Description

The Common Eider (Somateria mollissima) is the largest duck in the Northern Hemisphere, widely distributed across Arctic and subarctic coasts of the North Atlantic and North Pacific. Adult males are striking—white, black, and green—with a sloping forehead and long wedge-shaped bill. Females are camouflaged in barred brown plumage to blend into rocky nesting islands.

Eiders are powerful divers, feeding mainly on benthic invertebrates such as mussels, clams, sea urchins, and crabs. They routinely dive 20–40 m, using strong legs and dense bones for ballast. Adults typically measure 50–71 cm long and weigh 1.8–3.0 kg.

Their down is among the softest known natural insulators. Females pluck their own breast feathers to line the nest, producing the famous “eiderdown.” Colonies often number thousands, located on isolated islands where predators are scarce.