Scientific name: Somateria mollissima (Linnaeus, 1758)
Bird group: Ducks
Field characters. 50-71 cm. A large, long-headed, bulky sea-duck. Male is the only duck with black belly and white back; breast white, tinted pinkish; head white with black crown; green patches on the sides of the head and nape; white patch on sides of rump. Bulky in flight, with short, thick neck and entirely white forewing, contrasting with black quills. Bill with long triangular profile continued in almost straight line by that of flat forehead; olive-grey, with yellow or green tinge to base. Male in eclipse highly variable, essentially blackish brown except for white patch on sides and white on wing. Female is warm brown, streaked and barred with blackish; in flight with two buffish or white wing-bars. Juvenile resembles female, but brown duller. Young birds slowly attain adult plumage, and males therefore have irregular piebald appearance.
Voice. Male utters a low, crooning sound during courtship "ah-oo"; female utters hoarse, grating "k-r-r-r".
Distribution. Common in northern Europe and Iceland.
Habitat. Breeds on low-lying coasts, islands, skerries and reefs with rocky or sandy shores. Mainly on sea outside the breeding season.
Food. Dives for bottom-living animals, mainly molluscs and, to a lesser extent, crustaceans and echinoderms. In small quantities it takes also fish, sea-anemones, cuttlefish, insects and polychaetes. On the breeding grounds, incubating females take also berries, green algae, leaves, and seeds. Prey is swallowed under water or brought to the surface and shaken in order to separate mussel clumps.
Eggs. Often with oil stains, sometimes unmarked or with dark green markings. Ground colour greenish-grey/green/buff (sometimes)/blue (seldom). Texture smooth, not glossy. Shape subelliptical/long subelliptical. Size 77 x 52 mm (68-88 x 47-57), weight 109 g (87-127).