Chapter II: Front Matter (2)

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] 1973_c_; 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 (1900_a_) described the birds he observed in the Kotzebue Sound area.

Cursory aerial surveys conducted by J. C. Bartonek, J. G. King, and D. R. Cline (U.S. FWS 1973_a_; 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 1973_a_, 1973_b_; 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 1973_a_, 1973_b_; 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 (1900_b_) 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 1973_a_).

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 (1973_c_).

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.

_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.

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