On the cold waters of the Alaska Peninsula, buoyant lines of Steller's Eider are punctuated by the bright white heads of the males. This diving duck may seem far removed from the usual threats to waterbirds. But, perhaps like the Labrador Duck, which went extinct before its life history was understood, the Steller's Eider has been slowly declining for decades, for unknown reasons. Smallest of the world's four eider species, it is now the least numerous.
On average, the Steller's Eider is 17 inches long, with a 27 inch wingspan, and weighs 1.9 pounds. This eider is a small diving duck with a squarish head and compact frame. In breeding plumage, the male Steller's Eider is remarkable. The drake's head is white with a blackish patch on the rear crown, black over the eye, and a greenish patch between the eye and the blue-gray bill. A black collar, throat, and chin separate the white upper neck from the light orange wash over the chest, belly, and sides. A black circle beside the breast punctuates this orange. At rest, the drake's upper parts are black with bold, wavy white lines. In flight, the wings flash large white patches. Non-breeding males, females, and juveniles appear brownish overall.
In Alaska, the range of the Steller's Eider has been shrinking dramatically since the 1960s. It now breeds at only a few scattered locations along Alaska's central and northern coast, with greatest densities near Barrow. Two other populations breed along Russia's Arctic coastline. In North America, its winter range is almost entirely confined to the Alaska Peninsula west of Cape Douglas through the Aleutian Islands. Steller's Eider also winters north of the Arctic Circle in Europe and along the coast of Russia's Kamchatka Peninsula.
A legend for the range map to the right can be found
here.
Most of the year, the Steller's Eider frequents clear coastal waters such as shallow lagoons, tidal flats, and shoals. Deeper bays appear important when shallows are iced. This diving duck breeds on coastal plains and only on the Alaskan Arctic tundra in North America. Proximity to shallow water, dry grasses, sedges, and low scrubby plants characterize nest sites.
The Steller's Eider can dive 50 times in an hour and stay submerged for 45 seconds. Large foraging flocks often dive in unison and form long lines on the surface. Small aquatic animals are gleaned from underwater vegetation and from the sea floor. The diet of the Steller's Eider includes mollusks, marine worms like bristle worms (
polychaetes), sea dollars and other echinoderms, small fish, lamp shells (
brachiopods), shrimp-like crustaceans called scuds (
amphipods), sow bugs, blue mussels, and macoma clams. During breeding season on the tundra, insects such as midge larvae, crane flies, caddisflies, stonefly larvae, water beetles, and water boatmen become important food sources.
Remote, inhospitable terrain still hampers knowledge of the Steller's Eider's breeding habits. Monogamous pairs form in early spring but do not nest until mid-summer, when ice still covers much of the open tundra. Groups of three to seven males court a female with displays that include ritualized bathing and exaggerated head tosses. While the male distracts potential predators with slow flights, the female chooses a nest site in a dry meadow or low scrubland. In a shallow bowl lined with grass, moss, lichen, and down, the female lays five to seven olive-buff eggs, which she incubates alone for about 26 days. As incubation begins, males flock in nearby pools and lakes to prepare for migration.
The dark brown, downy chicks are "precocial," or well developed enough to walk and probably swim within a day. Little is known about their development. Females and immatures depart the breeding grounds together in late August.
Arctic ice forces all Steller's Eiders to migrate south, and variations in weather patterns shift wintering ranges. Fall migration is generally staggered: adults that fail to breed go first, followed by breeding males, and finally females and juveniles. Small flocks travel over sea and along coastlines to gather at favored wintering and molting sites, like Izembek Lagoon, but routes are not known. Spring migration is most apparent in May, and many Steller's Eiders move westward through the Bering Strait. Most Eurasian breeders winter in North American waters.
Fredrickson, L. H. 2001. Steller's Eider (
Polysticta stelleri). In
The Birds of North America, No. 571 (A. Poole and F. Gill, Eds.). The Birds of North America, Inc., Philadelphia, PA.
Kaufman, Kenn.
Lives of North American Birds. Houghton Mifflin Company, New York, 1996.
Sibley, David Allen.
The Sibley Guide to Birds. Alfred A. Knopf, New York. 2000.
