Somateria mollissima



This is a bulky sea duck that's slightly larger than the Mallard. Its body is fat with a short neck. It has a large head and a distinctive, wedge-shaped bill that forms a continuous line with its forehead. The sexes have dissimilar plumages. Males have mainly black underparts and white upperparts; he has a black cap and a lime green nape and his breast is tinged with pink. Females are brown with darker and more detailed barring and mottling; her long forehead makes her appear different from most other ducks. Juveniles appear similar to female adults, though they usually have a pale stripe above the eye; young males take 4 years to gain adult plumage. When flying, the male has big white patches on his wings and the female shows a dark speculum with thin white bars.


The Eider can be found around coasts of Scotland, northeast England and the northern coast of Ireland. Almost strictly a marine species, it prefers to live around rocky coasts and nests close to seashore. After the breeding season, the search for bountiful amounts of food leads them to estuaries and other sheltered coasts.


The Eider is a regular diver and is often submerged for a long time. It's a gregarious bird which socialises in groups in summer and forms larger flocks in winter. Its head droops in flight and it looks quite heavy; flocks often fly low over the water in line formations.


These birds get most of their food from the seabed. They eat shellfish and molluscs, and their primary prey is the blue mussel. Periwinkles, crabs, starfish and sea urchins are also part of the diet, and small fish when they can be caught without too much hassle.


Breeding begins in late April. Nests are usually built in hollows near the sea, in the shelter of rocks and vegetation, and they're often within colonies of Arctic Terns. Female lays 4-6 eggs and incubates them for 25-28; she doesn't feed regularly in that time. While she's laying, the male is protective, then he deserts during incubation. Young hatch and are able to swim and dive shortly afterwards. Communities of females unite to brood until young are independent (after 55 days and able to fly at 65 days).


British and Irish birds are fairly sedentary, not shifting far from breeding grounds. Migrants from the Baltic and the Netherlands arrive on the east coast of Britain in autumn. About 63 000 pairs breed in the UK and 1000 in Ireland; the UK winter population of about 80 000 individuals is decreasing.

Observation Tips

Eiders can be fairly tolerant of human observers; good views can be found in northern Britain. Nesting birds can be watched from surprisingly short distances on Farne Islands in Northumberland.


Though he is silent for most of the year, the male throws his head back to utter a cooing call when displaying: 'ah-whooo'.