Eider Duck

A big, lethargic, heavy-bodied duck of northern coastlines. Often seen floating offshore in flocks of up to several thousand birds. Sociable in breeding season also, and often nests in colonies. Eider down, famous for its insulating qualities, is used in large amounts in the nest lining of these ducks, helping to keep the eggs warm in frigid northern climates. In some places, such as Iceland, the down is harvested commercially at coastal 'eider farms,' where the wild birds are encouraged to nest in sheltered nooks built for them.