eider

An eider is one of several large sea ducks in the genus Somateria, found mainly in Arctic and subarctic coastal waters. The most familiar species is the common eider (Somateria mollissima), but the group includes others such as the king eider (S. spectabilis) and the spectacled eider (S. fischeri). Eiders are among the larger northern ducks and are notable for their diving prowess and, in breeding plumage, for striking coloration in males.

Eiders feed primarily by diving beneath the surface to forage for soft-bottom invertebrates. Their diet consists largely of mollusks (especially bivalves), crustaceans, and occasionally small fish. They prefer coastal areas such as bays, tidal flats, and fjords, and they form large flocks outside the breeding season.

Breeding occurs along Arctic and subarctic coasts and on offshore islands. The female builds a shallow ground nest near the shore and lays a clutch of typically four to six eggs. Incubation lasts roughly three weeks; ducklings are precocial and soon leave the nest to follow the mother to the water, where they grow on a diet of invertebrates.

Eiderdown, the soft underfeathers of the birds, has long been valued for insulation and is gathered from nests after breeding. In many regions, down harvesting is regulated to protect populations.

Conservation status varies by species and region. Some populations are stable or increasing, while others, such as the spectacled eider, have faced declines due to habitat loss, predation, and pollution. Climate change and oil spills remain ongoing concerns for Arctic coastal ecosystems.