The smallest of the world's 4 eiders, the Steller's has morphological and behavioral similarities to dabbling ducks, as reflected in the original description of the species as Anas stelleri by Pallas in 1769. Georg Wilhelm Steller discovered Steller's Eider during the winter and early spring of 1740–1741 near Kamchatka, Russia, and saw the species again while stranded at the Russian end of the Aleutian chain ( Mearns and Mearns 1992b ). Many of Steller's bird skins survived the expedition, and Pallas named the species after its discoverer.
Steller's Eider has a range restricted to northern latitudes, where it nests near freshwater tundra ponds but shifts to shallow marine waters once breeding is complete. There are 2 populations of this species, a small Atlantic one that breeds in western Russia and winters in northern Europe and a larger Pacific population that breeds primarily in eastern Siberia and winters in Pacific waters. This small eider is frequently the most common breeding duck in the Arctic Coastal Plain near Barrow, Alaska—its primary breeding area in North America. The larger Russian population nests in coastal tundra and large river deltas. In contrast to the larger eiders that tend to move to deeper water in northern seas during winter, this eider generally inhabits the littoral zone of shallow coastal lagoons and inshore habitats. In North America, few individuals winter south of Alaskan waters.
Foods consumed by Steller's Eider in marine waters include a diverse array of marine organisms (crustaceans, marine worms, gastropods, and mollusks), contrasting with the high consumption of mussels by King (Somateria spectabilis) and Common eiders (S. mollissima). Aggregations of nonbreeding and failed breeders form in northern Europe and in the Pacific from Japan to Alaska beginning as early as July. Well-known large aggregations form along the Alaska Peninsula at Nelson Lagoon in summer and at Izembek Lagoon in fall and again in spring. Many individuals molt at these lagoons, and much of our understanding about wintering Steller's Eider stems from investigations at these sites. The large numbers of flightless birds that have been banded at Izembek Lagoon, beginning in the 1960s, have provided important information on homing, longevity, survival, and movements.
Concern about declining breeding populations is global. The decline of breeding in Alaska led to listing this population as Threatened in July 1997. Likewise Steller's Eider was recognized as a Category 3 or “rare” species in the Red Book for the Yakutia Republic in 1987 because of reduced breeding range, declining numbers, and illegal harvest.
Small ephemeral flocks are characteristic on breeding habitats. In contrast, Steller's Eider is highly social away from the breeding grounds, where it regularly occurs in large flocks, probably as a defensive adaptation to escape large avian predators. The species is noted for synchronous diving, an especially spectacular foraging behavior performed by large groups in late winter before departure to breeding habitats.
Pairs breed in tundra habitats that contain abundant small freshwater ponds often associated with northern river deltas and the Arctic Coastal Plain. Although favored nest sites usually are described as hummocks among tundra ponds with short vegetation dominated by sedges (Carex spp.), lichens, and sometimes willow (Salix spp.), not all nests are on elevated sites. On freshwater breeding habitats, seeds, macroinvertebrates (Chironimidae and Tipulidae) larvae, Eubranchiopoda (fairy and tadpole shrimp) become primary foods. Breeding success appears related to the abundance of brown lemming (Lemmus trimucronatus) at Barrow, AK, because high nest success coincides with high lemming populations.
Compared to many North American diving and dabbling ducks, information on this species is limited. Remote distribution on 2 continents with different governments, cost of logistics in remote areas, and severe environmental conditions during much of the year make investigations and communication among scientists difficult and expensive. Nevertheless investigations on breeding biology by L. Quakenbush, P. Flint, and M. Johnson in Alaska and D. Solovieva in Russia and on survival and homing by P. Flint and C. Dau have added greatly to understanding this poorly studied eider in the late 1990s (Solovieva Solovieva 1997a , Solovieva 1997b ; Flint and Herzog 1999 ; Quakenbush and Suydam 1999 ; Dau et al. 2000 ; Flint et al. 2000 ).