Steller’s eider (Polysticta stelleri)

GenusPolysticta (1)
SizeLength: 45 cm (2)

Steller’s eider is classified as Vulnerable (VU) on the IUCN Red List (1) and is listed on Appendices I and II of the Convention on Migratory Species (CMS) (3). It is also listed on Annex 2 of the African-Eurasian Migratory Waterbird Agreement (4), as a US Threatened Species under the US Endangered Species Act in 1997 (5), and as an Alaskan Species of Special Concern (2).

Distinctive in its breeding plumage, male Steller’s eiders have an orange breast and sides, and a white head, all contrasting against a background of black. On close inspection, small green spots may be visible in front of the eye and on the back of the head. Males in non-breeding plumage and females are a simple brown with a light eye-ring. This duck has a flat head, long tail, and a short, triangular bill (6).

Two fairly distinct populations of Steller’s eider exist, separated by the Khatanga Gulf, in Russia. One breeds west of the Khatanga, in western Russia, and winters in northern Europe around the north-east Atlantic Ocean and the Baltic Sea. The other population breeds east of the Khatanga, in eastern Russia and the arctic plain of Alaska, and spends winter along the Bering Sea (2) (7). Small numbers of Steller’s eider also winter in northern Japan (7).

During the breeding season Steller’s eider is found in open tundra near to pools, bogs, rivers and lakes, but in winter it prefers to keep to the shore and is found on rocky coasts, and in bays and estuaries (8).

During the non-breeding season, when flocks of Steller’s eider inhabit salt water, remarkable synchronised foraging can be observed, with large flocks diving and resurfacing in unison as they feed on marine worms, clams, mussels, snails, limpets, shrimp and crabs (2) (6) (9). During the breeding season when Steller’s eider inhabits tundra wetlands, it is thought to feed on insect larvae, seeds, shrimps and flies (2).

Shortly before departure from the wintering range, Steller’s eiders pair up, migrating together to their breeding habitat (6) (9). Upon arrival, the female selects a nest site, hollowing out a bowl and lining it with grasses, lichens and down (6). Steller’s eiders lay clutches of around five eggs, which are incubated for 24 days (10). Steller’s eiders do not nest every year, but interestingly, it has been observed that they tend to nest in years when there is a abundance of lemmings, nesting pomarine jaegers (Stercorarius pomarinus) and snowy owls (Bubo scandiacus). This is thought to be for two reasons; an abundance of lemmings may provide an alternative prey source for foxes and other predators of eiders; while jaegers and owls may unintentionally provide protection to nearby nesting eiders whilst protecting their own nests (10).

Declines in populations of this striking bird are of great concern (2), and while the causes of these declines are not known, several factors may have contributed. Hunting is not thought to be a major threat, although lead poisoning has been noted as being prevalent in Steller’s eiders. An increase in predation levels may also have contributed to the decrease in numbers (6) (7).

Conservation efforts are hampered by the isolation and harsh habitat of this species, which makes research and surveying particularly difficult. However, a European Action Plan for Steller’s eider was published in 2000. It recommends the removal of threats, the maintenance of the current population, and surveys to establish the full range. Steller’s eider is a protected species in both Russia and the USA, as well as in several other countries in the Arctic. The United States Fish and Wildlife Service has designated a large amount of coastal habitat as a protected area for the conservation of this species (7).

For further information on the Steller’s eider see:

Authenticated (15/09/08) by Paul Flint, Research Wildlife Biologist, Alaska Science Center.

  1. IUCN Red List (November, 2011)