Steller's Eider

The Steller's eider, Polysticta stelleri, is a diminutive and agile Arctic sea duck, distinguished as the smallest and swiftest flying member of the eider species. Exhibiting sexual dimorphism, the male, or drake, is resplendent in breeding plumage with a striking contrast of black and white, accented by light-green patches and a cinnamon breast, while the female, or hen, dons a more subdued palette of browns.

Identification Tips

Observers should note the male's black cap, chin, throat, and rump, set against a white head and shoulders during the breeding season. The wings are adorned with white stripes on an iridescent bluish-purple background. Females and juveniles share a similar coloration of dark to cinnamon brown, with a pale-white eye-ring and bluish-purple speculums edged in white on their wings.

Habitat

Steller's eiders favor marshy tundra for nesting, selecting areas with water sedge and pendant grass. They are also found in coastal bays and lagoons during winter, where they forage in sheltered waters.

Distribution

This species breeds along the coastlines of eastern Russia and Alaska, with three distinct breeding populations. The Russian-Atlantic population winters in the Barents and Baltic seas, the Russian-Pacific population in the southern Bering Sea and northern Pacific Ocean, and the Alaska-breeding population also in the southern Bering Sea and northern Pacific, with less than 1% of the global population nesting in Alaska.

Behaviour

Steller's eiders are known for their specialized foraging techniques, including diving, wading, and dabbling near the shore. They exhibit a preference for small prey and are adept at catching highly mobile crustaceans. During the non-breeding season, they form large, dense flocks for molting.

Song & Calls

The male's vocalizations include a low, growling sound, while the female emits a discrete "qua-haaa." Notably, males court females in silence, and their feathers produce a mechanical whistling sound in flight.

Breeding

Breeding pairs form in late winter to early spring, with males displaying elaborate, silent courtship behaviors. Females lay 1-8 olive to brownish-orange eggs, incubating them alone for about 25 days. The precocial young are independent feeders, though the female remains protective for up to 35 days post-hatch.

Similar Species

Steller's eider can be confused with other eider species, but its smaller size, distinctive breeding plumage in males, and unique vocalizations help differentiate it.

Diet and Feeding

The diet consists mainly of crustaceans, mollusks, echinoderms, polychaete worms, and mussels, with a summer diet in the tundra including aquatic insects and plant material.

Conservation status

The Steller's eider is classified as Vulnerable by the IUCN, with threats including climate change, lead poisoning, nest predation, natural resource exploitation, and disease. Conservation efforts are underway, including the designation of critical habitats and recovery plans by the U.S. Fish and Wildlife Service and the European Union.

Cultural significance

Once a target for waterfowl hunters in the U.S., hunting of Steller's eiders ceased in 1991. Subsistence hunting and egging occur in Alaska but are uncommon, while the impact of such practices in Russia is not well-documented.