May. Breeding range includes the eastern coastline of North America starting from northern Labrador, Newfoundland to the southern coastline of the United States. One of the largest ducks, the Common Eider is 24 inches in average size. The head of a mature male is mostly white, with a black mask flaring back over the eyes and a long sloping beak with a spade-like hook at the tip. The back of the mature male is white. Tail, wingtips, and wing flaps are black.
Females are similar to males in shape, but are light brown overall, with a white beak.
Female flanks are brown with mottled black stripes. Immature males are dark brown, with a white breast and pale-coloured head. The Common Eider is mainly found along rocky island coastlines toward the open sea. Nests are usually found on islands, and the upbringing of offspring is communally shared among females. One oddity that may be an unique characteristic is the use of their own feathers to construct nests.