Steller's Eider

Polysticta stelleri

Description

The Polysticta stelleri (Steller's eider), the smallest of four eider species, was first described in 1769 as Anas steller and then subsequently grouped with the other eiders in the genus Somateria. The Steller's eider is now recognized as the monotypic genus Polysticta stelleri.

The adult male Steller's eider has a white head with a greenish tuft and a small black eye patch, a black back, white shoulders, and a chestnut breast and belly with a black spot on each side. Adult females and juveniles are mottled dark brown. Both adult sexes have a blue wing speculum with a white border. The Inupiat Eskimo name for this eider is Iginikkauktuk, while Yupik Eskimos call them Anarnissaguq. The Siberian Yupik name used by residents of St. Lawrence Island is Aglekesegak.

Behavior

Steller's eiders are sea ducks that spend the majority of the year in shallow, near-shore marine waters where they feed by diving and dabbling for molluscs and crustaceans. Their principal foods in marine areas include bivalves, crustaceans, polychaete worms, and molluscs. Steller's eiders move inland in coastal areas during the breeding season, nesting adjacent to shallow ponds or within drained lake basins. Here their diet includes chironomid larvae, plant materials, crustaceans, and mollusks.

The current breeding distribution of the Steller's eider encompasses the arctic coastal regions of northern Alaska from Wainwright to Prudhoe Bay up to 54 mi (86.9 km) inland, and Russia from the Chukotsk Peninsula west to the Taimyr, Gydan, and Yamal peninsulas. The actual numbers of Steller's eiders that nest in Alaska and Russia are unknown, although the majority of them nest in arctic Russia. After the nesting season, Steller's eiders return to marine habitats where they molt. Concentrations of molting Steller's eiders have been noted in Russia, near St. Lawrence Island in the Bering Sea, and along the northern shore of the Alaska Peninsula. Groups of tens of thousands have been observed to molt in the bays and lagoons along the Alaska Peninsula, in particular Nelson Lagoon and Izembek Lagoon. In other years, many of the birds complete their molt before arriving on the Peninsula. Band recoveries show that nesting Steller's eiders from both Russia and Alaska come together to molt in southwestern Alaskan waters.

During winter, most of the world's Steller's eiders concentrate along the Alaska Peninsula from the eastern Aleutian Islands to southern Cook Inlet in shallow, near-shore marine waters. They also occur, although in lesser numbers, in the western Aleutian Islands and along the Pacific coast, occasionally to British Columbia. A small number also winter along the Asian coast, from the Commander Islands to the Kuril Islands, and some are found along the north Siberian coast west to the Baltic States and Scandinavia. In spring, large numbers concentrate in Bristol Bay before migration; in 1992, an estimated 138,000 Steller's eiders congregated before sea ice conditions allowed movement northward.

Habitat

The Steller's eider inhabits shallow, near-shore marine waters, where it feeds by diving and dabbling for benthic molluscs and crustaceans. During the breeding season, it moves inland in coastal areas, where it nests beside shallow ponds or in wet-lands formed of drained lake basins.

Distribution

The worldwide status of Steller's eider has been poorly documented; few population surveys. have been conducted in Russia where the species primarily occurs through most of the year. When not in Russia, Steller's eiders live in marine areas where large-scale surveys are difficult and expensive, and their distribution varies within and among years in response to weather and oceanic factors. The variance in repeated counts in specific areas is therefore too high to identify statistically significant population trends. Steller's eider, relative to many other waterfowl species, is also not an important sport or subsistence species; consequently, it has received less scrutiny than it deserves.

Anecdotal observations suggest that Steller's eider numbers may have been declining range-wide for a number of decades. Dement'ev and Gladkov reported in 1952 that the enormous flocks wintering near the Commander Islands at the turn of the twentieth century had greatly declined by the 1930s. It also appears that the number of wintering Steller's eiders may have declined in recent years along the Alaska Peninsula where the majority of the worldwide population winters.

The worldwide population is still sizable— 138,000 were counted in Bristol Bay in 1992—and it is likely that this count did not include the entire worldwide population. For this reason, only those Steller's eiders that nest in Alaska are listed as threatened.

The Steller's eider once nested over a considerably greater area in Alaska than it does now. It historically nested in western Alaska and the North Slope and it still occurs in the latter general region but is essentially extirpated from the former. Appearing in western Alaska primarily in the coastal fringe of the Yukon-Kuskokwim Delta, the Steller's eider was common in some areas in the 1920s and was still present in the 1960s. The historic range of this bird on the North Slope extended from Wainwright east almost to the United States-Canada border. The species has abandoned the eastern North Slope in recent decades, but it still occurs at low densities from Wainwright to at least as far east as Prudhoe Bay. This species had largely vanished from the Yukon-Kuskokwim Delta by the 1960s or 1970s. Researchers failed to find any nests in the Kokechik Bay area in the 1960s, in sharp contrast to the situation in 1924, when the bird was described as "surprisingly common." Although pairs displaying nesting behavior were observed near the Kashunuk River as late as 1973, no nests were found in the area after 1963. Nesting was documented along the Opagyarak River in 1969 and again in 1975; the single nest found in 1975 was the last documented nesting attempt on the Yukon-Kuskokwim Delta until a pair nested unsuccessfully near the Kashunuk River in 1994.

Steller's eiders also apparently nested in low numbers in several widely scattered areas in southwestern Alaska, including the Seward Peninsula and St. Lawrence Island, but no nesting Steller's eiders have been found since the 1950s.

Steller's eiders still occur regularly, though not annually, near Barrow, at the northernmost tip of Alaska. In some years, up to several dozen pairs may breed. The area immediately surrounding Barrow is relatively accessible, and bird studies have been conducted there for decades; consequently, there are records of the presence or absence of this bird from 1900, 1958, and 1975-1981. More intensive studies were initiated in 1991 on the nesting biology, predation, and habitat selection of Steller's eiders in the area. In contrast, elsewhere on the North Slope, the species apparently occurs at extremely low densities over a huge area and use of specific nesting localities appears to be irregular.

Sightings made during extensive aerial surveys of waterfowl breeding pairs provide the most comprehensive view of the distribution of Steller's eiders on the North Slope. Aerial searches for nesting eiders were conducted on the arctic coastal plain of the North Slope from 1992-1996. Intensive aerial searches in 1995 of two areas where this taxon had been previously observed were conducted near Teshekpuk Lake and near the mouth of the Chipp River; not a single Steller's eider was seen. Steller's eiders have been observed recently near Prudhoe Bay during intensive eider searches conducted from the ground. Although the species was not recorded during the 1980s, a few pairs were seen each year between 1992 and 1994, and a female with young was seen in 1992. In 1991 it was estimated that a maximum of 3,500 pairs may have nested on the Yukon-Kuskokwim Delta.

The number of Steller's eiders nesting on the North Slope has also likely seen a similar decrease in recent decades as a result of their abandonment of several previously used nesting areas. Nesting Steller's eiders have been documented in recent decades only at Barrow; on the lower Colville River, where a female with young was seen in 1987; and near Prudhoe Bay, where a female with young was seen in 1993.

The species no longer nests on the Yukon-Kuskokwim Delta or other areas in western Alaska, and is now found exclusively on the North Slope.

Threats

Habitat modification and destruction do not appear to have played a major role in the decline of breeding Steller's eiders in Alaska. The species disappeared from the Yukon-Kuskokwim Delta and the eastern North Slope, although only a very small portion of the habitat in those areas has been affected by human activities. Other waterfowl species continue to nest in large numbers in these areas, demonstrating that what little habitat modification has taken place has not precluded waterfowl nesting. However, the factor or factors causing the decline are not understood.

The current range of Steller's eiders on the North slope is largely contained within the National Petroleum Reserve-Alaska, which was set aside for oil and gas development. The National Petroleum Reserve Productions Act of 1976 encourages expeditious leasing and permitting of oil exploration and development activities in Petroleum Reserves. Although very little of National Petroleum Reserve-Alaska has been leased, future leasing is possible in areas where industry interest is sufficient. The potential impacts of oil and gas exploration and development on nesting Steller's eiders are not known, but these birds frequently feed at Barrow in ponds within meters of the gas pipeline and nest successfully within a few hundred meters of the pipeline and the accompanying service road.

All but two of this bird's recently seen nests in the North Slope have been near Barrow, the largest Native village in northern Alaska. The human population of Barrow increased from 2,267 in 1980 to 3,469 in 1990, an increase of 58%, and village expansion is likely to continue in the future. Housing developments, gas field access and development, and conveyance of land from the Ukpeagvik Inupiat Corporation to shareholders could lead to nesting habitat loss and disturbance to nesting birds. Although Steller's eiders nest successfully along heavily used all-terrain vehicle trails and directly under approach lanes to the airport that are used daily by large jets and numerous smaller aircraft, the indirect effects of development and human presence can be detrimental to Steller's eiders. Fifteen adult Steller's eiders were found dead near Barrow between 1991 and 1994, five of which had been shot and one which presumably died from striking wires.

Much of the former Steller's eider breeding range in western Alaska is within the Yukon Delta National Wildlife Refuge and is protected from major development, although some of the habitat where the species previously bred is on Alaska Native land where Federal involvement in protection is low. However, the likelihood that large-scale development will take place in this remote region is limited. Because of the large amount of unaltered habitat available on the Yukon-Kuskokwim Delta, it is unlikely that the recovery of Steller's eiders and the development of Native-owned private lands in the area will both proceed to the point that they conflict.

Steller's eiders occupy a vast expanse of marine habitat during the non-nesting season. Within the marine distribution of the Steller's eider the environment has likely been affected by any number of human activities, including marine transport, commercial fishing, and environmental pollutants. There is as yet no direct and firm evidence that modifications of the marine environment have caused the decline of the Alaska breeding population of Steller's eiders. Substantial portions of the important molting and wintering areas have been designated as National Wildlife Refuges, State Game Refuges, or State Critical Habitat Areas.

Natural predators of Steller's eiders in Alaska include raptors, gulls, jaegers, ravens, and foxes. Arctic foxes (Alopex lagopus ) may have contributed to the extirpation of the Steller's eider on the Yukon-Kuskokwim Delta through increasing predation pressure when major goose populations in the region crashed during the 1960s, but this remains unproven. Some predators may be increasing in number as a result of human habitation and development. Predators and scavengers such as gulls, ravens, and foxes have increased in number due to the availability of refuse and handouts. Gulls and ravens are effective predators of eider eggs and young, while foxes depredate eggs, young, and adults. Predation is likely to increase near communities where refuse is available and could significantly affect eiders in these areas; in fact, seven of 15 adult Steller's eiders found dead near Barrow between 1991 and 1994 were believed to have been killed by predators. In addition, 17 of 26 nests found during this period had failed, and eight of these failures were believed to have been caused by avian predators or foxes. It is unknown how the rates of predation of adult eiders and eggs from nests have been affected by the possible artificial increase of predators in the Barrow area.

Spring and summer subsistence hunting of eiders in Alaska is currently in violation of the Migratory Bird Treaty Act, which prohibits hunting for most migratory birds between March 10 and September 1. However, that residents of certain rural areas in Alaska depend on waterfowl as a customary and traditional source of food; as such, authorities have exercised discretion in enforcing seasonal restrictions to allow for traditional subsistence use of many species. Starting in 1994, the U.S. Fish and Wildlife Service began to include Steller's eiders on the closed-season species list, indicating that restrictions on taking Steller's eiders during all seasons would be enforced as violations of the Migratory Bird Treaty Act. Modifications to the treaty have recently been made to legalize subsistence harvest during spring and summer.

Alaska Natives at several villages historically hunted Steller's eiders and their eggs for food, but many villages along the Steller's eider migration route have not been surveyed so the total annual subsistence harvest is unknown. However, Steller's eiders are not a preferred species, and they have been taken in far fewer numbers than the other three eider species. While not an important subsistence species, Steller's eiders are occasionally killed by accident in the hunting of preferred species.

Some currently unknown factors—natural, man-made, or combination of both—caused the extirpation of the Steller's eider from the Yukon-Kuskokwim Delta and the eastern North Slope. These proposed factors are changes in the Bering Sea environment where Steller's eiders molt and winter and ingestion of lead shot on the Yukon-Kuskokwim Delta.

Recent changes in the Bering Sea ecosystem may have affected the spectacled eider, which was classified as threatened in 1993 due to rapid population declines on the Yukon-Kuskokwim Delta and elsewhere within its range. Increasing Pacific walrus (Odobenus rosmarus ), gray whale (Eschrichtius robustus ), and sea otter (Enhydra lutris ) populations may have restructured the marine community that forms the prey base of these species, and this in turn may have affected other members of the community. Similarly, changes in commercial fishing pressure may also have affected the marine ecosystem with possible effects upon marine birds, including eiders. Other species in the Bering Sea have recently declined in numbers, including Steller's sea lions (Eumatopias jubatus ) and oldsquaws (Clangula hyemalis ). Declines in these species may have been caused by the restructuring of the trophic system or, alternatively, the declines may suggest a general deterioration of the Bering Sea ecosystem caused by contamination or other environmental factors. There is currently no documented link between changes in the marine environment in Alaska and a contraction of the breeding range of Steller's eiders in Alaska.

It has recently been shown that lead shot, used for hunting waterfowl for many decades on the Yukon-Kuskokwim Delta, is being ingested by spectacled eiders with potentially serious effects upon adult survival. Although nontoxic shot is now legally required for waterfowl hunting, illegal use of lead shot on the delta continues. Furthermore, it appears that lead shot may remain in tundra wet-land areas for many years, possibly decades, after deposition. There is no evidence indicating that ingestion of lead shot caused the extirpation of Steller's eiders on the Yukon-Kuskokwim Delta, but the ingestion of lead shot may have affected the species in some heavily hunted areas. The Alaska Department of Fish and Game and the U.S. Fish and Wildlife Service (FWS) are implementing educational programs, to be followed by increasing enforcement, aimed at eliminating the use of lead shot.

Conservation and Recovery

The FWS anticipates consultation with the U.S. Army Corps of Engineers and the U.S. Department of Transportation to avoid impacts to Steller's eiders from wetland fill permitting and other activities on the North Slope. Consultations to identify potential effects on Steller's eiders are also expected with the U.S. Bureau of Land Management for National Petroleum Reserve-Alaska lands issues, the Minerals Management Service for outer continental shelf oil and gas lease sales, and the National Marine Fisheries Service for commercial fishing regulations.

The FWS will initiate development of a recovery plan for the Steller's eider promptly upon listing. This recovery plan, prepared in cooperation with the affected agencies and communities, will establish recovery goals and set recovery task priorities. An educational program to gain public support for the protection of this bird has already been initiated and will be expanded cooperatively with affected communities.

Contact

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1011 E. Tudor Rd., Room 135
Anchorage, Alaska 99503
Telephone: (907) 786-3909
Fax: (907) 786-3844
http://alaska.fws.gov/

Reference

U.S. Fish and Wildlife Service. June 11, 1997. "Threatened Status for the Alaska Breeding Population of the Steller's Eider." Federal Register 62(112): 31748-31757.