King Eider (Somateria spectabilis)

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Image of a King Eider in its natural habitat
Birds Eider

Introduction

The King Eider (Somateria spectabilis) is a large Arctic sea duck with a circumpolar breeding distribution. It nests in high-latitude tundra across North America, Greenland, northern Europe and Siberia, then migrates to ice-free coastal waters and polynyas for the non-breeding season. Its boldly patterned males, specialised diving ability and association with some of the world’s most remote marine environments make it a distinctive member of the duck family, Anatidae.

Physical Description

King Eiders are heavy-bodied ducks measuring approximately 47–64 centimetres in length and weighing about 1.2–2.1 kilograms. They have a short, thick neck, a rounded head and a relatively short, heavy bill.

Adult males are conspicuous. The head and neck are pale blue-grey and green, with a large orange-yellow frontal shield above the bright orange-red bill. The breast and much of the underparts are black, while the back, flanks and parts of the wings are white. The green cheek patch and prominent frontal shield are particularly useful identification features.

Females are smaller-looking and much less colourful. Their plumage is rich rusty brown, intricately barred and mottled with black, providing camouflage during nesting. They have a dark bill and a smoother slope from the forehead to the bill than males. Immature males are generally brown and may show a paler chest and developing orange on the bill before acquiring adult plumage.

King Eiders have dense insulating plumage and substantial fat reserves, adaptations that help them withstand cold marine conditions. Their broad, strong feet and compact bodies also support powerful diving and swimming.

Range and Habitat

The King Eider has a circumpolar distribution across the Arctic and sub-Arctic. Breeding populations occur in Alaska, northern Canada, Greenland, Scandinavia and northern Russia. It is one of the most northerly nesting sea ducks.

During the breeding season, King Eiders use wet and dry tundra, coastal plains, islands and inland lakes or ponds. Nests are usually placed close to water in low vegetation, often near a hummock, ridge or rock that provides some shelter and concealment.

After breeding, adults gather at coastal moulting areas, fjords, shallow marine habitats and offshore waters. They generally winter near the southern edge of the pack ice, in open-water areas within the ice known as polynyas, and along northern Atlantic and Pacific coastlines. Some eastern birds winter in Hudson Bay, while small numbers may reach farther south, including the Great Lakes.

The species is migratory, although routes and wintering areas differ between broad western and eastern populations. Individuals often follow openings in the sea ice during spring migration and may cross extensive areas of ice between feeding and breeding sites.

Behaviour and Diet

King Eiders are social outside the breeding season and commonly rest, migrate and forage in flocks. They may associate with other sea ducks, particularly in coastal waters and at migration stopovers.

At sea, they are strong divers that obtain much of their food from the seabed, the water column and the underside of sea ice. They commonly feed at depths of around 20 metres, although dives may reach approximately 55 metres in suitable conditions. Their diet includes molluscs, crustaceans, echinoderms, marine worms, other aquatic invertebrates and algae. Important prey can include mussels, clams, sea snails, sea urchins, starfish, crabs and shrimp.

In breeding areas, King Eiders also forage in shallow freshwater habitats. They take aquatic insects and their larvae, small crustaceans, molluscs, worms, tadpole shrimp and plant material. Feeding methods include diving, probing sediment, tipping up and sieving small prey from the water.

Breeding begins in late spring or early summer. The female selects a concealed ground nest near water, lays a clutch commonly containing four or five eggs, and lines the nest with vegetation and down. Clutches may range from three to seven eggs. The female incubates the eggs alone for about 22–24 days. The ducklings are precocial, leaving the nest soon after hatching and feeding themselves under the female’s guidance. They develop rapidly and are capable of flight at roughly seven weeks, although timing varies with conditions.

Identification Tips

Look for the following combination of features:

  • A large, compact sea duck with a rounded head and short, heavy bill.
  • In adult males, a pale blue-green head, green cheeks, an orange-yellow frontal shield, a bright orange-red bill and a black-and-white body.
  • In females, richly patterned rusty-brown plumage, a dark bill and a relatively smooth forehead-to-bill profile.
  • A preference for northern coastal waters, sea ice margins, tundra lakes and remote Arctic breeding habitats.
  • Deep diving and flocking behaviour, often alongside other sea ducks.

The male’s large frontal shield and colourful head distinguish it from most other eiders. Female King Eiders can be more difficult to separate from female Common Eiders, but the King Eider usually has a more compact appearance, a shorter and heavier bill, and a more rounded head. Care is needed because plumage varies with age, sex and moult.

Conservation Status

The King Eider is listed globally as Least Concern by the IUCN Red List. This category reflects its very large Arctic range, but it does not mean that all populations are stable or well monitored. Reliable long-term population data are limited because much of the species’ breeding and wintering range is remote.

Available monitoring indicates concern about declines in some regional populations, including Arctic populations assessed in Canada. Potential pressures include changes in sea-ice conditions, altered marine food supplies, severe weather during migration and breeding, starvation when ice restricts access to food, subsistence harvest, disturbance from increasing shipping and industrial activity, and pollution from oil spills or chronic discharges.

Conservation priorities include coordinated monitoring across the species’ international range, sustainable harvest management, protection of important breeding, moulting and wintering areas, and reduction of disturbance and pollution in Arctic marine habitats. Further research is needed to distinguish natural fluctuations from sustained population declines.

Frequently Asked Questions

Where does the King Eider live?

The King Eider breeds in Arctic tundra across Alaska, Canada, Greenland, northern Europe and Siberia. It winters mainly in northern coastal waters, near sea-ice margins and in open-water areas within the pack ice.

What does a King Eider look like?

The adult male has a pale blue-green head, green cheeks, an orange-yellow frontal shield, an orange-red bill and a black-and-white body. The female is brown, heavily mottled and cryptic, with a dark bill.

What does the King Eider eat?

It feeds mainly on marine invertebrates such as molluscs, crustaceans, sea urchins, starfish, worms and algae. In freshwater breeding areas, it also eats aquatic insects, small crustaceans and plant material.

How deep can a King Eider dive?

King Eiders commonly dive to about 20 metres, although recorded feeding dives can reach approximately 55 metres, depending on habitat and prey availability.

How many eggs does a King Eider lay?

A typical clutch contains four or five eggs, although clutches of three to seven eggs have been reported. The female incubates them alone for about 22–24 days.

Is the King Eider endangered?

The species is currently classified as Least Concern globally by the IUCN. However, some regional populations appear to have declined, and monitoring remains limited, so Arctic climate change, harvest, pollution, disturbance and changes in marine food supplies remain important conservation concerns.

References

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