King Eider Life History

Habitat

Habitat Oceans

King Eiders nest in arctic tundra, both wet and dry, usually not far from water, whether interior lakes or the ocean coast. Common plants in such habitats include purple saxifrage, crowberry, bearberry, Labrador tea, dwarf birch, arctic willow, pendant grass, and various sedges. They raise young in both saltwater and freshwater environments, and once the young fledge, all move to saltwater. In western North America, many gather in the western Beaufort Sea, where they feed in the rich waters off Russia, more than 10 miles from land. Adults undergo a molt in this area. In eastern North America, King Eiders gather after breeding to molt in waters off Disko Island (western Greenland) and Baffin Island, Nunavut, Canada, in fjords where prey is also plentiful. In fall, King Eiders move toward wintering areas, usually defined by the southern edge of sea ice or in large open-water areas (called “polynyas”) in the ice; some move around to different areas in winter, while others stay in one area for the entire season. Eastern birds also winter in Hudson Bay, and small numbers (up to 100) have sometimes wintered in the Great Lakes, especially Lake Ontario. King Eiders usually winter farther from land, and over deeper water, than Common Eiders. In spring, King Eiders follow gaps in the sea ice toward the nesting grounds, feeding and courting in polynyas and often crossing large expanses of ice to reach nesting grounds in April and May.

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Food

Food Aquatic invertebrates

At sea, King Eiders eat mostly shellfish, crustaceans, and algae. On land, they eat insects and plants. When at sea, King Eiders forage mostly by diving for prey, sometimes to depths of 180 feet but usually much less deeply. They feed alone or in flocks, with large numbers of birds often diving simultaneously. They take prey from the bottom, from the underside of sea ice, and from the water column. They eat a variety of shellfish, crustaceans, echinoderms (sea urchins, starfish), and algae (seaweed), which they capture with the bill and often consume when still underwater. When nesting on land, King Eiders eat mostly insects and plant matter. Here they forage in shallow freshwater environments by tipping up (submerging the front half of the body to reach food at the bottom), sieving (straining small prey out of water, with bill mostly closed), and probing for prey in shallows. In marine environments, their known prey items are daisy brittle star, green sea urchin, sugar starfish, sand dollar, sea snails, blue mussel, discord mussel, northern horsemussel, Icelandic scallop, Greenland cockle, blunt gaper (a clam), whitecap limpet, arctic lyre crab, great spider crab, and eggs of fish such as sculpin and lumpfish. In addition, they eat a remarkable variety of other species of amphipods, bivalves, hermit crabs, shrimp, barnacles, sea snails, sea anemones, sea slugs, sea squirts, starfish, marine worms, bryozoans, hydroids, and algae. In breeding areas, they consume large quantities of insects and their larvae, including beetles, water bugs, caddisflies, stoneflies, blowflies, midges, bees, and wasps, and they also eat marine worms, isopods, water fleas (tiny crustaceans), fairy shrimp, and tadpole shrimp. Some King Eiders also consume eelgrass, wigeon grass, buttercups, pendant grass, sedges, bur reeds, and aquatic mosses of many species. In the Great Lakes, King Eiders often eat introduced zebra mussels.

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Nesting

Nest Placement

Nest Ground

Male and female search for nest sites together, and the female the final selection. Nests are in a depression in tundra landscape, often near a rock or a hummock or ridge, usually near water, and always concealed by low vegetation.

Nest Description

The female begins to lay eggs, then deepens the nest scrape and begins to line it with vegetation from the immediate vicinity. After laying the third or fourth egg, she adds her own down to the nest, which measures on average about 10 inches across.

Nesting Facts

Clutch Size:2-7 eggs
Egg Description:

Olive or olive-buff.

Condition at Hatching:

Covered in down and able to leave the nest soon after hatching.

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Behavior

Behavior Surface Dive

King Eiders are strong fliers and excellent divers, probably diving to greater depths than other duck species. They swim underwater using their feet but often open their wings while underwater. Males court females from late winter into spring, with ritualized wing flapping, neck stretching, head turning, and calling. Females respond by dipping the bill to the water, bathing, preening, flapping their wings, and moving the head, especially raising the bill. Pair bonds are often established before or during spring migration. Unpaired males arrive in breeding areas earlier than females. Even during egg laying, males do not leave the side of their mates (except on occasion, to mate with other females). Both sexes may be aggressive toward other King Eiders at this time, chasing them, performing threat displays (most of which look similar to courtship), and even raising the modified shoulder feathers that look like twin black sails on the back. Generally, King Eiders are solitary nesters and do not defend a nesting territory (or do not need to). In some places, nests are close together, similar to Common Eider colonies, but this is uncommon. Male and female search out the nest site by flying over the tundra. The female selects the nest site and builds the nest as she lays eggs. Males guard their mates during egg laying but depart the area once the eggs are laid. Males then move toward molting areas at sea as the females incubate and then raise the young. After the young have fledged, family groups gather in marine areas and then migrate toward molting grounds. After molting, most King Eiders then move to different wintering grounds, also at sea. Young birds typically remain at sea during their first summer, as they do not breed in their first year. Over the course of a year, a King Eider may cover more than 9,000 miles.

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Conservation

Conservation Low Concern

King Eiders nest in very remote areas, so information about their populations and population trends is very limited. However, in recent decades, there are some indications of declines in western North America. Partners in Flight estimates a global breeding population of 800,000 and rates the species a 12 out of 20 on the Continental Concern Scale, indicating a species of low conservation concern. This species is still heavily hunted in Greenland, Alaska, Russia, and Canada (tens of thousands per year), but the impacts of hunting on the population have not been studied. Oil and gas development, oil spills, and modification of tundra habitats would likely have a negative impact on populations. Climate change, which is already showing myriad effects in arctic ecosystems, is likely the chief conservation concern for this species.

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Credits

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.

Powell, Abby N. and Robert S. Suydam. (2012). King Eider (Somateria spectabilis), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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

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