Common Eider

Identification

The common eider is the largest of the four eider species, measuring 50 to 71 cm in body length with a wingspan of 80–110 cm. Its bulky shape and large, wedge-shaped bill are distinctive field marks. Males are unmistakable, displaying striking black and white plumage with a green nape, while females are brown birds that can be distinguished from other ducks by their size and characteristic head shape. The drake's display call is a strange, almost human-like "ah-ooo", while females utter hoarse quacks. The species is often readily approachable by observers.

Different subspecies show subtle plumage and bill colour variations. The nominate European and central Asian subspecies has a yellowish-green bill, while the North American dresseri subspecies displays a greenish-grey bill. The Arctic Atlantic and Arctic Pacific subspecies are distinguished by bright orange-yellow bills. These distinctions allow experienced birders to identify subspecies in the field.

Range & Habitat

The common eider is distributed over the northern coasts of Europe, North America, and eastern Siberia. It breeds in Arctic and some northern temperate regions, wintering somewhat farther south in temperate zones where it can form large flocks on coastal waters. Six subspecies are recognized, each with distinct breeding and wintering ranges. Notable populations breed in Greenland, Iceland, northeast Canada, the Faroe Islands, and northwest Eurasia, with some populations venturing into inland freshwater lakes in Switzerland.

A particularly famous eider colony lives on the Farne Islands in Northumberland, England, where about 1,000 pairs still nest every year. The species is generally abundant, with populations of about 1.5–2 million birds in both North America and Europe, and large but unknown numbers in eastern Siberia. However, some populations are small and declining, notably the isolated Crimean population in the Black Sea, which numbers only around 700–1,100 pairs and is of conservation concern.

Behaviour & Diet

Common eiders are diving ducks that feed primarily on crustaceans and molluscs, with mussels being a favoured food source. They swallow mussels whole, crushing the shells in their gizzard before excreting them. When eating crabs, eiders methodically remove all claws and legs before consuming the body. This specialized foraging behaviour makes them strictly marine feeders, though the invasive zebra mussel in Swiss lakes has allowed a small population to breed far inland since 1988.

Eiders breed in nests built close to the sea, lined with eiderdown plucked from the female's breast. This renowned soft and warm down has long been harvested for filling pillows and quilts. Though eiderdown harvesting has largely given way to down from domestic farm-geese and synthetic alternatives, the practice continues sustainably, as it can be done after the ducklings leave the nest with no harm to the birds.

Best Time & Places to See It

The common eider's migratory nature means timing depends on location. In breeding areas such as Greenland, Iceland, and the Canadian Arctic, the species is present during summer months. Winter offers excellent viewing opportunities on coastal waters of temperate zones where large flocks gather. The Farne Islands in Northumberland, England, are renowned for reliable eider viewing, with about 1,000 breeding pairs present during the breeding season. North Atlantic coasts, the Bering Sea, and the Aleutian Islands are also key locations depending on subspecies and season.

Photography Tips

The common eider's bulky form and striking plumage—particularly the males' bold black and white pattern with green nape—make it an attractive photographic subject. The species is often readily approachable, allowing photographers to achieve intimate images without excessive disturbance. Males are visually distinctive and photograph well in all lighting conditions, while females, though more subtle in colouration, present a challenge that rewards patient observation. Capturing the drake's dramatic display or documenting flocking behaviour on winter coastal waters offers diverse compositional opportunities.