The common eider is both the largest of the four eider species and the largest duck found in Europe and in North America. It measures 50 to 71 cm (20 to 28 in) in length, weighs 0.81 to 3.04 kg (1.8 to 6.7 lb) and spans 80–110 cm (31–43 in) across the wings. It is characterized by its bulky shape and large, wedge-shaped bill. The male is unmistakable, with its black and white plumage and green nape. The female is a brown bird, but can still be readily distinguished from all ducks, except other eider species, on the basis of size and head shape. The drake's display call is a strange almost human-like "ah-ooo," while the hen utters hoarse quacks. The species is often readily approachable.