White-winged Scoter Overview, All About Birds, Cornell Lab of Ornithology

Although the White-winged Scoter winters primarily along the coasts, small numbers winter on the eastern Great Lakes. Populations on the Great Lakes may have declined during the 1970s, but appear to be increasing in response to the invasion of the zebra mussel, a new and abundant food source.

The White-winged Scoter often nests in association with gull breeding colonies. Although the gulls would happily eat the eggs and chicks of the scoter, the dense vegetation where the scoter nests keeps them safe.

The White-winged Scoters found in North America and eastern Asia differ from those found in Europe in the structure of the bill and trachea of the male. The European "Velvet Scoter" male has only a slight swelling on the top of the bill, and the bill is yellow, not orange. The two forms sometimes are regarded as distinct species.