. Conservation notes (Protection Island). Pac. Seabird Group Bull. 1.
Nettleship, D. 1972. Breeding success of the common puffin (Fratercula arctica L.) on different
habitats at Great Island, Newfoundland. Ecol. Monogr. 42:239-268.
Nettleship, D. 1973. Tenth census of seabirds in the sanctuaries of the north shore of the Gulf of
St. Lawrence. Can. Field-Nat. 87:395-402.
Patten, S. 1974. Breeding ecology of the glaucous-winged gull (Larus glaucescens) in Glacier
Bay, Alaska. M.S. Thesis. Univ. of Washington, Seattle. 78 pp.
Patten, S., and A. R. Weisbrod. 1974. Sympatry and interbreeding of herring and glaucous-
winged gulls in southeastern Alaska. Condor 76:343.
Richardson, F. 1961. Breeding biology of the rhinoceros auklet on Protection Island,
Washington. Condor 63:456-473.
Scott, J. M. 1971. Interbreeding of the glaucous-winged gull and western gull in the Pacific
Northwest. Calif. Birds 2:129-133.
Scott, M., W. Hoffman, D. Ainley, and C. Zeillemaker. 1974. Range expansion and activity
patterns in rhinoceros auklets. West. Birds 5:13-20.

Sealy, S. 1973. Breeding biology of the horned puffin on St. Lawrence Island, Bering Sea, with
zoogeographical notes on the north Pacific puffins Pac. Sci. 27:99-199.
Sealy, S. 1975. Feeding ecology of the ancient and marbled murrelets near Langara Island,
British Columbia. Can. J. Zool. 53:418-433.
Summers, K. 1974. Seabirds breeding along the east coast of Moresby Island, Queen Charlotte
Islands, British Columbia. Syesis 7:1-12.
Swarth, H. 1911. Birds and mammals of the 1909 Alexander Alaska Expedition. Univ. Calif.
Publ. Zool. 7:9-172.
Swarth, H. 1922. Birds and mammals of the Stikine River Region of northern British Columbia
and southeastern Alaska. Univ. Calif. Publ. Zool. 24:194-314.
Swarth, H. 1936. Origins of the fauna of the Sitkan District. Alaska. Proc. Calif. Acad. Sci. Ser.
4, 15:59-78.
Thoresen, A., and J. Galusha. 1971. A nesting population study of some islands in the Puget
Sound area. Murrelet 52:20-23.
U.S. Department of the Interior, Interagency Task Force. 1972. Environmental setting between
Port Valdez, Alaska, and west coast ports. Final Environmental Impact Statement, Vol. 3.
U.S. Weather Bureau. 1956. Climatic summary of the United States—supplement for 1931
through 1952, Washington. Climatography of the United States 11-39. 79 pp.
U.S. Weather Bureau, Environmental Data Service. 1965a. Climatic summary of the United
States—supplement for 1951 through 1960, Oregon. Climatography of the United States
86-31. 96 pp.
U.S. Weather Bureau, Environmental Data Service. 1965b. Climatic summary of the United
States—supplement for 1951 through 1960, Washington. Climatography of the United
States 86-39. 92 pp.
U.S. Weather Bureau, Environmental Data Service. 1974. Climatological Data, Alaska Annual
Summary 1974, 60:13.
Vermeer, K. 1963. The breeding ecology of the glaucous winged gull (Larus glaucescens) on
Mandarte Island. B.C. Occas. Pap. B.C. Prov. Mus. 13. 104 pp.
Vermeer, K., D. A. Manuwal, and D. S. Bingham. 1976. Seabirds and pinnipeds of Sartine
Island, Scott Island group, British Columbia. Murrelet 57(1):14-16.
Vermeer, K., and R. Vermeer. 1975. Oil threat to birds on the Canadian west coast. Can. Field-
Nat. 89:278-298.
Willett, G. 1912. Report of George Willett, Agent and Warden stationed on St. Lazaria Bird
Reservation, Alaska. Bird-lore 14:419-426.
Willett, G. 1915. Summer birds of Forrester Island, Alaska. Condor 19:15-17.
Williamson, F. S. L., and L. Peyton. 1963. Interbreeding of glaucous-winged and herring gulls in
the Cook Inlet region, Alaska. Condor 65:24-28.

FOOTNOTES:

[5] Data are minimum estimates of pairs and do not include breeding sites with less than 100 birds.
[6] Does not include the black oystercatcher, marbled murrelet, and western gull.
[7] Estimates only for colonies of 100 or more birds.
[8] Estimates are in number of pairs.
[9] Estimates are number of pairs.
[10] Estimates are numbers of pairs.
[11] Data for southeastern Alaska were inadequate to enable estimates of breeding pairs.

THE BIOLOGY AND ECOLOGY OF MARINE
BIRDS IN THE NORTH

Trophic Relations of Seabirds in the Northeastern Pacific Ocean and Bering Sea

by
David G. Ainley
Point Reyes Bird Observatory
Stinson Beach, California 94970
and
Gerald A. Sanger[15]
National Marine Fisheries Service
Marine Mammal Division
Seattle, Washington

Abstract

Literature on the diets of seabirds is reviewed for 70 species found in five subarctic
oceanographic regions of the northeastern North Pacific Ocean and Bering Sea. Species
inhabiting estuaries and sheltered bays are not included. The diets of cormorants, marine
ducks, alcids, and marine raptors are best known; less information is available for loons,
grebes, petrels, and gulls. Enough is known, however, to broadly characterize the diet of
each species. Less than 7% of all species feed on one type of prey, about 60% feed on two
or three types, and the rest feed on four or more types. Only 12% of all species feed on
eight or more types of prey. Most seabirds (77%) feed as secondary and tertiary carnivores.
Where overlap in diet exists, seabirds partition resources through use of different feeding
methods, selection of different-sized prey, and zonation of habitat. Species that have
specialized diets are probably more susceptible than others to local environmental
catastrophes. Species whose feeding methods are highly adapted for exploitation of
resources in polar and subpolar habitats are not adapted for coping with oil pollution.
Competition between birds and man for marine resources can sometimes benefit seabirds
and at other times harm them. More research is needed on seabird feeding relations so that
the ecological roles played by marine birds can be defined and placed in perspective. Such
work should be conducted at the community level, year-round, and should be so conducted
as to facilitate comparison with biological oceanographic data.
The ecology, morphology, and much of the behavior of a seabird species are definable in terms of the food
resources it exploits year-round and the spatial and temporal relations between food and breeding sites. This
general point unifies such important reports as those by Kuroda (1954), Bédard (1969a), Ashmole and Ashmole
(1967), Ashmole (1971), Spring (1971), and Sealy (1972). More concretely, information on trophic relations of
seabirds is useful in several ways. In conjunction with biological oceanographic data, it can provide insight into
geographic location, marine habitat, depth, time of day, and general method of food capture by seabirds. Collected
over several years, it can provide a basis for understanding annual differences in seabird breeding phenology and
success. Finally, supplemented with data on how much seabirds eat and excrete, it is necessary for an
understanding of the energetic and ecological roles played by the birds in the functioning of marine ecosystems.
Several studies that describe trophic relations within seabird communities have helped to define the principals of
community organization pertaining to the exploitation of available food resources and have given clues to food-
chain pathways. Trophic relations have been described for breeding communities in the Barents Sea (Uspenski
1958; Belopol'skii 1961), in the tropical Pacific Ocean (Ashmole and Ashmole 1967; Ashmole 1968), in the North
Sea (Pearson 1968), and in the Chukchi Sea (Swartz 1966). The last-named study pertained most directly to the
geographic region discussed in this paper, but several other studies have provided sound information on segments
of communities in the northeastern North Pacific and Bering Sea. These include the work on three species of
auklets (Aethia, Cyclorrhynchus) in the Bering Sea (Bédard 1969a); investigations on cormorants and other fish

predators in British Columbia by Munro (1941), Munro and Clemens (1931), and Robertson (1974); studies of
murres in Bristol Bay by Ogi and Tsujita (1973); observations on several species near the Pribilof Islands by Preble
and McAtee (1923); work on diving species off Oregon by Scott (1973); and studies of murrelets by Sealy (1975).
A review of available reports reveals three obvious gaps in the emphasis placed in seabird food studies. First, few
studies have ever considered in detail the trophic relations of seabird communities during the winter or
nonbreeding season. Partial exceptions are the works by Cottam (1939) and others on marine diving ducks, species
that are seabirds only during the winter, and by several researchers (Munro and Clemens 1931; Munro 1941;
Robertson 1974) on seabirds in British Columbia. Divoky (1976) studied diets of pack-ice gulls during the
nonbreeding season, but those species are not included in the present analysis because they rarely are found south
of the Bering Strait. Second, no study has considered the trophic relationships of an entire seabird community, i.e.,
not just breeding species but also nonbreeding species. In the rather broad communities considered here, 50-70%
or more of the birds breed in another part of the world. To say that these nonbreeding species have no significant
impact on resource exploitation or on organization and evolution among breeding members would be naive.
Finally, few investigators have attempted to fit birds into an entire ecosystem, including lower trophic level origins
as well as fish, marine mammals, and man.
The reasons for these gaps in study emphasis are readily apparent: the inconvenience of marine research during the
winter when weather is stormy, the need for costly study platforms (boats), and the difficulties in organizing the
specialized community of biologists required for such tasks. A less obvious but important reason is that
oceanographers and fishery biologists have overlooked seabirds as important members of marine ecosystems.

Diets of Seabirds in Western North America

Relatively good information exists for most pelecaniformes of the region. A notable exception is the brown pelican
(Pelecanus occidentalis), an endangered species. This is unfortunate because dietary information is important for
understanding the species' ecology. Observations in eastern North America (Palmer 1962) and Peru (Murphy 1936)
indicated that their diet consisted of fish that occur at the surface. The larger cormorants are piscivorous,
particularly on schooling fishes that occur at moderate to great depths (Table 1). The smaller cormorants feed more
heavily on benthic fish and decapod crustaceans. Cormorants apparently feed only during daylight and then only
for short periods because their wettable plumage loses its buoyancy. Thus they remain relatively close (50 km) to
nesting and loafing areas.

Table 1. Food of cormorants in different localities (x = major prey, o = minor prey and * = incidental prey
species)
Di­‐
et
CRUS­‐
TA­‐
CEAN FISH
G P
a H l
A P O B M s e E e
E r o t o i t x m S A u
A n S g r o r c e S a b O t m r
m D g a e i p e r r e g i C x i m o
p I e C r l n c h o o o b r C A o h y c P G o n B
h s c l a m t h i g g s a a o g t r j h h o d e o
i o a u u o i t d a a t s m t o o o u a o b y c t
p p p p l n n h i d d e t m t n c m l c l i t t h
o o o e i i i y u u u u e i i i i i i i i i e i i
Lo­ca­tion d d d a s d d s m s s s s d d d d s s d d d s d d
Double-crested
cormorant
(Phalacrocorax auritus)
[16]

Alaska Peninsula
o o o x x x o x
(Palmer 1962)
SE Alaska (Bailey
x
1927)
Mandarte Island
* * * * * * o x x
(Robertson 1974)
Vancouver Island
(Munro and Clemens x
1931)
Oregon (Palmer 1962) x * * x * x * *
Farallon Island
(PRBO, unpublished * * * x * * *
data)
Brandt's cormorant (P.
penicillatus)[17]
Vancouver Island
(Robertson, x o x
unpublished data)
Vancouver Island
(Munro and Clemens x
1931)
Washington (Jewett et
x
al. 1953)
Yaquina Head (Scott
x o o * o o o
1973)
Farallon Island
(PRBO, unpublished * o * * x x x * o * * *
data)
San Diego (Hubbs et
* * o o * x
al. 1970)
Pelagic cormorant (P.
pelagicus)[18]
Cape Thompson
x x x x
(Swartz 1966)
Pribilof Island (Preble
x x x
and McAtee 1923)
Alaska (Palmer 1962) x x x x x x x x x
SE Alaska (Heath
x x x
1915)
Mandarte Island
x * * x x
(Robertson 1974)
Vancouver Island
(Munro and Clemens x x x x x x
1921)
Washington (Jewett et
x x x x
al. 1953)
Netarts, Oregon
(Gabrielson and * * x x
Jewett 1940)
Yaquina Head (Scott
o o x
1973)
Farallon Island
(PRBO, unpublished x x x x
data)

Red-faced cormorant (P.
urile)
Pribilof Islands
(Preble and McAtee x x x x x x
1923)

Table 2. Food of marine ducks and geese (x = major prey, o = minor prey, and * = incidental prey species).[19]
Diet[19]
PLANTS CRUS­TA­‐ ECHI­‐ FISH FISH
CEANS MOL­LUSCS NO­‐ EGGS
Oys­‐ DERMS
Am­‐ Dec­‐ Bar­‐ ters, Lit­‐
phi­‐ a­‐ na­‐ Mus­‐ Rock Ra­zor Scal­‐ tor­i­‐ Chi­‐
Location pods pods cles sels clams clams lops nids tons
Geese x
(Branta spp.)
Emperor goose x
(Philacte
canagica)
Oldsquaw o * * * * * * * o
(Clangula
hyemalis)
Harlequin duck * x x o * * o o * *
(Histrionicus
histrionicus)
Steller's eider o x * * * * o * * * *
(Polysticta
stelleri)
Common eider * * x * o * o o * o *
(Somateria
mollissima)
King eider * * o * x * o o * x *
(S. spectabilis)
Spectacled eider x * x o * * * *
(S. fischeri)
White-winged * * o o
* * * o x * x o *
scoter
(Melanitta
deglandi)
Surf scoter o * * * x * * x o * * * o
(M.
perspicillata)
Black scoter o * * o x * * x * * * *
(M. nigra)
Red-breasted x
merganser
(Mergus
serrator)

Information on diets of marine ducks (Table 2) is more nearly complete than for most other seabirds. These birds
fall into four groups with some overlap: species feeding on plants (Branta, Philacte, Anas-type, and Somateria
fischeri); those feeding on benthic crustaceans (Clangula hyemalis, Histrionicus histrionicus, Polysticta stelleri, S.
mollissima); those feeding on benthic molluscs (Somateria spp. and Melanitta spp.); and those feeding on fish

(Mergus serrator, Clangula hyemalis, and Melanitta deglandi). A study by Perthon (1968), one of the few on a
seabird's diet during most of a year, showed a seasonal change in diet for S. mollissima in Norway. In general,
waterfowl seem to specialize in their diets much more than other seabirds and, for that reason, are perhaps more
restricted in their distributions. Some marine ducks are known to dive to considerable depths (reviewed by
Kooyman 1974), but usually they occur in shallow waters where plants and sessile invertebrates are readily
available.
The summer diet of the pigeon guillemot (Cepphus columba) is the best known among seabirds in the region being
considered here (Table 3). Only in the extreme southern part of its range (i.e., the California Channel Islands) is
there no information available on its diet. The species feeds on organisms, mostly fish, from rocky habitat and
apparently can dive to considerable depths (Follett and Ainley 1976). Because so much is known about guillemot
diets during summer, a study of the winter diet would be valuable.
The diets of other alcids are known well enough to at least characterize them broadly. The larger species, murres,
tufted and horned puffins (Lunda cirrhata, Fratercula corniculata), and the rhinoceros auklet (Cerorhinca
monocerata), feed heavily on fish, mainly species that school in midwater (Table 4). To a great degree, these birds
are opportunistic, feeding rather heavily at times on cephalopods and crustaceans, particularly nektonic forms.
Morphological differences between the two murre species suggest that thick-billed murres (Uria lomvia) feed on
benthic organisms much more than do common murres (U. aalge), and that the latter species is more piscivorous
(Spring 1971); however, field data on diets are barely adequate to confirm this. Ogi and Tsujita (1973) analyzed
the stomach contents of murres drowned in salmon gill nets but did not separate the two species. For the present
paper we considered them to be mostly U. aalge, since this species predominates in the region of the food study
(Bartonek and Gibson 1972). Adult murres sometimes eat different items than they feed to their chicks (Spring
1971; Scott 1973). The smaller alcids, ancient and marbled murrelets—Synthliboramphus antiquus and
Brachyramphus marmoratus—(Table 5) and auklets (Table 6), feed on macrozooplankton: crustaceans, and fish
and squid larvae. Little is known about the food or feeding ecology of Kittlitz's murrelet (B. brevirostris). Its diet is
probably similar to that of the other murrelets, especially the marbled murrelet, its allopatric congener, but the diets
of the other murrelets differ somewhat (Bédard 1969b; Sealy 1975). The Kittlitz's murrelet's shorter bill suggests
that it feeds more on invertebrates. Alcids feed in deep or shallow water, depending on food distribution. Some
alcid species can be found at great distances from land, particularly in winter (Hamilton 1958; Scott et al. 1971).
Information on the diets of other seabirds in the region is fragmentary and sometimes rather anecdotal. A little is
known about the feeding habits of loons (Gavia spp.) and grebes (Podiceps spp. and Aechmophorus occidentalis),
especially off British Columbia (Table 7). The larger of these birds feed mainly on inshore fish, but as species
become progressively smaller, there is a tendency toward eating crustaceans. Work by Madsen (1957) in Denmark,
indicated that loons and grebes tend to take prey near or on the bottom. Much more information is available on
these birds' diets at their freshwater breeding sites but this provides only partial insight into what they might eat in
marine habitats.
Information is especially poor for albatrosses and petrels (order Procellariiformes) (Table 8). Yet, based on sheer
numbers alone, members of this diverse group are easily among the most ecologically dominant of the region
(Sanger 1972; Ainley 1977). The Laysan albatross (Diomedea immutabilis) seems to be a squid specialist; the
black-footed albatross (D. nigripes), northern fulmar (Fulmarus glacialis), scaled petrel (Pterodroma inexpectata),
and the fork-tailed and Leach's storm-petrels (Oceanodroma furcata and O. leucorhoa) appear to be large,
medium, small, and tiny versions, respectively, of surface-feeding generalists that eat whatever they can find,
including live and dead fish, squid, coelenterates, crustaceans, and other organisms. The shearwaters (Puffinus
spp.) feed to an unknown degree on schooling fish, squid, and crustaceans that occur near the surface. For these
very abundant shearwaters, that, unfortunately, is close to the extent of our knowledge both for the North Pacific,
where they winter, and the South Pacific, where they breed. Most petrels remain in oceanic habitats, but
shearwaters, particularly the sooty shearwater (Puffinus griseus), and sometimes fulmars feed close to, if not
within, the inshore neritic habitat. A much better understanding of the diets of this group is sorely needed.

Table 3. Food of the pigeon guillemot (Cepphus columba) in different localities (x = major prey, o = minor
prey, and * = incidental prey species).
Lo­ca­tion Di­‐
et
CRUS­‐ O
TA­CEAN C FISH

T C
O r
P P B y C
U e G a p e P
S t a t t b l
r s S E h a i A e
o C t c m y c d S m u
A m h e o b m a i t m r
m D y i C O r r i a n c i o o
p I e z m l s o p C A o s C t h c P n B n
h s c o a u m G s a o g t t l h t h h d o e
i o a n e p e a t e t o o e i o h a o y t c
p p p t r e r d e n t n c r n d y e l t h t
o o o i i i i i i i i i i i i i i i i i i i
d d d d d d d d d d d d d d d d d d d d d d
Cape Thompson (Swartz 1966) o o
Pribilof Island (Preble and
o o o
McAttee 1923)
Mandarte Island (Drent 1965;
o o * o x o o * o * o o o o o o
Koelink 1972)
Vancouver Island (Munro and
o o o
Clemens 1931)
Olympic Peninsula (Thoresen
o o o o
and Booth 1958)
Yaquina Head (Scott 1973) o o o o o
Farallon Island (Follett and
o o * x x * o o o o
Ainley 1976)
Knowledge on the food of gulls, shorebirds, and related species is surprisingly scanty in view of all that is known
about their breeding biology and social behavior. Little is known about the marine food of phalaropes, but by
inference from their association with storm-petrels, plankton-feeding whales, and convergence lines (Martin and
Myers 1969), their tiny size, and their method of feeding (picking at minuscule items on the water surface), one
can guess that they feed on zooplankton and detritus. Skuas (Catharacta skua) and jaegers (Stercorarius spp.)
apparently eat what they can find at the surface, as well as whatever they can steal from gulls and terns. Almost all
the literature on their feeding (Bent 1946) dwells on accounts of their stealing from other birds. That spectacular
behavior would seem to be so energetically costly, though, that it is probably less important than we have been led
to believe. Rather surprisingly, the question of what foods the gulls and terns eat in the eastern North Pacific is
difficult to answer from the literature (Tables 9 and 10). Some information exists for five of the larger larids at
isolated places, but little is known about food elsewhere in their respective ranges, and the diets of the seven
smaller gulls and the terns are practically unknown. Studies on gull diets in the Atlantic region (e.g., Spaans 1971;
Harris 1965) provide information on what to expect from the same species in the Pacific, but that information must
be considered only in general terms because, the birds being somewhat opportunistic, their diets differ greatly from
one locality to another (Ingolfsson 1967). A few observations are available for arctic terns (Sterna paradisaea) in
Alaska, but little information exists for other terns (Table 10). Bent (1921) noted that Aleutian terns (S. aleutica)
sometimes associate with arctic terns during feeding.
Finally, we must include raptors, particularly the peregrine (Falco peregrinus) and bald eagle (Haliaeetus
leucocephalus), because they are important predators on the smaller seabirds (White et al. 1971, 1973). Peregrines
have, in fact, been observed feeding on storm-petrels far at sea (Craddock and Carlson 1970).

Trophic Relations Within Seabird Communities

We have compared and summarized in general terms the food partitioning by species in five rather broad
oceanographic regions and their subdivisions in the northeastern North Pacific and Bering Sea, based on the
specific details on diets presented in Tables 1 through 10. The five broad regions, defined oceanographically by
Dodimead et al. (1963) and Favorite et al. (1976) and modified by Sanger (1972), are shown in Fig. 1. The five

oceanographic regions (domains) were divided further into inshore neritic, offshore neritic, and oceanic habitats
(Sanger and King, this volume). We did not include estuarine habitats or sheltered bays in the analysis.

Fig. 1. Schematic oceanographic domains of the subarctic Pacific regions
(defined by Dodimead et al. (1963) and Favorite et al. (1976) and modified by
Sanger (1972).)

Table 4. Food of murres and puffins in different localities (x = major prey, o = minor prey, and * = incidental
prey species).
Diet
CRUS­TA­‐ P C
CEAN O E FISH
L P O M
Y H n T G y C P
C A c h a o y C l
E H L h a B M s x m E h e
u A O S E o H l o i t o a m i S A u
p A E P a n r y e M r c T e T c t b r t m r
h m D T O r g h p i a e r h L r S r e o i o i m o L
a p I e E D C d r y o c l o o e y o e i p C g o l c o n i
u h s c l i a S n m h l g g r c s b g h o a t o h d e p
s i o a u n u a c e t o a a a o t a l a t s o p a y c a
i p p p p o l l h s h t d d g d e s o l t t c h e t t r
i o o o e p i m u u y u u u r e u t p u i e i i i e i i
LOCATION d d d d a s s o s s s s s s a s s e s s d r d s d s d d
Common
murre(Uria
aalge)[20]
Cape
Thompson
o o o o o x o o o x
(Swartz
1966)
Pribilof
Islands
(Preble and x o o o
McAtee
1923)

E. Bering
Sea (Ogi
x o x x x
and Tsujita
1973)
Forrester
Island
o o x
(Heath
1915)
Vancouver
o o x o
Island
(Robertson,
unpublished x x o o
data)
Olympic
Peninsula
x x o x o o o
(Cody
1973)
Yaquina
x o
Head
(Scott
x o o * x o o
1973)
Farallon
Islands
(PRBO, x o
unpublished
data)
Thick-billed
murre x o o o o o x o
(U. lomvia)[21]
Cape
Thompson
o o o
(Swartz
1966)
Pribilof
Islands
(Preble and x x
McAtee
1923)
Hooker
x o
Island
(Demme
1934, in
o x * x * o x o o o
Dement'ev
et al. 1968)
NE Canada
(Tuck and
x o o o
Squires
1937)
Tufted puffin x
(Lunda
*
cirrhata)[22]
Cape
*
Thompson

(Swartz
x
1966)
Forrester
Island
x
(Heath
1915)
Langara
x
Island
(Sealy
x x x x
1973a)
Washington o
(Jewett et
x o x
al. 1953)
Olympic
x
Peninsula
(Cody
x o
1973)
Farallon
Island
(PRBO, x
unpublished
data)
Horned
x o
puffin
(Fratercula
o x
corniculata)
Cape
Thompson
o
(Swartz
1966)
Alaska
x
(Bent 1946)
Forrester
Island
(Heath
1915)
Rhinoceros
auklet
x o x x
(Cerorhinca
monocerata)
NW Pacific
(Kozlova x
1961;
Komaki
x
1967)
Forrester
Island
x
(Heath
1915)
Langara
Island
o x
(Sealy
1973a)

Destruction
o
Island
(Richardson
x x o
1961)
Olympic
Peninsula
x
(Cody
1973)
So.
California
(Linton
x
1908;
Grinnell
1899)

Table 5. Food of ancient and marbled murrelets (x = major prey, o = minor prey, and * = incidental prey species).
DIET
SQU­‐
CRUSTACEAN ID FISH
A­‐ Cy­‐
Thy­‐ can­‐ ma­‐ Am
Eu­‐ sa­‐ Eu­‐ tho­‐ Am­‐ Gam­‐ Dec­‐ En­‐ Os­‐ Scor­‐ to­‐ Sti­‐ mo­
phau­‐ noes­‐ phau­‐ My­‐ my­‐ phi­‐ ma­‐ Ca­rid a­‐ Lar­‐ Lar­‐ gra­u­‐ mer­‐ paen­‐ ga­‐ chae­‐ dy­‐
Location si­id sa sia sid sis pod rid shrimp pod vae vae lis id id ster id tes
Ancient murrelet
(Synthliboramphus
antiquus)[23]
Commander
Islands
x x
(Dement'ev et
al. 1968)
Amchitka Island
(White et al. x x x x x
1971, 1973)
Langara Island
x x x * * * o o x
(Sealy 1975)
Marbled
murrelet
(Brachyramphus
marmoratus)[24]
SE Alaska
o
(Grinnell 1897)
Langara Island
x x * * * * x *
(Sealy 1975)
Vancouver
Island (Munro
x x
and Clemens
1931)
Olympic
Peninsula (Cody x x
1973)

Table 6. Diets of auklets in different localities (x = major prey, o = minor prey, and * = incidental prey species).

Diet
CRUSTACEAN PO­LY­‐ SQUID FISH
Pa­‐ CHAE­‐
Thy­‐ Sty­‐ ra­‐ TE
Eu­‐ sa­‐ lo­‐ Am­‐ the­‐ Co­‐ Ca­‐
pha­‐ noes­‐ My­‐ my­‐ phi­‐ mi­‐ Phro­‐ Gam­‐ pe­‐ la­‐ Ca­rid Cot­‐ Lar­‐
Location u­si­id sa sid sis pod sto ne­ma ma­rid pod nus shrimp Lar­vae tid vae
Cassin's auklet
(Ptychoramphus
aleuticus)
Forrester Island
x x x
(Heath 1915)
Olympic
Peninsula (Cody x x
1973)
Farallon Islands
x x x x x o x
(Manuwal 1974)
Parakeet auklet
(Cyclorrhynchus
psittaculus)
Chukhotsk
Peninsula
(Portenko 1934, x x xx x
in Dement'ev et
al. 1968)
Aleutian Islands
x
(Bent 1946)
St. Lawrence
Island (Bédard x x o x x o o * o o o
1969a)
Crested auklet
(Aethia cristatella)
[25]

W. Bering Sea
(Portenko 1934,
x x
in Dement'ev et
al. 1968)
Commander
Islands (Stejneger x
1885)
Amchitka (White
x x x x x
et al. 1973)
St. Lawrence
Island. (Bédard x x x oo x x *
1969a)
Pribilof Islands
(Preble and x x
McAtee 1923)
Least auklet (A.
pusilla)
Commander
Islands (Stejneger x
1885)

Aleutian Islands
x
(Bent 1946)
St. Lawrence
Island (Bédard o o * o o o x x x
1969a)
Whiskered auklet
(A. pygmaea)
Commander
Islands (Stejneger x x *
1885)

Table 7. Diets of loons and grebes in different localities (x = major prey, o = minor prey, and * = incidenta
species).
Diet
CRUSTACEANS PO­LY­‐ FISH
CHAE­‐ Ga­‐ Cy­‐
TE Tha­‐ A­‐ ste­‐ ma­‐ Am
Eu­‐ Am­‐ De­‐ An­‐ Sar­‐ le­‐ the­‐ Zo­‐ Fun­‐ ro­‐ Se­‐ to­‐ Sti­‐ mo
pha­‐ phi­‐ My­‐ ca­‐ gu­il­‐ Cla­‐ di­‐ Sal­‐ ich­‐ ri­‐ ar­‐ Ga­‐ du­‐ ste­‐ ba­‐ Cat­‐ ga­‐ chae­‐ dy
Location us­id pod sid pod la pea nops mo thys nops chid did lus us stes tid ster id te
Common loon
(Gavia immer)
Alaska
(Palmer * * o o o o o
1962)
Vancouver
Island
(Munro and x
Clemens
1931)
Denmark
(Madsen * o x * o
1957)
Yellow-billed
loon (G.
adamsii)[26]
Alaska
(Cottam and
* * o x
Knappen
1939)
Alaska
(Bailey x
1922)
Arctic loon (G.
arctica)[27]
Vancouver
Island
x
(Palmer
1962)
Vancouver
Island
(Robertson, x
unpublished
data)

California
(Palmer x
1962)
Denmark
(Madsen * o * x x * x
1957)
Red-throated
loon (G.
stellata)[28]
Oregon
(Palmer x
1962)
No. Atlantic
(Palmer x x o
1962)
Denmark
(Madsen * o * x o * *
1957)
Western grebe
(Aechmophorus
occidentalis)
Vancouver
Island
o * x x
(Munro
1941)
Vancouver
Island
(Robertson, x x
unpublished
data)
Puget Sound
(Phillips and x * o o o
Carter 1957)
Washington
(Chatwin * x
1956)
California
(Palmer o * x x x *
1962)
Red-necked
grebe
(Podiceps
grisegena)
Pribilof
Islands
(Preble and o
McAtee
1923)
Vancouver
Island
x
(Wetmore
1924)
Vancouver x o x
Island

(Munro
1941)
E. No.
America
o * o o x
(Wetmore
1924)
Horned grebe
(P. auritus)[29]
Pribilof
Islands
(Preble and x o
McAtee
1923)
W. No.
America
x x * o o
(Wetmore
1924)
Vancouver
Island
x x o o *
(Munro
1941)
Denmark
(Madsen o o o
1957)
Eared grebe
(P. nigricollis)
[30]

W. No.
America
* x * o
(Wetmore
1924)
Vancouver
Island
x x o
(Munro
1941)
Denmark
(Madsen x *
1957)

Table 8. Diets of albatrosses and petrels in different localities (x = major prey, o = minor prey, and * =
incidental prey species).
Diet
CRUSTACEAN COE­‐ E­CHI­‐ CE­‐ FISH
LEN­‐ NO­‐ PHA­‐ Am­‐ Car­‐
Eu­‐ Am­‐ Co­‐ De­‐ Bar­‐ TE­‐ DERM LO­‐ En­‐ My­‐ Se­‐ mo­‐ ri­on,
pha­‐ phi­‐ pe­‐ ca­‐ Lar­‐ na­‐ RA­TE POD grau­‐ cto­‐ ba­‐ dy­‐ fish Fish
Location u­si­id pod pod pod vae cle "Fish" lis phid stes tes of­fal eggs
Black-footed
albatross
(Diomedea nigripes)
No. Pacific
x x x
(Palmer 1962)
Aleutian Islands o x o x x
(Cottam and

Knappen 1939)
California (Miller
o o x x x x
1936, 1940)
Laysan albatross
(D. immutabilis)
No. Pacific
(Palmer 1962;
x
Bartsch 1922;
Fisher 1904)
Northern fulmar
(Fulmarus glacialis)
Pribilof Islands
(Preble and o x
McAtee 1923)
Alaska
(Gabrielson and x x x
Lincoln 1959)
Oregon
(Gabrielson and x
Jewett 1940)
No. Atlantic
(Hartley and
Fisher 1936; x x
Einarsson 1945;
Fisher 1952)
Flesh-footed
shearwater
(Puffinus carneipes)
Australia (Oliver
1955; Serventy et x x x
al. 1971)
Pink-footed
shearwater (P.
creatopus)
California
(Murphy 1936;
x x
Ainley, personal
observation)
E. Pacific (Cottam
and Knappen x x
1939)
Buller's shearwater
(P. bulleri)
SW Pacific (Falla
1934; Serventy et x x x
al. 1971)
Peru (Murphy
x
1936)
Sooty shearwater
(P. griseus)
Aleutian Islands
(Sanger, personal x x x
observation)

British Columbia
(Martin 1942; x x x
Sealy 1973a)
Oregon
(Gabrielson and x
Jewett 1940)
California (Ainley,
personal x x
observation)
Peru (Murphy
x x x
1936)
SW Pacific
(Oliver 1955;
x x x
Serventy et al.
1971)
Short-tailed
shearwater (P.
tenuirostris)
Bristol Bay
(Bartonek,
x
personal
communication)
Alaska (Cottam
and Knappen x x x o
1939)
No. Pacific
(Palmer 1962; x x x
Kuroda 1955)
Australia
(Serventy et al. x x x
1971)
Bass Strait
x
(Sheard 1953)
Mottled petrel
(Pterodroma
inexpectata)
Pacific Ocean
x
(Imber 1973)
E. No. Pacific
x
(Kuroda 1955)
Fork-tailed storm-
petrel
(Oceanodroma
furcata)
Pribilof Islands
(Preble and x
McAtee 1923)
SE Alaska (Heath
x
1915)
British Columbia
x
(Martin 1942)
California (Ainley,
personal x
observation)

Leach's storm-
petrel (O.
leucorhoa)
SE Alaska (Heath
x
1915)
California (PRBO,
x x x x x
unpublished data)
So. California
x x
(Palmer 1962)
No. Atlantic[31]
x x x x x
(Palmer 1962)

Table 9. Diets of gulls in different localities (x = major prey, o = minor prey, and * = incidental prey species).
Diet
CRUSTACEAN P MOLLUSC E C FISH C BIRD F
O CO M A I
L HE y R S
E Y C I L PO BM x GE R H
u C S e NE E o t o i o e mA I
p B H h p ON n r aMr c S c n b mO E
h a D A e h DT g O i p a r r Le e y i mN G
a r e E l a E E "C r s c h l o o y b p o o o - CAG
u n c T l l R RF l a mh i l g g G c a h n t d O h d S
s a a E f o MA i u u e i d o a a a o s a e o y F E i u
i c p i p Tsp l rh i t d d ddt l mc t Fg c l
i l o s o Eh e i u y u u u u u e e u u i e A g k t
Location d e d h d "a s s sm s s s s s s s s d s L s s s
Glaucous gull (Larus
hyperboreus)
St. Lawrence Island (Fay and
xxx
Cade 1959)
Chukchi Sea (Swartz 1966) x x x x xxx
Pribilof Islands (Preble and
x x xx x
McAtee 1923)
Vancouver Island (Munro and
x x
Clemens 1931)
Glaucous-winged gull (L.
glaucescens)[32]
Pribilof Islands (Preble and
x x x xxxx
McAtee 1923)
Alaska (Bent 1921) x
No. Pacific (Sanger 1973) x * *
Mandarte Island (Ward 1973) x x x xx
Vancouver Island (Munro and
Clemens 1931; Robertson, x x x
unpublished data)
Western gull (L. occidentalis)
[33]

Farallon Islands (PRBO,
x x o * x * * x xo o o x o o xooo
unpublished data)
Herring gull (L. argentatus)
No. Atlantic (Zelikman 1961) x

E. No. America (Bent 1946;
x x x x x x* ox
Ainley, personal observation)
Vancouver Island (Munro and
x x x
Clemens 1931)
Mew gull (L. canus)
Alaska (Bent 1921) x x x x
Vancouver Island (Munro and
x x x
Clemens 1931)
Heermann's gull (L.
heermanni)
California (Bent 1921) x x x x
Bonaparte's gull (L.
philadelphia)
E. No. America (Bent 1921) x x x
Black-legged kittiwake (Rissa
tridactyla)[34]
Chukchi Sea (Swartz 1966) o * o ox o o x
Pribilof Islands (Preble and
o x o
McAtee 1923)
Alaska (Bent 1921) x o
Cook Inlet[35] (Snarski, o o o x o x
personal communication)
No. Atlantic (Hartley and
x
Fisher 1936; Zelikman 1961)
Red-legged kittiwake (R.
breuirostris)
Pribilof Islands (Preble and
x x x
McAtee 1923)
Sabine's gull (Xenia sabini)
Pt. Barrow (Banner 1954) x

Table 10. Diets of terns in different localities (x = major prey species).
Diet
CRUSTACEAN FISH
Ammodytes
Location "Crustacean" MallotusEuphausiid Cottid Amphipod larvae
Arctic tern (Sterna paradisaea)
Pribilof Islands (Preble and McAtee 1923) x x
Alaska (Bent 1921) x x x
No. Atlantic (Hartley and Fisher 1936) x
Common tern (S. hirundo)
E. No. America (Bent 1921) x x

The oceanic habitat includes waters of the photic zone overlying the deep ocean and continental slopes beyond the
continental or insular shelves. The Bering Sea and central subarctic domains are largely made up of oceanic
habitat. The other three domains include both inshore and offshore neritic as well as some oceanic habitat. The
boundary between the inshore and offshore neritic has yet to be defined in terms of bird life, but it lies at that line
beyond which the bottom is too deep for a diving bird to exploit. A depth contour thus defines the boundary. In the
antarctic South Pacific, emperor penguins (Aptenodytes fosteri) dive to depths of 275 m, but so far as is known, no
comparable bird exists in the North Pacific. Some marine ducks and loons reportedly dive to 50-60 m (Kooyman
1974). The inshore-offshore neritic boundary for seabirds may lie near the 70-m depth contour.

Food resource partitioning by seabirds in the five oceanographic domains are shown in Tables 11-15. Within each
domain, the common and usual members of the seabird community are listed, and the major and minor categories
in each of their diets are shown (on the basis of available literature, Tables 1-10). The categories are grouped
further, and rather tenuously, according to the trophic level at which a bird is presumably feeding: I = herbivore, II
= secondary carnivore, III = tertiary carnivore, IV = final carnivore, and Sc = scavengers (carnivorous) feeding at
many levels. Birds at level I feed on large algae and seed plants and are not directly part of the same food webs
involving other species. These food webs originate with phytoplankton (Fig. 2). So far as is known, no bird feeds
on phytoplankton and few, if any, feed on microzooplankton; hence birds do not generally feed as primary
carnivores. An exception at times might be the least auklet (Aethia pusilla) when it feeds on small copepods (see
Bédard 1969b).
The above groupings are "tenuous" because prey in each category may represent more than one trophic level, and a
single prey species could occur at one level one day or place and at another level the next day or place, depending
upon what it happened to be eating. This is shown in Fig. 2, where the parakeet auklet (Cyclorrhynchus
psittaculus) can occur in the food web at different levels, depending both on the prey it is eating and on what its
prey is eating. Even without this complication, many seabirds feed at more than one level in the food web. For
instance, murres eating euphausiids would be feeding at a different level than murres feeding on larger fish. It
might be "safer" to regard prey organisms in level II as macrozooplankton, prey organisms in level III as
micronekton, and prey organisms (seabirds themselves) in level IV as macronekton (after Sverdrup et al. 1942).

Fig. 2. Schematic food web of the parakeet auklet in the eastern Bering Sea
(based on Bédard 1969a and Dunbar 1946). Arrow sizes indicate relative
importance of prey and Roman numerals refer to prey sizes (see text).

Table 11. Use of food resources by seabirds in the Bering Sea coastal domain. Information is from Tables 1-10.
(Trophic level I = plants, II = secondary carnivore, III = tertiary carnivore, IV = upper level carnivore
[on birds only in this table], Sc = scavenger on carrion, offal, or detritus [II-IV]; x = major food in diet,
o = minor food, * = incidental food, ? = probable food.)
Seabirds Habitat, bird trophic levels (I-IV.
Sc), and food categories
Inshore
Oceanic and offshore neritic neritic
II III IV Sc I II III IV Sc
C PC F FC B C P C CC E M F F FC B C
r oo i i e i a l r ro c o i i i e i a

u l e s sp r r a u ueh l s s sp r r
s y l hhh d r n s s l i l h hhh d r
t ce / a s i t t t en u / , ,a s i
a hn s l o a ano s s l o
c at q o n c c t d c q mb o n
e eeu p / e e e e u i ep /
a tr i o o a ar r i dno o
n ead d f n n am d w t d f
t f , , t ah f
e e a e e t i a
g l m b g ec l
g / i e g r /
s d d n s d
e w t e
& t a h & t
r t i r
l i e c l i
a t r a t
r u r u
v s v s
a a
e e
Gavia adamsii * ox
G. arctica ox
Podiceps grisegena o ox
Diomedea nigripes x oo oxx x
Fulmarus glacialis x ox oxx x
Puffinus griseus x xx o o
P. tenuirostris x ox o o
Oceanodroma furcata x oo xxx x
Phalacrocorax auritus o xo
P. pelagicus x x
P. urile x x
Branta bernicla x
Philacte canagica x
Clangula hyemalis o x o o
Histrionicus
o x o
histrionicus
Polysticta stelleri o x o o
Samateria mollissima x o x
S. spectabilis o o o x
S. fischeri x x
Melanitta deglandi x o
M. nigra o o x
Haliaeetus
x x x
leucocephalus
Falco peregrinus x
Phalaropus fulicarius x x o x x
Lobipes lobatus x x o x x
Stercorarius spp. o xx ? x x x x
Larus hyperboreus o ooo o ooo o o x x x
L. glaucescens o ooo o ooo o o x x x
L. argentatus o ooo o ooo o o x o x

L. canus xoo o x x
Rissa tridactyla x xx o
Xema sabini x xoo
Sterna paradisaea x xoo
Uria aalge x o xx o o xo
U. lomvia x o xx o x ox
Lunda cirrhata ? xx
Fratercula corniculata * xx
Cepphus columba o xo
Synthliboramphus
x x o
antiquus
Brachyramphus
x o
brevirostris
Cyclorrhynchus
x o **
psittaculus
Aethia cristatella x x
A. pusilla x o

Table 12. Use of food resources by seabirds in the oceanic and offshore neritic habitats, Bering Sea domain.
Information is from Tables 1-10. (Trophic level I = plants, II = secondary carnivore, III = tertiary
carnivore, IV = upper level carnivore; Sc = scavenger on carrion, offal, or detritus [II-IV]; x = major
food in diet, o = minor food, * = incidental food, ? = probable food.)
Bird trophic
levels and food
categories
II III IV Sc
Cru­sta­ce­an Po­ly­‐ Coe­‐ Fish/Squid Fish Ce­‐ Birds Car­ri­‐
chae­te len­te­‐ eggs & Lar­‐ pha­‐ on/of­‐
ra­te vae lo­pod fal/de­tri­‐
Seabirds tus
Diomedea nigripes x o o o x x x
D. immutabilis x
Fulmarus glacialis x o x o x x x
Puffinus griseus x x x
P. tenuirostris x o x
Pterodroma
x x
inexpectata
Oceanodroma
x o o x x x x
furcata
Phalaropus
x x o
fulicarius
Lobipes lobatus x x o
Stercorarius spp. o x x ? x
Larus hyperboreus x o o o x x ? x
L. glaucescens x o o o x x ? x
Rissa tridactyla x x x o
R. brevirostris x x x o
Xema sabini x x o o
Sterna paradisaea x x o o
Uria aalge x o x x
U. lomvia x o x x
Lunda cirrhata ? x x

Fratercula
* x x
corniculata
Synthliboramphus
x x
antiquus
Cyclorrhynchus
x o * *
psittaculus
Aethia cristatella x x
A. pusilla x o
A. pygmaea x
Information contained in Tables 11-15 can be summarized to show characteristics of seabird trophic relations. One
such characteristic is the range of diet breadth or diet complexity (Table 16). Few species (about 6%) feed on only
one type of prey and might, therefore, be referred to as "specialists." Included are eared grebe (Podiceps caspicus),
Laysan albatross, brown pelican, emperor goose (Philacte canagica), black brant (Bernicia bernicla), peregrine
falcon, and whiskered auklet (Aethia pygmaea). Consideration of these species as specialists may require revision
when more data become available. Except for the albatross and auklet, these species are members of the inshore
neritic cohort. Food specialization does not seem to be characteristic of oceanic birds in particular or of most
seabirds in general.

Table 13. Use of food resources by seabirds in the Alaska Stream domain. Information is from Tables 1-10.
(Trophic level I = plants, II = secondary carnivore, III = tertiary carnivore, IV = upper level carnivore,
Sc = scavenger on carrion, offal, or detritus [II-IV]; x = major food in diet, o = minor food, * =
incidental food, ? = probable food.)
Habitat, bird trophic levels
(I-IV. Sc), and food categories
Inshore neritic
Oceanic and offshore neritic Inshore neritic
II III IV Sc I II III IV Sc
F F
i i
s C s C
h a h a
/ r C / r
s r r C s r
q i u r q i
u o s u u o
i n t s i n
d / a t d /
o c a F o
e f e c iF e f
Cg f a eC s i g f
og a n ao hs g a
C Pe s C l , neE , hC s l
r ol e / , l c , e /
u l e& p d m eh m p & d
s yn h e i bn i M i bh e
t ct l a t d e t n o dea l t
a he a l B r P w n e o l wn l B a r
c a r r Fo i i l a t rd l a to i r i
e eav ip r t a t h a e u t hp r v t
a t t aso d un e i t r s e i od a u
Seabirds n e e e hd s s t r c em c r cd s e s
Gavia immer * xx
G. adamsii * ox
G. stellata * ox

Podiceps grisegena o xo
Diomedea nigripes x oo oxx x
Fulmarus glacialis x ox oxx x
Puffinus griseus x xx o
P. tenuirostris x ox o
Pterodroma
x x
inexpectata
Oceanodroma furcata x oo xxx x
Phalacrocorax auritus o xo
P. pelagicus x x
P. urile x x
Philacte canagica x
Clangula hyemalis o x o
Histrionicus
x x o
histrionicus
Polysticta stelleri o x o o
Somateria mollissima x ox
S. spectabilis o ox
S. fischeri x x
Melanitta deglandi x o
M. perspicillata o x o
M. nigra o o x
Mergus serrator o xx
Haliaeetus
x x x
leucocephalus
Falco peregrinus x
Phalaropus fulicarius x x o x x
Lobipes lobatus x x o x x
Stercorarius spp. o xx ? x x x x
Larus hyperboreus o ooo o ooo o ox x x
L. glaucescens o ooo o ooo o ox x x
L. argentatus o ooo o ooo o ox o x
L. canus xoo o x x
Rissa tridactyla x xx o
R. brevirostris x xx o
Sterna paradisaea x xoo x o
S. aleutica x o
Uria aalge x o xx o o xo
U. lomvia x o xx o x ox
Lunda cirrhata ? xx
Fratercula
* xx
corniculata
Cepphus columba o xo
Brachyramphus
x ox
marmoratus
B. brevirostris x o
Synthliboramphus
x x x
antiquus
Cyclorrhynchus
x o **
psittaculus
Aethia cristatella x x
A. pusilla x o

A. pygmaea x

Table 14. Use of food resources by seabirds in the oceanic habitat, central subarctic domain. Information is
from Tables 1-10. (Trophic level I = plants, II = secondary carnivore, III = tertiary carnivore, IV = upper
level carnivore, Sc = scavenger on carrion, offal, or detritus [II-IV]; x = major food in diet, o = minor
food, * = incidental food, ? = probable food.)
Bird
trophic
levels and
food
categories
II III IV Sc
Fish/squid
eggs &
Seabirds Crustacean Polychaete Coelenterate larvae Fish Cephalopod Birds Carrion/offal/detritus
Diomedea
x o o o x x x
nigripes
D. immutabilis x
Fulmarus
x o x o x x x
glacialis
Puffinus
o x x
carneipes
P. griseus x x x
P. tenuirostris x o x
Pterodroma
x x
inexpectata
Oceanodroma
x o o o x x x
furcata
O. leucorhoa x o o o x x x
Phalaropus
x x o
fulicarius
Lobipes lobatus x x o
Stercorarius spp. o x x ? x
Larus
x o o o x x ? x
hyperboreus
L. glaucescens x o o o x x ? x
L. argentatus x o o o x x x
Rissa tridactyla x x x o
Xema sabini x x o o
Sterna
x x o o
paradisaea
Uria aalge x * x x
U. lomvia x * x x
Lunda cirrhata o x x
Fratercula
* x x
corniculata
Cerorhinca
x x
monocerata
Synthliboramphus
x x
antiquus
Cyclorrhynchus
x o * *
psittaculus

Ptychoramphus
x o
aleuticus
Most species (roughly 53% in any community) include two or three prey categories in their diets—usually
midwater schooling fish, squid, and crustaceans. These birds include the most numerous in the communities—the
shearwaters and some alcids—which feed largely on three prey types, and also include some of the less abundant
birds, the marine ducks, which feed mostly on two prey categories.
The remaining seabirds are more general in their feeding. Many have large populations, but are not as abundant as
shearwaters or most alcids. The true "generalists" are the species that feed on as many as eight or more types of
prey, and relatively few (12%) such species exist in each avian community. These birds, the scavengers, include
black-footed albatross, fulmar, storm-petrels, and large gulls. The petrels are the scavengers of the oceanic habitat
and the gulls are their counterparts in the neritic habitat (but see Sanger 1973).
Another comparison is shown in Table 17, where the species in each community are categorized according to the
number feeding at each trophic level. If a species feeds at more than one level, it is tallied once in each level. Most
seabirds (66-77%) feed at the second and third levels as secondary and tertiary carnivores. Few feed as terminal
carnivores, and relatively few are scavengers. Actually, most scavenging occurs at levels II and III, so about 90%
of the seabirds in each community feed at levels II and III. Communities including an inshore neritic feeding
element are the only ones that include herbivores, and even then, few of these species exist in significant numbers
in the marine environment (discounting estuaries and sheltered bays).

Table 15. Use of food resources by seabirds in the North American coastal domain. Information is from Tables
1-10. (Trophic level I = plants, II = secondary carnivore, III = tertiary carnivore, IV = upper level
carnivore, Sc = scavenger on carrion, offal, or detritus [II-IV]; x = major food in diet, o = minor food, *
= incidental food, ? = probable food.)
Habitat, bird trophic levels (I-IV,
Sc), and food categories
Inshore
Oceanic and offshore neritic neritic
II III IV Sc I II III IV Sc
F F
i i
s C s C
h a h a
- r C / r
s r r C s r
q i u r q i
u o s u u o
i n t s i n
d / a t d /
o c a F o
e f e c e iF f
Cg f a eC g s i f
og a n ao g hs a
C Pe s C l , n e E s , hC l
r ol e / , l c , e /
u l e& p d m e h &m p d
s yn h e i bn i M i bh e
t ct l a t d e t n o l dea t
a he a l B r P w n e o l a wn l B r
c a r r Fo i i l a t rd l r a to i i
e eav ip r t a t h a e u v t hp r t
a t t aso d un e i t r s a e io d u
Seabirds n e e e hd s s t r c em c e r cd s s
Gavia immer * xx

G. adamsii * ox
G. arctica ox
G. stellata ox
Podiceps grisegena o xo
P. nigricollis x o
P. auritus x x o
Aechmophorus
o xx
occidentalis
Diomedea nigripes x oo oxx x
Fulmarus glacialis x ox oxx x
Puffinus creatopus o xx
P. carneipes o xx
P. bulleri x xx
P. griseus x xx o oo
P. tenuirostris x ox o oo
Oceanodroma furcata x oo oxx x
Pelecanus occidentalis x
Phalacrocorax auritus o xo
P. penicillatus ox
P. pelagicus x x
Branta bernicla x
Clangula hyemalis o x o o
Histrionicus
o x o
histrionicus
Melanitta deglandi x o o
M. perspicillata o x o
M. nigra * o o x
Mergus serrator * xx
Haliaeetus
x x x
leucocephalus
Falco peregrinus x
Phalaropus fulicarius x x o x x o
Lobipes lobatus x x o x x o
Stercorarius spp. o xx ? x xx o x
Larus hyperboreus o ooo ? o ooo o o x x x
L. glaucescens o ooo ? o ooo o x x x x
L. occidentalis x xxx o x ooo * * x x o x
L. argentatus o ooo o x ooo o o x o x
L. heermanni x x x
L. canus xoo o x x x
L. philadelphia x x o
Rissa tridactyla x xx o
Xema sabini x xoo
Sterna paradisaea x xoo
S. hirundo o x
Uria aalge x o xx o xo
U. lomvia x o xx o x ox
Lunda cirrhata ? xx
Fratercula corniculata * xx
Cerorhinca
x x
monocerata
Cepphus columba o xo

Table 16. Number of seabirds of different oceanographic regions having
different numbers of categories of food in their diets.
Number
of
categories
in the
[36]
Oceanographic diets
region (domain) 1 2 3 4 5-7 7 8+
Bering Sea
3 11 9 6 5 4 5
coastal
Bering Sea 2 6 5 7 0 5 0
Alaskan Stream 3 14 14 5 4 4 5
Central Subarctic 1 6 8 4 0 7 0
North American
3 14 17 6 3 4 6
Coastal
Total 12 51 53 28 12 24 16
Percent total
6 26 27 14 6 12 8
species (196)

It is readily apparent from the foregoing comparisons that much overlap
exists in the prey eaten by seabirds within each community. The question
whether real competition ever exists is academic. Competition perhaps
exists only rarely because seabirds partition resources through use of
different feeding methods, selection of different-sized prey, and habitat
zonation. Table 18 lists feeding methods (after Ashmole 1971 and Ainley
1977) and the body size and bill length of each species considered in this
review. Bill length is usually related directly to body size (Ashmole 1968;
Bédard 1969b), but note, for instance, that the longer species of the two
kittiwakes has the shorter bill. Body weight would be a better measure of
relative size than body size, but few reliable weight data are available for
seabirds.
The use of different feeding methods by species in each community grossly
assigns birds to feeding at different depths. Thus, whereas shearwaters,
puffins, and small gulls (Xema sp., Rissa spp.) overlap almost entirely in

prey categories and even prey species, the gulls can capture these organisms
only at the surface; the shearwaters capture them at shallow depths; and the
puffins capture them at much deeper depths. Direct field observations of
this phenomenon are few but Gould (1971) and Sealy (1973a) compared the
diets of birds feeding in mixed-species flocks. An example of how even
finer divergence in feeding methods helps to partition food resources has
been provided by Spring (1971) in his comparison of the two murres. Both
species feed by diving to great depths, but the thick-billed murre is able to
hover over the bottom and thereby is better able to capture benthic
organisms.

Table 17. Number of species feeding at different trophic levels within
seabird communities and habitats of the northeastern North Pacific
Ocean and Bering Sea. A single species can be represented in more
than one level. (Trophic level I = vegetarian, II = secondary
carnivore, III = tertiary carnivore, IV = upper level carnivore, Sc =
scavenger [II-IV].)
Inshore
Oceanic/offshore neritic neritic
Domain II III IV Sc I II III IV Sc
Bering
Sea 11 17 1? 10 6 23 18 6 6
Coastal
Bering
22 21 3? 11 — — — — —
Sea
Alaska
21 19 1? 12 5 28 21 6 6
Stream
Central
23 22 3? 12 — — — — —
Subarctic
North
American 25 24 3? 11 3 28 35 7 10
Coastal
Total 102 103 11? 56 14 79 74 19 22
Proportion 0.38 0.39 0.02[37] 0.21 0.07 0.38 0.28 0.09 0.10

Table 18. Size relationships and feeding methods of major species in the
eastern North Pacific and Bering Sea. (D = dive, SS = surface seize,
PP = pursuit plunge, Di = dip, P = plunge, T = tip, x = eats
seabirds, A = piracy, SP = shallow plunge.)
Body length[38] Bill length[39] Feeding[40]
Species (cm) (mm) method
Gavia adamsii 63.5 90-91 D
G. immer 61.0 80-82 D
G. arctica 45.7 51-52 D
G. stellata 43.5 51-52 D
Podiceps grisegena 33.0 48-50 D
P. nigricollis 22.9 24-26 D
P. auritus 24.1 23-24 D
Aechmophorus
45.7 65-76 D
occidentalis
Diomedea nigripes 71.1 141-144 SS
D. immutabilis 71.1 102-112 SS
Fulmarus glacialis 45.7 36-37 SS
Puffinus carneipes 45.7 41-46 PP
P. creatopus 45.7 41-46 PP
P. bulleri 38.1 38-45 PP
P. griseus 40.3 41-42 PP
P. tenuirostris 38.1 31-32 PP
Oceanodroma furcata 19.0 15 Di,SS
O. leucorhoa 19.0 16 Di,SS
Pterodroma inexpectata 29.2 26-27 SS
Phalacrocorax auritus 68.6 55-57 D
P. penicillatus 73.7 66-71 D
P. urile 71.1 54-55 D
P. pelagicus 55.9 47-50 D
Pelecanus occidentalis 104.0 294-319 P
Branta spp. (bernicla) 43.5 33-36 T
Philacte canagica 45.7 37-42 T
Anas spp. 40.0 32-35 T

Body length[38] Bill length[39] Feeding[40]
Species (cm) (mm) method
Clangula hyemalis 38.1 25-27 D
Histrionicus
30.5 25-28 D
histrionicus
Polysticta stelleri 30.5 37-43 D
Somateria mollisima 43.5 45-55 D
S. spectabilis 40.3 31-33 D
S. fischeri 38.1 22-26 D
Melanitta deglandi 35.6 41-44 D
M. perspicillata 40.3 ca. 40 D
M. nigra 35.6 42-47 D
Mergus serrator 40.3 45-54 D
Haliaeetus
80.0 52-54 X
leucocephalus
Falco peregrinus 37.5 21-25 X
Phalaropus fulicarius 16.5 22 SS
Lobipes lobatus 15.2 22 SS
Stercorarius pomarinus 43.5 40 SS,A
S. parasiticus 40.3 32 SS,A
S. longicaudus 38.1 29 SS,A
Larus hyperboreus 61.0 55-60 SS
L. glaucescens 55.9 54-58 SS
L. occidentalis 53.0 54-57 SS,Di
L. argentatus 50.8 48-54 SS,Di
L. californicus 43.5 45-50 SS,Di
L. heermanni 38.1 42-46 SS,Di
L. canus 35.6 34-36 SS,Di
L. philadelphia 27.9 30-31 Di
Rissa tridactyla 34.2 39-40 Di
R. brevirostris 38.1 29-30 Di
Xema sabini 27.9 26-27 Di
Sterna paradisaea 38.1 31-33 Di,SP
S. hirundo/forsteri 35.6 36-39 Di,SP

Body length[38] Bill length[39] Feeding[40]
Species (cm) (mm) method
S. aleutica 33.0 33 Di,SP
Uria aalge 35.6 43-47 D
U. lomvia 35.6 39-42 D
Lunda cirrhata 31.8 57-60 D
Fratercula corniculata 29.2 49-51 D
Cerorhinca monocerata 29.2 34-35 D
Cepphus columba 26.7 32-33 D
Brachyramphus
20.3 15 D
marmoratus
B. brevirostris 19.0 10 D
Synthliboramphus
20.3 13 D
antiquus
Ptychoramphus
17.8 19 D
aleuticus
Aethia pygmaea 16.5 8-9 D
A. pusilla 13.3 8 D
A. cristatella 17.8 11 D
Cyclorrhynchus
18.4 15 D
psittaculus
The scavengers (generalists) offer a good example of how a range of bird
and bill sizes is usually represented among species having similar diets and
feeding methods. The progression of oceanic scavenger sizes is graded
rather evenly from the black-footed albatross down to the northern fulmar,
to the scaled petrel, to the storm-petrel. All these species capture prey that
occur only at or near the water surface. Recently Sanger (1973) reported
appreciable numbers of glaucous-winged gulls (Larus glaucescens) and
herring gulls (L. argentatus), noted neritic scavengers, out in the oceanic
realm of the petrel. He presented limited data that suggested an overlap
between the diet of these gulls and that of black-footed albatrosses, as noted
by Miller (1940). It would not be surprising if these gulls were as much
generalists in the oceanic habitat as they are in the neritic. Interestingly,
their bill and body sizes fall between those of the albatross and the fulmar,
thus in theory enabling them to invade the oceanic habitat without great

competition. It is likely that their invasion occurred during historical times
and is related to their habit of following fishing boats from shore out to sea
(Sanger 1973). If so, the gulls might be assuming from other species part of
a previously uncontested resource.
Another interesting group of species that shows close similarities in diet
consists of the piscivorous loons, grebes, and mergansers. All these birds,
including seven or eight species, apparently feed on fish occurring on or
near the bottom in the inshore neritic habitat. Again, however, an even
progression in size exists: yellow-billed loon (Gavia adamsii), common
loon (G. immer), arctic loon (G. arctica), red-throated loon (G. stellata),
western grebe (Aechmophorus occidentalis), red-necked grebe (Podiceps
grisegena), and common merganser (Mergus merganser). Most likely then,
they select different-sized fish. Another example of this phenomenon is
provided by the eight neritic gulls, which are largely scavengers and show a
remarkably even progression in bill and body size. Finally, as shown clearly
by Bédard (1969a, 1969b) and Harris (1970), alcids of different sizes select
different-sized prey, often of the same species.
A final important way in which seabirds partition available resources is by
inhabiting different zones. Zonation is especially evident during the
breeding season when species common to the same breeding site sort
themselves out according to the distances they range for food. This
phenomenon was discussed by Murphy (1936), Shuntov (1974), Sealy
(1972), Cody (1973), and Scott (1973).

Trophic Relations and Seabird Conservation

The species that appear to have specialized food habits (if further research
confirms that indeed they do) are probably very sensitive to vagaries in
food availability or are, at least, much more sensitive than other species.
Some specialists which also have very restricted distributions would,
therefore, be susceptible to localized catastrophes occurring where
specialists are concentrated around the food resource. This is proved in the
case of the scoters, which are both specialized and rather restricted to
nearshore beds of molluscs and have fallen victim to local oil slicks (Smail
et al. 1972). An example of another potentially critical situation is that of
the black brant, which at certain times of the year concentrate their entire

population around eelgrass beds in Bristol Bay, Alaska, where much
offshore oil drilling may soon occur.
Birds adapted to feed by diving, with the exception of cormorants, spend
most of their time in the water. These species are therefore most susceptible
to oiling (Smail et al. 1972), but pursuit plungers (the shearwaters) are also
highly susceptible (Point Reyes Bird Observatory, unpublished data). A
characteristic of polar and subpolar seabird communities is the high
percentage of birds that feed by diving and pursuit plunging. These birds
are mostly absent from tropical and subtropical communities because
feeding by these methods is not adaptive there (Ainley 1977). Hence, oil
pollution has all the potential of rendering maladaptive the principal feeding
methods of many polar seabirds.
Another way in which seabird feeding relates to conservation problems
concerns competition between birds and man for commercially valuable
fishes. A related problem is the mass mortality of seabirds due to man's
fishing gear. An acute situation is the drowning of seabirds caught in
salmon gill nets (Bartonek et al. 1974; Pacific Seabird Group 1975; Ripley
1975; King et al., this volume). Immediate action is definitely required.
Further, competition between birds and man for the same resource has the
potential for disastrous effects on bird populations if humans out-compete
the birds and overfish the resource. A classic example, reviewed by Idyll
(1973), is the possible collapse of the Peruvian anchovy (Engraulis ringens)
fishery; if overfishing and an El Niño should coincide, the Peruvian seabird
populations could collapse as well. The California fisheries and apparently
the double-crested cormorants that nest on the Farallon Islands have both
suffered from the demise of the Pacific sardine (Sardinops caerulea) in the
California current (Ainley and Lewis 1974). In regulating fish harvests,
fishery organizations should include in their calculations the harvest by
creatures other than man (Schaefer 1970), rather than evading the issue by
referring to a vague "natural mortality."

Finally, fishing by humans can benefit seabirds by removing fish (or
whales) that compete with birds for food (Laws 1977). A potential example

is that of northern California, where salmon and seabirds both feed heavily
on juvenile rockfishes (Fitch and Lavenberg 1971; Point Reyes Bird
Observatory, unpublished data). Harvest of salmon should theoretically
leave more rockfish available for birds to eat. This sort of situation has not
yet been fully documented and definitely warrants further study, especially
in such areas as the Bering Sea, where some fish stocks have become
depressed due to overfishing (Gulland 1970).

Recommendations for Further Research

Many people realize intuitively that seabirds are important members of
marine ecosystems. Although the supporting evidence is not now available,
it will be needed if seabirds are to be protected. Emotion alone will not
justify the protection of seabirds in an age when the human race moves
steadily toward global famine. The job at hand is, in part, to sell seabirds,
not just to the public, government officials, executives of oil companies, or
fish-packing concerns, but also to marine biologists and oceanographers, for
the scientists have the best means to study organisms at sea. We must move
away from the concept that seabirds are merely yo-yos of various sizes,
shapes, and colors on strings of various lengths that venture forth to sea
from the land, grab a quick lunch, and then return to the safety of terra
firma. Seabirds are marine organisms and deserve at least as much research
attention as that currently given marine mammals.
The information now available on seabird diets is largely presented in terms
of the number and volume of various prey species taken. Whereas these
data provide the relative importance of prey, fishery data on prey stocks are
usually measured in terms of biomass. Thus, it is difficult to relate seabird
data to the immense wealth of information on biological oceanography. If
we are to recognize the importance of seabirds in the nutrient and energy
cycling of marine ecosystems, rather than considering them merely as "yo-
yo predators," we must relate them to the total marine community.
The goal of marine ornithologists should be to refine and broaden
considerably in detail such studies as those by Sanger (1972), Shuntov
(1974), and Laws (1977), who attempted to assess the relations between
seabird populations and stocks of other marine organisms for the northern
North Pacific, the world oceans, and the Antarctic, respectively. The trophic

roles played by seabirds must be studied in detail at the community level
year-round before those analyses can be properly refined. Another
exemplary work is that done by Brownell (1974), who studied trophic
relations of higher vertebrates off Uruguay, including dolphins, pinnipeds,
seabirds, and some large fish. In a review study, Sanger (1974) considered
the food-chain relations of similar vertebrates in the Bering Sea. These sorts
of studies will serve to bring the role of seabirds into perspective with other
upper trophic level feeders.

Acknowledgments

We much appreciate the opportunity to participate in the symposium at
which this paper was presented. The encouragement and help given by J. C.
Bartonek was indispensable. D. G. Ainley's participation in the symposium
was supported by the Point Reyes Bird Observatory. This is contribution
No. 124 of the Point Reyes Bird Observatory.

References

Ainley, D. G. 1977. Feeding methods of seabirds: a comparison
of polar and tropical communities. Pages 669-685 in G. A.
Llano, ed. Adaptations in Antarctic ecosystems. Gulf
Publishing Co., Houston, Texas.
Ainley, D. G., and T. J. Lewis. 1974. The history of Farallon
Island marine bird populations, 1854-1972. Condor 76:432-
446.
Ashmole, N. P. 1968. Body size, prey size and ecological
segregation in five sympatric tropical terns (Ayes; Laridae).
Syst. Zool. 17:292-304.
Ashmole, N. P. 1971. Sea bird ecology and the marine
environment. Pages 223-286 in D. S. Farner and J. R. King,
eds. Avian Biology, Vol. 1. Academic Press, N. Y.
Ashmole, N. P., and M. J. Ashmole. 1967. Comparative feeding
ecology of sea birds of a tropical oceanic island. Peabody
Mus. Nat. Hist., Yale Univ., Bull. 24:1-131.

Bailey, A. 1922. Notes on the yellow-billed loon. Condor 24:204-
205.
Bailey, A. 1927. Notes on the birds of southeastern Alaska. Auk
44:1-23.
Banner, A. H. 1954. New records of Mysidacea and Euphausiacea
from the northeastern Pacific and adjacent areas. Pac. Sci.
8:125-139.
Bartonek, J. C., R. Elsner, and F. H. Fay. 1974. Mammals and
birds. Pages 23-28 in E. J. Kelly and D. W. Hood, eds.
Probes: a prospectus on processes and resources of the
Bearing Sea shelf. Inst. Mar. Sci., Univ. Alaska, Fairbanks,
Publ. Inf. Bull. 74-1.
Bartonek, J. C., and D. D. Gibson. 1972. Summer distribution of
pelagic birds in Bristol Bay, Alaska. Condor 74:416-422.
Bartsch, P. 1922. A visit to Midway Island. Auk 39:481-488.
Bédard, J. 1969a. Feeding of the least, crested, and parakeet
auklets around St. Lawrence Island, Alaska. Can. J. Zool.
47:1025-1050.
Bédard, J. 1969b. Adaptive radiation in Alcidae. Ibis 111:189-
198.
Belopol'skii, L. O. 1961. Ecology of sea colony birds of the
Barents Sea. (Transl. from Russian.) Israel Program for
Scientific Translations, Jerusalem. 346 pp.
Bent, A. C. 1921. Life histories of North American gulls and
terns. U.S. Natl. Mus. Bull. 113. 345 pp.
Bent, A. C. 1922. Life histories of North American petrels and
pelicans and their allies. U.S. Natl. Mus. Bull. 121. 343 pp.
Bent, A. C. 1925. Life histories of North American wild fowl.
U.S. Natl. Mus. Bull. 130. 311 pp.
Bent, A. C. 1946. Life histories of North American diving birds.
(Reprint of U.S. Natl. Mus. Bull. 107.) Dodd, Mead and Co.,
N. Y. 237 pp.

Brownell, R. L., Jr. 1974. Feeding ecology of the Franciscana
Dolphin, Pontoporia blainvillei, and associated top trophic
vertebrates in Uruguayan waters. Ph.D. Thesis. Univ. Tokyo,
Tokyo, Japan.
Chatwin, S. L. 1956. The western grebe taken on hook and line.
Condor 58:73-74.
Cleaver, F. C., and D. M. Franett. 1945. The predation by
seabirds upon the eggs of the Pacific herring (Clupea
pallasii) at Holmes Harbor during 1945. State of
Washington, Department of Fisheries, Biological Report
46B. 18 pp.
Cody, M. L. 1973. Coexistence, coevolution and convergent
evolution in seabird communities. Ecology 54:31-44.
Cottam, C. 1939. Food habits of North American diving ducks.
U.S. Dep. Agric., Tech. Bull. 643. 140 pp.
Cottam, C., and P. Knappen. 1939. Food of some uncommon
North American birds. Auk 56:138-169.
Craddock, D. R., and R. D. Carlson. 1970. Peregrine falcon
observed feeding far at sea. Condor 72:375-376.
Dement'ev, G. P., R. N. Meklenburtsev, A. M. Sudilovskaya, and
E. P. Sangenberg. 1968. Birds of the Soviet Union. Vol. 2.
(Transl. from Russian.) Israel Program for Scientific
Translations, Jerusalem. 553 pp.
Divoky, G. J. 1976. The pelagic feeding habits of the Ivory and
Ross' gulls. Condor 78:85-90.
Dodimead, A. J., F. Favorite, and T. Hirano. 1963. Review of
oceanography of the subarctic Pacific region. Int. North Pac.
Fish. Comm. Bull. 13. 195 pp.
Drent, R. H. 1965. Breeding biology of the pigeon guillemot,
Cepphus columba. Ardea 53:99-160.
Dunbar, M. J. 1946. On Themisto libellula in Baffin Island
coastal waters. J. Fish. Res. Board Can. 6:419-434.

Einarrson, H. 1945. Euphausiacea. I. North Atlantic species.
Dana-Rep. Carlsberg Found. 27. 185 pp.
Falla, R. A. 1934. The distribution and breeding habits of petrels
in northern New Zealand. Rec. Aukl. Inst. Mus. I:245-260.
Favorite, F., A. J. Dodimead, and K. Nasu. 1976. Oceanography
of the subarctic Pacific region, 1960-71. Int. North Pac.
Fish. Comm. Bull. 33:1-187.
Fay, F. H., and T. J. Cade. 1959. An ecological analysis of the
avifauna of St. Lawrence Island, Alaska. Univ. Calif. Publ.
Zool. 63:73-150.
Fisher, J. 1952. The fulmar. Collins, London. 496 pp.
Fisher, W. K. 1904. On the habits of the Laysan albatross. Auk
21:8-19.
Fitch, J. E., and R. J. Lavenberg. 1971. Marine food and game
fishes of California. Univ. Calif. Press, Berkeley. 179 pp.
Follett, W. I., and D. G. Ainley. 1976. Fishes collected by pigeon
guillemots, Cepphus columba Pallas, nesting on Southeast
Farallon Island, California. Calif. Fish Game 62:28-31.
Friedmann, H. 1950. Birds of North and middle America. Part XI.
U.S. Natl. Mus. Bull. 50. 793 pp.
Gabrielson, I. N., and S. G. Jewett. 1940. Birds of Oregon.
Oregon State College, Corvallis. 650 pp.
Gabrielson, I. N., and F. C. Lincoln. 1959. Birds of Alaska.
Stackpole Co., Harrisburg, Pennsylvania. 922 pp.
Gould, P. J. 1971. Interactions of seabirds over the open ocean.
Ph.D. Thesis. Univ. of Arizona, Tucson. 110 pp.
Grinnell, J. 1897. Notes on the marbled murrelet. Osprey 1:115-
117.
Grinnell, J. 1899. The rhinoceros auklet at Catalina Island. Bull.
Cooper Ornithol. Club 1:87-88.

Gulland, J. A. 1970. The fish resources of the ocean. FAO, Rome.
255 pp.
Hamilton, W. J. 1958. Pelagic birds observed on a north Pacific
crossing. Condor 60:159-164.
Harris, M. P. 1965. The food of some Larus gulls. Ibis 107:43-53.
Harris, M. P. 1970. Differences in the diet of British auks. Ibis
112:540-541.
Hart, J. L. 1973. Pacific fishes of Canada. Fish. Res. Board Can.
Bull. 180. 740 pp.
Hartley, C. H., and J. Fisher. 1936. The marine foods of birds in
an inland fjord region of West Spitsbergen. Part 2. Birds. J.
Anim. Ecol. 5:370-389.
Heath, H. 1915. Birds observed on Forrester Island, Alaska,
during the summer of 1913. Condor 17:20-41.
Hubbs, C. L., A. L. Kelly, and C. Limbaugh. 1970. Diversity in
feeding by Brandt's cormorant near San Diego. Calif. Fish
Game 53:156-165.
Idyll, C. P. 1973. The anchovy crisis. Sci. Am. 228:22-29.
Imber, M. J. 1973. The food of grey-faced petrels (Pterodroma
macroptera gouldi Hutton), with special reference to diurnal
migration of their prey. J. Anim. Ecol. 42:645-662.
Ingolfsson, A. 1967. The feeding ecology of five species of large
gulls (Larus) in Iceland. Ph.D. Thesis. Univ. of Michigan,
Ann Arbor. 186 pp.
Jewett, S. G., W. P. Taylor, W. T. Shaw, and J. W. Aldrich. 1953.
Birds of Washington State. Univ. of Washington Press,
Seattle. 767 pp.
Koelink, A. F. 1972. Bioenergetics of growth in the pigeon
guillemot, Cepphus columba. M. S. Thesis. Univ. of British
Columbia, Vancouver, Canada. 71 pp.

Komaki, Y. 1967. On the surface swarming of euphausiid
crustaceans. Pac. Sci. 21:433-448.
Kooyman, G. L. 1974. Behaviour and physiology of diving.
Pages 115-138 in B. Stonehouse, ed. The biology of
penguins. Macmillan, London.
Kortright, F. H. 1942. The ducks, geese and swans of North
America. Wildlife Management Institute, Washington, D.C.,
and Stackpole Co., Harrisburg, Pennsylvania. 476 pp.
Kozlova, E. V. 1961. Fauna of the U.S.S.R., Birds: Alcae. (Transl.
from Russian.) Israel Program for Scientific Translations,
Jerusalem. 140 pp.
Kuroda, N. 1954. On the classification and phylogeny of the
order Tubinares, particularly the shearwaters (Puffinus).
Herald Co., Tokyo. 179 pp.
Kuroda, N. 1955. Observations on pelagic birds of the Northwest
Pacific. Condor 57:290-300.
Laws, R. M. 1977. The significance of vertebrates in the
Antarctic marine ecosystem. Pages 411-438 in G. A. Llano,
ed. Adaptations in Antarctic ecosystems. Gulf Publishing
Co., Houston, Texas.
Linton, C. B. 1908. Notes from Santa Cruz Island. Condor
10:124.
Mabbot, D.C. 1920. Food habits of seven species of American
shoal-water ducks. U.S. Dep. Agric., Bull. 862. 68 pp.
Madsen, F. J. 1957. On the food habits of some fish-eating birds
in Denmark. Dan. Rev. Game Biol. 3(2):19-83.
Manuwal, D. A. 1974. The natural history of Cassin's auklet
(Ptychoramphus aleuticus). Condor 76:421-431.
Martin, P. W. 1942. Notes on some pelagic birds off the coast of
British Columbia. Condor 44:27-29.
Martin, P. W., and M. T. Myers. 1969. Observations on the
distribution and migration of some seabirds off the outer

coasts of British Columbia and Washington State, 1946-
1949. Syesis 2:241-256.
McGilvrey, E. B. 1967. Food habits of sea ducks from the
northeastern United States. Pages 142-145 in Wildfowl Trust
18th annual report.
Miller, L. 1936. Some maritime birds observed off San Diego,
California. Condor 38:9-16.
Miller, L. 1940. Observations on the black-footed albatross.
Condor 42:229-238.
Munro, J. A. 1941. Studies of waterfowl in British Columbia: the
grebes. B. C. Prov. Mus. Occas. Pap. 3. 71 pp.
Munro, J. A., and W. A. Clemens. 1931. Waterfowl in relation to
the spawning of herring in British Columbia. Biol. Board
Can. Bull. 17. 46 pp.
Munro, J. A., and W. A. Clemens. 1939. The food and feeding
habits of the red-breasted merganser in British Columbia. J.
Wildl. Manage. 3:46-53.
Murphy, R. C. 1936. Oceanic birds of South America, Vol. 2.
Macmillan, N. Y. 604 pp.
Ogi, H., and T. Tsujita. 1973. Preliminary examination of
stomach contents of murres (Uria spp.) from the eastern
Bering Sea and Bristol Bay, June-August, 1970 and 1971.
Jpn. J. Ecol. 23:201-209.
Oliver, W. R. B. 1955. New Zealand birds, 2nd ed. A. H. and A.
W. Reed, Wellington, New Zealand.
Pacific Seabird Group. 1975. Policy statement: Incidental seabird
kills from salmon gillnet fisheries. Pac. Seabird Group Bull.
2:19-20.
Palmer, R. S. 1962. Handbook of North American birds. Vol. 1.
Yale Univ. Press, New Haven, Connecticut.
Pearson, T. H. 1968. The feeding biology of sea bird species
breeding on the Farne Islands, Northumberland. J. Anim.

Ecol. 37:521-551.
Perthon, P. 1968. Food and feeding habits of the common eider
(Somateria mollissima). Nytt. Mag. Zool. 15:97-111.
Phillips, R. E., and G. D. Carter. 1957. Winter food of western
grebes. Murrelet 38:5-6.
Preble, E. A., and W. L. McAtee. 1923. A biological survey of the
Pribilof Islands, Alaska. U.S. Bur. Biol. Surv. N. Am. Fauna
46. 255 pp.
Richardson, F. 1961. Breeding biology of the rhinoceros auklet
on Protection Island, Washington. Condor 63:456-473.
Ripley, S. D. 1975. The view from the castle. Smithsonian 6:6.
Robbins, C. S., B. Brunn, and H. S. Zim. 1966. Birds of North
America. Golden Press, N. Y. 340 pp.
Roberts, A. A., and E. H. Huntington. 1959. Food habits of the
merganser in New Mexico. N. M. Dep. Fish Game, Bull. 9.
36 pp.
Robertson, I. 1974. The food of nesting double-crested and
pelagic cormorants at Mandarte Island, British Columbia,
with notes on feeding ecology. Condor 76:346-348.
Robertson, I. 1972. Studies on fish-eating birds and their
influence on stocks of the Pacific herring, Clupea harengus,
in the Gulf Islands of British Columbia. Herring
Investigations, Pac. Biol. Stn., Naimo, B.C. 28 pp.
(Unpublished report)
Sanger, G. A. 1972. Preliminary standing stock and biomass
estimates of seabirds in the subarctic Pacific region. Pages
589-611 in A. Y. Takenouti et al., eds. Biological
oceanography of the northern north Pacific Ocean. Idemitsu
Shoten, Tokyo. 626 pp.
Sanger, G. A. 1973. Pelagic records of glaucous-winged and
herring gulls in the north Pacific Ocean. Auk 90:384-393.

Sanger, G. A. 1974. A preliminary look at marine mammal food-
chain relationships in Alaskan waters. U.S. Natl. Mar. Fish.
Serv., Mar. Mammal Div., Seattle. 29 pp. (Unpublished
report)
Schaefer, M. S. 1970. Men, birds and anchovies in the Peru
current—dynamic interactions. Trans. Am. Fish. Soc.
99:461-467.
Scott, J. M. 1973. Resource allocation in four synoptic species of
marine diving birds. Ph.D. Thesis. Oregon State Univ.,
Corvallis. 97 pp.
Scott, J. M., J. Butler, W. G. Pearcy, and G. A. Bertrand. 1971.
Occurrence of the Xantus' murrelet off the Oregon coast.
Condor 73:254.
Sealy, S. G. 1972. Adaptive differences in breeding biology in the
marine bird family Alcidae. Ph.D. Thesis. Univ. of
Michigan, Ann Arbor. 283 pp.
Sealy, S. G. 1973a. Interspecific feeding assemblages of marine
birds off British Columbia. Auk 90:796-802.
Sealy, S. G. 1973b. Breeding biology of the horned puffin on St.
Lawrence Island, Bering Sea, with zoogeographical notes on
the North Pacific puffins. Pac. Sci. 27:99-119.
Sealy, S. G. 1975. Feeding ecology of the ancient and marbled
murrelets near Langara Island, British Columbia. Can. J.
Zool. 53:418-433.
Serventy, D. L., V. Serventy, and J. Warham. 1971. The handbook
of Australian sea birds. A. H. and A. W. Reed, Wellington,
New Zealand. 254 pp.
Sheard, K. 1953. Taxonomy, distribution and development of the
Euphausiacea (Crustacea). Rep. B.A.N.Z. Antarct. Res.
Exped., Ser. B (Zoology and Botany), 8:1-72.
Shuntov, V. P. 1972. Sea birds and the biological structure of the
ocean. (Transl. from Russian.) Bur. Sport Fish. Wildl. and

Natl. Sci. Found., Washington, D.C. Nat. Tech. Inf. Serv. TT
7455032. 566 pp.
Smail, J., D. G. Ainley, and H. Strong. 1972. Notes on birds
killed in the 1971 San Francisco oil spill. Calif. Birds 3:25-
32.
Spaans, A. L. 1971. On the feeding ecology of the herring gull
Larus argentatus Pont. in the northern part of the
Netherlands. Ardea 59:73-188.
Spring, L. 1971. A comparison of functional and morphological
adaptations in the common murre (Uria aalge) and thick-
billed murre (Uria lomvia). Condor 73:1-27.
Stejneger, L. 1885. Results of ornithological explorations in the
Commander Islands and Kamchatka. U.S. Natl. Mus. Bull.
29:7-362.
Sverdrup, H. V., M. W. Johnson, and R. H. Fleming. 1942. The
oceans: their physics, chemistry and general biology.
Prentice-Hall, Englewood Cliffs, N. J. 1087 pp.
Swartz, L. G. 1966. Sea-cliff birds. Pages 611-678 in N. J.
Wilimovsky and J. N. Wolfe, eds. Environment of the Cape
Thompson region, Alaska. U.S. Atomic Energy
Commission, Div. Tech. Inf., Oak Ridge, Tennessee. 1250
pp.
Thoresen, A. C., and E. S. Booth. 1958. Breeding activities of the
pigeon guillemot, Cepphus columba columba (Pallas). Dep.
Biol. Sci., Walla Walla College, Washington, Publ. 23. 34
pp.
Tuck, L. M., and H. J. Squires. 1955. Food and feeding habits of
Brunnich's murre (Uria lomvia lomvia) on Akpatok Island. J.
Fish. Res. Board Can. 12:781-792.
Uspenski, S. M. 1958. The bird bazaars of Novaya Zemlya.
(Transl. from Russian.) Transl. by Department of Northern
Affairs and Natural Resources, Canada. 159 pp.

Ward, J. G. 1973. Reproductive success, food supply, and the
evolution of clutch-size in the glaucous-winged gull. Ph.D.
Thesis. Univ. of British Columbia, Vancouver, Canada. 119
pp.
Wetmore, A. 1924. Food and economic relations of North
American grebes. U.S. Dep. Agric., Bull. 1196. 23 pp.
White, C. M., W. B. Emison, and F. S. L. Williamson. 1971.
Dynamics of raptor predation on Amchitka Island, Alaska.
Bioscience 21:623-627.
White, C. M., W. B. Emison, and F. S. L. Williamson. 1973. DDE
in a resident Aleutian Island peregrine population. Condor
75:306-311.
Zelikman, E. A. 1961. The behavior pattern of the Barents Sea
Euphausiacea and possible causes of seasonal vertical
migrations. Int. Rev. Ges. Hydrobiol. Hydrogr. 46:276-281.

FOOTNOTES:

[15] Present address: U.S. Fish and Wildlife Service, Office of Biological
Services, 1011 East Tudor Road, Anchorage, Alaska 99503.
[16] Other incidental prey were squid and atherinid fishes, both at the Farallon
Islands.
[17] Other incidental prey were squid and such fishes as atherinids, Zaniolepis,
Genyonemus and Peprilus at the Farallones, and atherinids, Trachurus and
Heterostichus at San Diego.
[18] Other incidental prey were polychaetes at Netarts and the Farallon Islands.
[19] Principal sources: Bent 1925; Cleaver and Franett 1945; Cottam 1939;
Cottam and Knappen 1939; Kortright 1942; Mabbot 1920; McGilvrey 1967;
Munro and Clemens 1939; Roberts and Huntington 1959.
[20] Other incidental items were the fish Cololabis and Peprilus at the Farallon
Islands.
[21] Other incidental items were myctophid fish in northeastern Canada.
[22] Other incidental items included the lamprey (Lampetra) at the Farallon
Islands.
[23] Bent (1946) listed "fish" as prey.
[24] Grinnell (1897) listed "fish" as the major dietary component.
[25] Bédard (1969a) also listed "fish" as an incidental item.

[26] Other incidental prey were copepods and isopods.
[27] Other incidental prey were pholids in Denmark.
[28] Other incidental prey were copepods and cephalopods in North Atlantic
areas.
[29] Other incidental prey were isopods in western North America and fish eggs
near Vancouver Island.
[30] Other incidental prey were fish eggs in Denmark.
[31] Offal from wounded whales and seals, and bits of food, primarily
crustaceans and fish, from feeding whales are important scavenger foods (Bent
1922).
[32] Other incidental prey were isopods in the North Pacific.
[33] Other incidental prey were the fish Merluccius at the Farallon Islands.
[34] Other incidental prey were isopods near the Pribilofs and in the Chukchi
Sea, and amphipods in the latter area; Bent (1921) considered "crustaceans" to
be major prey.
[35] Study conducted during period of breeding failure.
[36] These are the "food categories" of Tables 11-15. Items included in diets are
not included here.
[37] Proportion based on the arbitrary assumption that half (5) of the 11 species
in question catch and eat birds at sea.
[38] Information on body sizes (length) is from Robbins et al. (1966).
[39] Information on bill lengths is from Palmer (1962), Dement'ev et al. (1968),
and Friedmann (1950).
[40] Feeding methods are from Ashmole (1971) as adapted by Ainley (unpubl.
manuscr.).

Population Dynamics in Northern Marine Birds

by
William H. Drury
College of the Atlantic
Bar Harbor, Maine 04609

Abstract

It seems only reasonable to assume that populations of
marine birds fluctuate even when not disturbed by man; such
fluctuations would result both from the secondary effects of
species adaptive tactics and from changes in the marine
environment. I briefly review some human activities and
some other natural processes that have resulted in changes in
numbers and distribution of seabirds and present a short
discussion of theoretical models which emphasizes that
conclusions drawn or predictions made from models of the
dynamics of populations depend upon the assumptions about
stability that were used in preparing the models. I then
review those special characteristics of seabirds which are
directly relevant to planning programs intended to protect
seabirds or encourage their increase and identify several
goals for improving our understanding of the population
dynamics and biology of marine birds. My general
conclusion is that enough is already known to undertake
effective conservation programs, and that time is pressing.
Seabirds have been categorized as renewable resources in only a few
places, although their symbolic value has been recognized for centuries (for
example, the medieval poem "The Seafarer" and the designs on Saint
Cuthbert's tunic). With the exception of the Russians (Belopol'skii 1961;
Uspenski 1956), the Australians (Serventy 1967), and the Icelanders,

industrialized peoples have not considered seabirds to be salable and
therefore worth managing. Yet during many centuries the seabirds of the
northern seas were a major food for coastal and island villages (Bent 1919,
1921, 1922; Fisher and Lockley 1954).
Some biological principles that affect the dynamics of seabird populations
are identified in this paper. I believe these principles must form the basis of
plans to maintain and increase seabird numbers.
I describe some observations of population changes, review briefly the
conflicting theoretical frameworks for population dynamics, and identify
some of the biological characteristics of marine birds that affect the way in
which population changes occur. The terms "seabirds" and "marine birds"
are used interchangeably for those bird species which depend upon salt
water for some part of their annual cycle (c.f., the Pacific Seabird Group).

Population Fluctuations

Broadly stated, the populations of northern seabirds have shown marked
short-and long-term fluctuations. Most authors have assumed that all such
fluctuations reflect human disturbance of the natural system, because of the
obvious effects of human predation during the last 200 years.

Human Impact

In the centuries before people traveled extensively between islands,
seabirds were taken in ways that we judge must have allowed the survival
of the colonies (e.g., those at the Faroes or Saint Kilda, those in Iceland and
Greenland, or those in the Aleutian Islands and the Bering Strait). We
presume either that the populations of island peoples were regulated by
shortage of resources other than seabirds or that those who overcropped and
eliminated the seabirds suffered the consequences.

Negative Effects

When a sea-going, commodity-oriented way of life evolved, seabirds were
killed in huge numbers for such uses as the plumage trade, fish bait, or
rendering into oil (Tuck 1960; Fisher and Lockley 1954). Even the

elimination of several colonies—e.g., Funk Island, Newfoundland (Tuck
1960); Seal Island, Eastern Egg Rock, Maine (Norton 1921); Muskeget,
Massachusetts (Forbush 1929)—may have had little effect on the rate of
cropping because those who killed off one source could probably seek out
another. As the colonial seabirds became scarce they became more valuable,
which stimulated more intensive pursuit of the remnants (Dutcher 1901,
1904).
In some places where seabird colonies did not supply a croppable economic
resource, the islands were used for alternative crops with at least temporary
commodity value (e.g., foxes were introduced in the Aleutian Islands; Bent
1919). Large herbivores were introduced to supply meat for island residents
(e.g., Saint Matthew Island; Klein 1959), as well as pigs, cattle, sheep,
goats, and rabbits on islands in the North Atlantic and southern oceans
(many authors). Increases in many seabird populations over the last 75
years have been generally associated with relief from predation by humans
such as the fowlers, eggers, and plume hunters of the 19th century. Such
relief may have been partly responsible for the increase of North Atlantic
gannets, Sula bassana, and common murres or guillemots, Uria aalge
(Fisher and Vevers 1943, 1944; Cramp et al. 1974). On a smaller scale,
several population increases along the coast of New England have been
recorded following the enactment of protective legislation (Dutcher 1901,
1904; Norton 1921, 1924; Palmer 1949; Drury 1973).
Coulson (1974) argued that in addition to relief from predation, the
explosion of the population of kittiwakes (Rissa tridactyla) in this century
resulted from access to previously un-occupiable breeding sites. Nesting
cliffs and buildings suitable for kittiwake nesting are abundant and now
protected from egging or fowling.

Positive Effects

There can be little doubt that human activities have also had marked
positive effects in some cases. For example, Fisher (1952) suggested that
the North Atlantic fulmar (Fulmarus glacialis) was provided food first by
whaling, then by commercial fishing, and that this food allowed the species
to increase steadily over the last 3 centuries.

The worldwide increase of gulls (Larus argentatus, L. fuscus, L.
dominicanus, L. ridibundus, L. novae-hollandii) has been credited to
availability of food from wasteful human garbage disposal (Murray and
Carrick 1964; Fordham 1968, 1970; Harris 1964; Harris and Plumb 1965;
Kadlec and Drury 1968; Brown 1967; Mills 1973; Vermeer 1963).
It is hard to dismiss the evidence pointing to the impact of human activities
on seabird populations during the last 3 centuries. Yet it would be
misleading to assume that without man's interference seabird populations
would have remained stable. Success in designing programs of protection
and population enhancement must allow for the realities—that seabird
populations fluctuate inherently, and that secular changes occur regularly in
their environment.

Impact of Natural Events

Some population changes appear to result from sudden impacts; other
changes are gradual.

Sudden Disasters

Gromme (1927) reported windrows of dead murres in the Unimak Pass and
Alaska Peninsula; die-offs of murres in winter storms in the Atlantic and
Arctic Oceans were reported by Tuck (1960) and Dement'ev et al. (1968).
Recently some mass mortalities have been associated with specific causes.
Bailey and Davenport (1972) reported that starvation caused the die-off of
common murres in the southern Bering Sea—Bristol Bay area. Foul
weather, which apparently inhibited feeding between 19 and 23 April 1970,
culminated in an intense storm. Similarly in late winter 1969 bad weather in
the Irish Sea, combined with strains of molt and perhaps contamination
with industrial chemicals, seems to have contributed to mass mortality of
the same species (called common guillemot in Britain; Holdgate 1971). The
seabird victims of this event had metabolized their body fat and as a result,
polychlorinated biphenyls (PCB) and other industrial chemicals passed into
livers, kidneys, and brains. Again, a storm at the end of a period of stress
seems to have been more than the birds could tolerate.

A further example of a die-off of waterfowl apparently brought on by
starvation was given by Barry (1968), who estimated that about 100,000
king eiders (Somateria spectabilis) died when they arrived before the ice
broke up in the Beaufort Sea in spring 1964.
Diseases have produced massive die-offs in marine birds. Fowl cholera
caused high mortality in nesting common eiders (Somateria mollissima) in
the Gulf of St. Lawrence in Quebec (Reed and Cousineau 1967) and in
Penobscot Bay, Maine, in the early 1960's (H. Mendall, personal
communication). Poisoning from a "red tide" (a bloom of the dinoflagellate
Gonyaulax tamerensis) caused a die-off of black ducks (Anas rubripes) and
herring gulls on the coast of New England in 1972. Similarly a die-off of
shags (Phalacrocorax aristotelis) on the east coast of England was caused
by a "red tide" (Coulson et al. 1968). During a period of 1 week 90% of the
shag nests on the Farne Islands in Northumberland were deserted and about
80% of the breeding population died.

Gradual Declines

When the new volcanic island of Bogoslov emerged in the western
Aleutians, Preble and McAtee (1923) reported that it was colonized by large
numbers of pigeon guillemots (Cepphus columba), but in the following
decades the guillemots have steadily decreased (G. J. Divoky, personal
communication). As a further example, the nesting population of Atlantic
puffins (Fratercula arctica) in the Atlantic has declined over the past
several years, especially those nesting on the Outer Hebrides (Flegg 1972;
Harris 1976).
It is difficult to find seabird species whose nesting grounds have not been
affected by humans but whose numbers have been censused. The best
illustrations of secular changes in relatively constant habitats are probably
those available in the British Trust for Ornithology's breeding censuses of
songbirds. Songbirds are short-lived and their populations change on
relatively short time scales. The northwestern European landscape has
remained relatively constant for the last 75 years, yet there are observable
decade-long trends—for example, of willow warblers (Phylloscopus
trochilus) and dunnock (Prunella modularis). There are detailed data on

population changes in great tits (Parus major) through the work of Kluyver
(1951), Lack (1964), and Perrins (1965).

Effects Reflecting Environmental Change

Nelson (1966) argued that the increase of gannets in the North Atlantic
during this century has been related to increasing temperatures rather than
(as usually ascribed) to increased food from fish damaged or escaped during
commercial fishing.
Ainley and Lewis (1974) described a particularly interesting example of the
effects of environmental change on seabird populations. The events begin
with the decrease of seabirds on the Farallon Islands off California as a
result of human depredations. Even after fowling was made illegal, the
populations of murres, double-crested cormorants (Phalacrocorax auritus),
and especially of tufted puffins (Lunda cirrhata) and pigeon guillemots
continued to decline as a result of oil pollution. During the last 3 decades
the smaller species of seabirds nesting on the Farallons, such as rhinoceros
auklets (Cerorhinca monocerata), have increased rapidly and the authors
suggest that their increase was abetted by an increase in the small prey fish,
northern anchovy (Engraulis mordax). One of course expects predators to
be affected by changes in the abundance of their prey. During this same
period, larger species of seabirds such as double-crested cormorants and
tufted puffins have failed to recover their numbers, and the authors
speculate that this failure is related to a decrease of the larger prey fish,
Pacific sardine (Sardinops caerulea).
A widely publicized impact of environmental fluctuation upon seabird
populations is that of the northeast wind, El Niño, off the Peruvian coast.
This wind pushes the upwelling Humboldt Current water offshore and
causes mass mortality in the Peruvian anchovies (Engraulis ringens) and, as
a consequence, a die-off among the millions of seabirds such as Peruvian
guanay cormorants (Phalacrocorax bougainvillii) and Peruvian boobies or
piquero (Sula variegata) which feed upon them (Murphy 1936).

Theoretical Considerations

Can useful generalizations be drawn from these observations on population
changes? Can a model be constructed of the forces which drive population
changes or of population-habitat interactions which keep populations from
extinction? Some conflicting theories and assumptions of population
dynamics are examined and discussed below.

The Assumption of Population Stability and of Closely Attuned Density-dependent Mortality

During the 5 decades before 1970, it was widely accepted that most animal
populations were generally stable and saturated before the arrival of the
white man. Although a few field biologists vigorously dissented,
"establishment" ecologists regarded fluctuations as a departure from the
norm, and as such, a hazard to the population. Many theorists of both
evolution and ecology argued that adaptations were required to damp
fluctuations or the fluctuations would become "random walks" and the
population would rapidly become extinct. As a consequence, relatively all
theoretical models included stability as a central assumption.
• The basic element of this theoretical complex has been the Lotka-Volterra
formula for a logistic curve of population growth and stabilization.
According to this formula it has been reasoned that by establishing the
inherent rate of increase of a population (i.e., its average natality relative to
mortality, or r) and by measuring the carrying capacity of the environment
(which is the density of the population at saturation, or K), one can predict
the maximally productive population size, and maximum rate of production
of new individuals (or maximum sustained yield). These assumptions have
supplied the theoretical framework for virtually all game management and
many fisheries practices.
Once stability was assumed, a mechanism for maintaining stability was
necessary. This mechanism was found in an interaction between the
population and the environment, called density-dependent mortality
(Nicholson 1933). The impact of this feedback has been assumed to cause
the point of inflection of the "sigmoid curve" and to regulate the density "at
equilibrium."
Populations growing in relatively isolated or closed systems have been
observed to follow a sigmoid curve toward a steady state. We have data on
the growth of several Massachusetts gull colonies which show this type of

short-period rapid increase followed by a long sequence of shallow
oscillations (Drury and Nisbet 1972). But usually observations have been
terminated at about the time the population passed through the point of
inflection.
• Lack (1954) accepted the principles formulated by Lotka-Volterra and
hence viewed Nicholson's (1933) density-dependence as logically
necessary. Lack (1948, 1954) argued that reproductive effort (clutch size or
litter size times the number of broods) must be as large as the parents can
successfully raise to independence because these biological characteristics
are directly subject to natural selection. He argued that because
reproductive potential is excessive (Darwin 1859), mortality must be
density-dependent if a population is to avoid fluctuations. The only
adequately density-dependent regulating process he accepted was the
population's response to its food supply (Lack 1954). In fact, for many
years Lack rejected Kluyver and Tinbergen's (1953) hypothesis that
territory could act as a control on population size in birds because, he
argued, territories were compressible and therefore allowed wide
fluctuations. To his credit, however, Lack eventually acknowledged this
mistake.
The first defect in the concept of "carrying capacity" is the idea that
populations have "mechanisms" or "institutions" (Wynne-Edwards 1959) by
which the population is kept stable at the carrying capacity in a stable
habitat.
The second defect in the concept of carrying capacity is that it presupposes
a stable environment. During the early decades of the 20th century most
climatologists believed that a departure from the norms of a regional
climate set processes in motion which would return the climate to normal.
During the last decades, however, climatologists and oceanographers have
shown clearly that environments are continuously in flux.

An Attack on Density-dependent Mortality

Some theorists rejected the concept of carrying capacity as soon as it was
formulated. Andrewartha and Birch (1954) predicted fluctuations would be
undamped by inherent population mechanisms but rather would be
controlled by external forces indifferent to the density. Their supporting

data were drawn from field studies of insects in arid climates. Some of their
ideas are directly relevant to seabirds; for example, their assertion that in
many cases limits to carrying capacity of the habitat are not set in a way
responsive to the density of the population. The number of occupiable
ledges on a seabird cliff are fixed and when they are full no more birds can
breed there regardless of the amount of food available. For another
example, some biological processes act in a way that reinforces
fluctuations. Predation can act in this way in the relatively closed system of
a seabird colony; i.e., the smaller the prey population the larger the
percentage taken by the predators. The importance of predation as a
selecting factor is shown by the adaptations marine birds and waterfowl
make to avoid it. The fact that large colonies of seafowl are usually
concentrated on isolated, predator-free islands is one obvious case (Lack
1966).
Although their ideas are useful in understanding changes in many species,
primarily insect populations, the generality of Andrewartha and Birch's
(1954) hypothesis is weakened because it conflicts with detailed studies of
seabirds which show that in many cases local food resources do limit
breeding success. Ashmole (1963) showed this for tropical terns, and Hunt
(1972) for some colonies of herring gulls on the New England coast.
Nettleship (1972), studying the effects of herring gulls on Atlantic puffins,
showed that the effect of harassment and stealing food from the parents was
to reduce the amount of food brought to the young and thus reproductive
success. In those parts of the colony where gulls were numerous or where
the puffins were at a disadvantage in escaping from gulls (i.e., flat rather
than steep slopes) the reproductive success of puffins was significantly
lower than in areas away from the gulls.
The literal application of Andrewartha and Birch's general ideas also
conflicts with observations on subtle adaptations some waterfowl have
made to counter predation.
Barry (1967) described the density-avoiding adaptations of arctic-nesting
geese to evade predation—specifically by foxes. Black brant (Branta
nigricans) nest on low coastal or delta islands seeking to escape by
remoteness. Snow geese (Chen caerulescens) are colonial on large, flat
areas, seeking protection in numbers. White-fronted geese (Anser albifrons)

are solitary nesters on inland swamps, seeking to be "over-dispersed"
among scrub willow.
Common eiders, black scoters (Melanitta nigra), tufted ducks (Aythya
fuligula), and other ducks select gull colonies as nesting habitat. Although
there is little doubt that the ducks choose gull colonies for nesting, there is
some doubt as to the reasons. Finnish biologists (summarized by Bergman
1957; Hildén 1965) have concluded generally that gulls protect the duck
nests from predation by hooded crows (Corvus corone).

The Assumption that Fluctuations Are Generally Present

Recently theorists have built models based on assumptions that fluctuations
are a general characteristic of population dynamics, such as Gilpin's (1975)
model describing multi-phased oscillations. He took account of the fact that
fluctuations (and models) become more complex as more species and
nonlinear effects are included. May and Leonard (1975) emphasized that
the effect of nonlinearities is to make it impossible to speak even in
principle of the equilibrium point of a community. They pointed out that
even though the model is deterministic (i.e., assumes that the system will
come to equilibrium) the oscillations are so complex that they may appear
to be random, and it may be a very long time before the system returns to a
position near its starting point. "On the other hand a truly random
ecological system could always be fitted by a suitably ingenious limit cycle.
This suggests that ecological analysis which does not consider component
processes must be viewed with great suspicion" (Gilpin 1975). May and
Leonard (1975) and Gilpin are both making a familiar point—that neither
the logic nor the interactions described in a formula will describe biological
reality unless the assumptions are correct. They are also making a different
point—that an ingenious mathematician can create a formula to describe
almost any operation (whether its workings are systematic or random), and
the formula may seem to work.
Gilpin's moral is that one cannot learn very much that is helpful by studying
fluctuations as such. One must study the factors controlling populations.
This is a very old idea.
It would appear that defining carrying capacity and inherent rate of increase
will not be very instructive in managing seabird populations other than in

speculating upon what might be ideal upper limits. It can also encourage the
musty sophistry that when a population increases beyond this abstract
carrying capacity it "needs" to be hunted to prevent overcropping resources
and damage to itself through a population decline. But we will not have the
time to carry out detailed studies of life histories seeking for critical
population-habitat interactions over several fluctuations for each species
involved in a disaster before designing programs to help seabird
populations to build up their numbers.

General Characteristics of Marine Birds and Waterfowl

Because general theory does not seem to work and because detailed studies
take too much time, I conclude that it is necessary to identify certain
general principles upon which to base applied programs. These categories
of knowledge include: (1) how vulnerable certain categories of seabirds,
waterfowl, and shorebirds are to specific types of disasters, (2) how quickly
their numbers build up after they have been reduced, and (3) at what stages
we can help them best (i.e., at the breeding grounds, at the winter gathering
grounds, or on migration). I believe that we already know enough to design
effective programs and to begin work. To this end some characteristics of
seabirds are identified which determine the population structures and ways
in which their numbers respond to changes in the environment.

Habitat

Although the shallow oceans, islands, and seashores are among the most
permanent features of the earth in general, the details of their numbers and
distribution change rapidly. Sandy shores are obviously being reworked
even in the short span of a single lifetime. Distribution of islands and the
sediment load, extent, and strengths of currents vary constantly in space and
change with time.
The food that seabirds use is patchy and subject to both short-and long-term
fluctuations in numbers and shifts in geography. Suitable breeding habitat is
scattered, and in many places where oceanic conditions provide a good food
supply there are no nesting sites. Consequently, seabirds aggregate in

colonies, often dense, and the colonies are clumped for geographical as well
as biological reasons.
Lack (1966) discussed some general features of how the breeding
adaptations of seabirds are adjusted to the distances the birds must go to
find food. The species which feed close to the nest characteristically
establish isolated territories or nest in small groups, and they accept many
different kinds of nesting substrate. Their clutch sizes are large, individuals
move nesting sites readily, and their young grow rapidly compared to the
species which feed far at sea. Species which feed far at sea aggregate in
large colonies. These species are often rigid in their requirements for
suitable nesting sites, their clutches are usually limited to one egg per
season, their young grow slowly, and there seems to be strong attachment to
traditional colony sites.

Breeding

Ashmole (1963) suggested that the clutch size of some oceanic birds is
small and colonies occupy only part of the available habitat because food
resources within efficient commuting distance of the breeding site are
limited. We can see this effect in the usual failure of common terns to raise
a third chick, even in the colonies that are surrounded by favorable habitat
(Nisbet 1973). Herring gulls whose colonies are close to sources of human
refuse raise more young than do those whose colonies are at some distance
(Drury 1963; Kadlec and Drury 1968; Hunt 1972).
Ashmole (1963) suggested that during the course of the breeding season the
birds exhaust the available food supply. The validity of this suggestion is
reflected in the long distances some species (petrels, boobies, murres,
dovekies) go for food to feed their young. One would therefore expect that
early nesting pairs would be more successful, and this seems to be the case
in herring gulls (Nisbet and Drury 1972), kittiwakes (Coulson 1966), and
red-billed gulls, Larus novaehollandiae (Mills 1973).
If food is in short supply and parents have to seek over a wide area for food
so that they can bring back only a little food at long time intervals, one
would expect these birds to have a small clutch and their young to grow
slowly, as is the case. One would also expect seabird colonies situated near
oceanic currents to be larger and more successful because food is

continuously renewed. Conversely, one would expect colonies next to still
waters to be smaller and less successful.
The small clutch size of seabirds means that when a population has been
reduced, it will grow slowly toward its former abundance. The growth rates
of seabird populations on the New England coast since their release from
human predation reflects this. Species such as black guillemots with only
two eggs per clutch and herring gulls with three eggs per clutch have
increased more slowly than have the populations of common eiders or
double-crested cormorants both with three to six eggs per clutch (Drury
1973).
If the species that nest in colonies show a high degree of site tenacity, they
are not likely to reestablish a colony after it has been eliminated. An
exception to this is the food subsidy provided by man, which seems to have
been important in creating a nonbreeding population of herring gulls large
enough to form a "critical mass" for the formation of a new gullery.

Age Structure

Because the main element of population size—the number of breeding
adults—is limited by the number of breeding colonies and the food
available to those colonies, one assumes that the total numbers of seabirds
is much less than could be supported by the larger areas of productive
oceans. Hence one suspects that there is lessened competition for food
outside the breeding season and that lack of competition for food is a major
reason for seabirds being long-lived, often to extremes little suspected until
recently. Mortalities of 10-12% per year are common, and some as low as
4% (wandering albatross, Diomedea exulans; Tickell 1968) have been
recorded.
In contrast, songbirds with large clutches, such as the titmice studied by
Kluyver (1951), produce a large number of young with whom they and
other adults must compete for food during the winter period of food
shortage. Because the titmice are permanent residents, they occupy all of
the available habitat throughout the year. Hence titmice suffer intense
intraspecific competition, which shortens the survival of adults. Kluyver's
experiments (1966) with nest boxes used by a closed population of great tits

on Vlieland, The Netherlands, showed that by artificially reducing clutch
size the survival of adults was increased.
Similar competition for the few territories available on marshes and
consequent shortened life expectancy, can be expected in waterfowl with
large broods. The effect should be less marked for geese with smaller
clutches that nest in less confined habitats.
The long life span of seabirds means that a population will have a large
component of older age categories; this characteristic has several
implications:
• It means that the population can survive years of reproductive failure
without the observable immediate effects that would be manifest in titmice,
grouse, or rabbits. Near failure of reproduction during a breeding season
among arctic seabirds at Bear Island was reported by Bertram et al. (1934).
Many similar observations have been made since then: Pitelka et al. (1955)
reported such a case among skuas and gulls at Point Barrow, Drury (1961)
for greater snow geese (Chen cerulescens atlantica) at Bylot Island, Jones
(1970) for black brant gathering at Isambek Lagoon on the Alaska
Peninsula, and D. A. Snarski (personal communication) for kittiwakes at
Cook Inlet. Reproductive failure can sometimes be chronic, as observed by
Nisbet (1972) for terns at Cape Cod, Massachusetts, or by Drury (1963) and
Hunt (1972) for herring gulls on the outer islands on the coast of Maine.
When reproductive failure becomes chronic as observed on peregrine
falcons (Falco peregrinus) by Hickey (1969) and in ospreys (Pandion
haliaetus) by Ames and Mersereau (1964), the population of adults may
hold on for a number of years without evident decline. Damage to the
structure of the whole population may be serious before any numerical
results are evident.
• Although there may not be intensive competition for food in the habitat
away from breeding colonies, there is intense competition for food and
breeding sites at and around the colonies. Hence age and previous
experience in seabirds assume importance in establishing territory and in
breeding success. Associated with this is the tendency for immature birds to
delay breeding until they are several years old and for the immatures to
remain on feeding grounds at some distance from the colonies. In some
cases young birds may "hang around" breeding colonies and even feed

some of the young. When young birds do first breed they usually lay
smaller clutches and raise fewer young than do older birds. The importance
of age and experience upon breeding success has been well documented for
kittiwakes (Coulson 1966) and red-billed gulls (Mills 1973).
The fundamental biological importance of this delayed maturity seems to be
emphasized by the persistence for several years of immature plumages, so
clearly identifiable that even a human observer can recognize the age of an
individual. One assumes such an evident feature must have adaptive
significance.

Wintering Grounds

When colonial nesting seabirds leave their breeding islands for their
wintering grounds, their identification with that island is lost as far as
population effects are concerned, because birds from many colonies mingle
on the wintering grounds. Major mortality takes place on the wintering
grounds and must therefore act on the species population as a whole rather
than differentially on individuals associated with especially dense colonies.
Such a direct relation between colony density and mortality would be
necessary for density-dependent mortality to regulate the number of birds
on a breeding colony. Conversely, one cannot expect that all colonies will
decrease equally because mortality should be equally distributed if all the
population gathers on a common wintering ground. Thus density-
dependence acts only in a very general way upon the sum of animals
considered as an abstract entity—the population.
In fact, on the wintering grounds, as shown by a graph of numbers of gulls
reported on Christmas Counts on Cape Cod, Massachusetts (Kadlec and
Drury 1968), herring gulls are very responsive to local conditions and move
several tens of miles to gather at favorable feeding sites. An aerial survey of
the gulls on the East Coast of the United States (Kadlec and Drury 1968)
showed that more than half of the gulls were gathered near major food
sources in large metropolitan districts. Most of the remainder were gathered
near small fishing ports. Very few were scattered along the shoreline in
what one assumes is the traditional gull habitat. Later analyses of the
relation between the distribution of banding recoveries of birds in their first
winter and the distribution of immatures as found on this winter census

(Drury and Nisbet 1972) suggested that proportionately more first-year
gulls died in those areas where the birds were sparsely distributed than died
in the crowded metropolitan areas.
These results suggest both that there is not a direct feedback between
reproductive rate and mortality, and that mortality may even be inversely
density-dependent on wintering grounds. This last runs counter to
traditional ecological ideas that density causes a change in mortality rate.
The idea that individuals gather where "living is easy" and mortalities are
low is consistent with the theory of natural selection. One would not expect
the food of the gulls to be evenly distributed, and one would expect
individuals to move away from areas where food is scarce and mortality is
high.

Differences in Breeding Success Between Colonies

Breeding success has been shown to vary among individual pairs of gulls
(Drost et al. 1961). Certain groups of individuals nesting in patches within a
single colony have greater breeding success than do others (Coulson 1968;
Drury and Nisbet, in preparation). Differences in breeding success also
occur between colonies (Frazer-Darling 1938; Kadlec and Drury 1968;
Drury and Nisbet 1972). Some colonies reproduce consistently better than
others—for example, the gull colonies close to fishing ports and
metropolitan areas. Other colonies produce consistently fewer young, such
as the colonies on the outer islands in the Gulf of Maine (Drury 1963;
Kadlec and Drury 1968; Hunt 1972). The populations of successful colonies
grow while the numbers of unsuccessful colonies decline, even during a
period of general population increase (Kadlec and Drury 1968).
The difference between success and failure, growth and decline, appears to
lie in the food available. Colonies increase where breeding success is high
and decrease where breeding success is low. One important reason seems to
be that adult gulls may move to a more productive colony even after they
have nested with another colony (Drury and Nisbet 1972; Kadlec 1971).
Such adaptations can be viewed as adjustments by which individuals meet
the requirements of an environment in which the availability of food and
other necessities is patchy and shifting.

Dispersal

In general terms, the willingness of some individuals to disperse while the
majority of individuals remain loyal to a colony can be considered a major
mechanism of population maintenance. If conditions deteriorate seriously at
one place so that the local populations decline or disappear, dispersal from
other centers can be expected to repopulate the area as soon as local
conditions again become suitable. This subject has been treated in more
detail by Drury and Nisbet (1972) and Drury (1974b).
Occupation of new, or return to former, nesting sites has been recorded in
detail for fulmars (Fulmaris glacialis) by Fisher (1952) and for herring
gulls by Kadlec and Drury (1968). Dispersal is also known for waterfowl.
Hansen and Nelson (1957) reported that of some 8,000 brant banded in
midsummer on the Yukon delta 8 were recovered in northern Siberia and 28
in northern Alaska and arctic Canada. They suspected that pairing on the
wintering grounds was responsible for the change in breeding areas, a
change that would not be expected among other North American species of
geese. Similarly, wide dispersal seems to occur in pintails (Anas acuta),
mallards (Anas platyrhynchos), and wood ducks (Aix sponsa).
The general tendency for some individuals to disperse and the frequency of
"extra limital" breeding attempts is especially well established in the Bering
Sea region, in part at least because vagrants from Siberia or North America
are readily identified as such. In the Aleutian Islands, Emison et al. (1971)
and Byrd et al. (1974) have enumerated the nesting vagrants. For the
Pribilof Islands, Kenyon and Phillips (1965), Sladen (1966), and Thompson
and DeLong (1969) have recorded the repeated appearance of birds of
Siberian distribution, and Fay and Cade (1959) and Sealy et al. (1971) did
the same for St. Lawrence Island.
One can conclude that a few individuals are constantly trying to settle in
new geographical areas. As climatic and habitat conditions change, some
populations are able to become established; for example, southern species
such as mockingbirds (Mimus polyglottus), cardinals (Cardinalis
cardinalis), and tufted titmice (Parus bicolor) have settled in southeastern
New England during the last 2 decades. These southern species have
received much publicity. But at the same time, a less publicized dispersal of
white-throated sparrows (Zonotrichia albicollis), hermit thrushes (Catharus

guttatus), and dark-eyed juncos (Junco hyemalis) has resulted in new
nesting records of more northerly species, also in southeastern New
England.
The ability (or lack of ability) of some organisms to expand their ranges
over time has been a subject of consideration for a number of years by plant
and animal geographers. An important botanical paper on this subject in the
Bering Sea region was presented by Hultén (1937), who analyzed the
ranges of plants of the area of Kamchatka, eastern Siberia, Alaska, and
northwest Canada, showing that diverse floras occur in some restricted
geographic areas. He called these areas "refugia," and postulated that many
species had survived Pleistocene glaciations in them because these refugia
remained ice-free. He, like Fernald (1925), was puzzled as to why only
certain species had been able to expand their ranges outward from these
"areas of persistence," while other apparently more "conservative" species
were unable to do so. Similarly, there appear to be conservative endemic
bird species of the Bering Sea region: the extinct Commander Islands
cormorant (Phalacrocorax perspicillatus), Steller's eider (Polysticta
stelleri), spectacled eider (Lampronetta fisheri), emperor goose (Philacte
canagica), whiskered auklet (Aethia pygmaea), least auklet (A. pusilla),
parakeet auklet (Cyclorrhynchus psittacula), Aleutian tern (Sterna aleutica),
red-legged kittiwake (Rissa brevirostris), bristle-thighed curlew (Numenius
tahitiensis), long-billed dowitcher (Limnodromus scolopaceus), surfbird
(Aphriza virgata), black turnstone (Arenaria melanocephala), rock
sandpiper (Calidris ptilocnemis), and western sandpiper (C. mauri).
The ranges of horned puffins (Fratercula corniculata), Kittlitz's murrelet
(Brachyramphus brevirostris) and, perhaps, crested auklet (Aethia
cristatella) suggest that some species of "Beringian" seabirds have
expanded their ranges from Hultén's (1937) "refugia."

Dispersal and Regional Persistence of Marginal Populations

The presence of several sub-elements of a species population and, therefore,
the opportunity for dispersion among alternative breeding sites may be an
important factor in the regional persistence of a species on the margin of its
range, as illustrated by the history of laughing gulls (Larus atricilla) in New
England.

Between 1875 and 1900 there were fewer than 50 laughing gulls in
Massachusetts (Mackay 1893) and about 35 in Maine (Norton 1924). In
Massachusetts the laughing gulls all settled on one large island, Muskeget,
where by 1940 there were about 20,000 pairs (Noble and Würm 1943).
Meanwhile, in Maine the population had been disturbed by sheep and men
and had shifted about among seven islands. The Maine population grew to
only about 350 pairs by 1940 (Palmer 1949).
The laughing gull population in both States has decreased since 1940. In
Massachusetts, where all pairs occupied one island, the population had
fallen to about 250 pairs by 1972, but the Maine population, still divided
into five colonies, stabilized at 250 pairs (i.e., the same as instead of only
1% of the Massachusetts population).

Use of General Principles in Solving Conservation Problems

Game biologists have successfully maintained the populations of hunted
animals by using a number of classical principles of game management.
They have controlled mortality by regulating kill and have increased
standing stock by improving habitat on a local scale. This seems to have
worked in species which are short-lived, have large clutch sizes or litters,
and which occupy mosaics of highly productive "successional habitat."
Seabirds, however, contrast with these species in a number of important
biological characteristics. They have small clutches, postpone breeding until
they are several years old, and are subject to periodic or chronic
reproductive failures. Therefore, their populations are skewed toward older
animals and replacement of lost individuals is slow. Many seabirds, like
some geese, have a high level of site tenacity and thus may resist
recolonization or fail in the attempt to recolonize a breeding site once
eliminated from it. In those species studied it appears that the breeding birds
at a small percentage of colonies are responsible for a large proportion of
the annual crop of young. It is probably dangerous, therefore, to risk either
damage to or elimination of well-established colonies.
Studies of kittiwakes by Coulson and White (1958, 1961), sooty terns
(Sterna fuscata) by Ashmole (1963) and Harrington (1974), Atlantic puffins
by Nettleship (1972), and Cassin's auklets (Ptychoramphus aleutica) by
Manuwal (1974), and the practice of eider "farming" in Iceland indicate that

the number of available territories or breeding sites may limit the size of a
population and that populations can be increased by increasing the number
of sites available. This suggests one way in which direct steps can be taken
to encourage the numbers of breeding seabirds. Other studies indicate that
seabirds will move into synthetic habitat such as created by the window
ledges on buildings (Coulson and White 1958) or the islands created by
dumping spoil from channel dredging operations (Buckley and Buckley
1971, 1975; Soots and Parnell 1975).
Most generalizations of population biology have been derived from the
study of insects, songbirds, or game species. It seems inadvisable to assume
that those principles will apply to seabirds without modification. For
example, predation by gulls and ravens may have a disastrous effect on a
seabird colony at low colony density but have progressively less impact as
the colony size and density increase. Fox predation may have important
effects over most ranges of prey density because the presence of foxes has
important psychological effects.
The habitats of seabirds include elements in which birds are widely
dispersed (feeding areas) and others in which birds are crowded and
narrowly localized (nesting sites). Thus effective programs of conservation
should include guarantees that a number of colony sites be available in as
widely dispersed a pattern as possible. Each productive feeding ground
should, if possible, have several colony sites available.
We have argued elsewhere (Drury and Nisbet 1972; Drury 1974a) that one
of the chief defenses any population has against extinction is the
combination of being divided into a number of population centers with
having some movement of individuals between the centers, but not too
much. Because it is highly improbable that a single catastrophe will affect
more than a part of a species' range at any time, the more numerous and
widely scattered the partially independent segments of a population are, the
better the species is insured against extinction. This, of course, suggests that
the size of each colony may be less important for long-term survival than is
the total number of colonies.
One intuitively concludes that "conservative" species, such as those
endemic to the Bering Sea region (whose dispersal and colonizing
mechanisms seem to be poorly developed), are especially vulnerable to the