Steller's Eider Life History

Habitat

Habitat Lakes and Ponds

In the High Arctic, Steller’s Eiders nest near the coast in marshy tundra with abundant water sedge and pendant grass. They nest in drier portions of this habitat, on small ridges or hummocks, where mosses and lichens mix with the sedges and grasses. Migrants move to coastal lagoons in the Arctic that are relatively shallow; they gather in large flocks and molt their flight feathers in these sheltered, food-rich environments. They forage in the lagoons, in eelgrass meadows, on the associated tidal flats, and also in coastal waters nearby. While molting they are unable to fly, and so they rest on adjacent beaches, mudflats, and sandbars. After finishing molt and regaining their ability to fly, Alaska-nesting Steller’s Eiders migrate to the Aleutian Islands, wintering from Kodiak Island west to Unalaska Island. Here they inhabit mostly bays and lagoons but also forage in deeper, usually sheltered waters.

Back to top

Food

Food Aquatic invertebrates

On the breeding grounds, Steller’s Eiders feed heavily on the larvae of midges, stoneflies, craneflies, beetles, water boatmen, small crustaceans (fairy and tadpole shrimp), and on seeds of grasses, sedges, pondweed, and crowberry. They take these foods rapidly with the bill much as dabbling ducks do, seizing larger items and straining water through the bill to take smaller ones. Most prey is taken while “dabbling” or “tipping up,” submerging the head and breast underwater to reach prey near the bottom of shallow ponds. During the rest of the year, they eat few insects or seeds but a great variety of marine animal prey, mostly mollusks and small crustaceans, but also bristleworms (polychaetes), marine annelid (segmented) worms, sand dollars and sea stars, spoon worms (Echiura), and brachiopods. At their stopover sites, and on the wintering grounds, Steller’s Eiders frequently forage in beds of eelgrass, sea lettuce, or brown seaweed, where they dabble or “graze” but also tip up and dive. These algae beds abound in prey: mollusks, marine worms, echinoderms, snails, fish, and tiny crustaceans, especially amphipods and aquatic sowbugs (isopods). Birds molting their flight feathers in July­–August feed most heavily on blue mussels, but once their new feathers have grown in, they tend to consume more amphipods and tiny clams. Their diet also includes some foraminifera, which are tiny one-celled organisms that mostly live on the sea floor. When foraging in deeper water, Steller’s Eiders dive, opening the wings prior to diving, and pursue prey while swimming. They use the feet for swimming but may also use the wings for maneuvering. They take some prey from the water column and some from the sea floor. Large flocks may dive in unison, often while arranged in a long line.

Back to top

Nesting

Nest Placement

Nest Ground

Females select nest sites on raised ground in marshy tundra, often a hummock or small ridge with some small birch or willow as well as moss, lichen, and grasses. The nest site is usually near one or more small ponds. Most nests are near the coast, although some Spectacled Eiders may nest as much as 90 miles from the coast.

Nest Description

Females construct the nest, a large, soft bowl of grasses, sedges, moss, weeds, and lichens. Around the time she lays the third egg, she typically adds down feathers plucked from her breast. Nests average about 14.6 inches across and 7.7 inches tall, with interior cup 5.7 inches across and 3.7 inches deep.

Nesting Facts

Egg Description:

Olive-buff to brownish-orange.

Condition at Hatching:

Downy and eyes open. Feed themselves immediately.

Back to top

Behavior

Behavior Surface Dive

Like most diving ducks, Steller’s Eiders court in groups, with up to 7 males gathering around a female to vie for attention. These courting parties become active on the wintering grounds and often continue on the breeding grounds. These courting groups swim around coastal areas and tundra lakes rather quickly, often rising up in flight in a tight group, following the female. Males signal aggression to each other by rapidly raising the bill several times in quick succession. The male’s courtship display is a series of moves performed in a specific order: he stretches his bill and tail skyward; shakes; swims toward the female while turning the head side to side; raises up; and then swims away from the female, again turning the head side to side. Males display in silence. A receptive female signals approval by rapidly raising the bill several times and sometimes dipping the bill into the water or stretching the body upward. Once partnered, the male displays to the female in a manner similar to scoters and goldeneyes: dipping the bill, preening the back and wings, and shaking and turning the head. Both male and female respond aggressively to unpaired birds, lifting the head, lunging, and sometimes chasing out the intruder on foot or in flight. The female alone incubates the eggs. The male may guard her for 2 weeks before departing the area, leaving the female to tend the young. The female usually keeps the young near the nest area as they develop. Once young have fledged, the females and young move in flocks toward the coast and eventually to molt-migration sites where they spend the late summer before moving to wintering grounds. Steller’s Eiders form flocks for most of the year but usually do not mix with other waterfowl or seabirds (adult males sometimes join flocks of Spectacled Eiders).

Back to top

Conservation

Conservation Red Watch List

Based on data from both wintering and breeding grounds, Steller’s Eider populations are declining. Partners in Flight estimated a global breeding population of 93,000 in 2017, compared with estimates of 400,000 to 500,000 in the 1960s. Partners in Flight rates the species an 18 out of 20 on the Continental Concern Score and includes it on the Red Watch List, indicating their highest category of concern. Among conservation problems for this species are overfishing, petroleum exploration and production, oil spills, entrapment in lost and discarded fishing gear, and possibly hunting and lead poisoning (from lead shot).

Back to top

Credits

Fredrickson, Leigh H. (2001). Steller's Eider (Polysticta stelleri), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Lutmerding, J. A. and A. S. Love. (2019). Longevity records of North American birds. Version 1019 Patuxent Wildlife Research Center, Bird Banding Laboratory 2019.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

Back to top