Field identification tips: A diving duck that breeds in northwestern mountains, northwest Canada, and Alaska, the Lesser Scaup (Aythya affinis) is very simular to the Greater Scaup (Aythya marila). Adult males show a grayish finely barred back, white sides, a black breast, an irridescent dark head and golden eyes. Females are brown overall with a white spot between the bill and the eye. Immature males are similar to the adult males except the sides are smudged with gray. A. affinis differs from A. marila in the extent of white on the flight feathers, A. affinis showing white through the secondaries while on A. marila the band of white extends into the primaries. A. affinis also has a smaller black 'nail' at the tip of the bill, and more of a 'peaked' head instead of A. marila's rounded head.
Typical range: A. affinis breeds in the western mountains, the prairie pothole region of Canada, and Alaska, overwintering in the west coast and southern states, and south through Mexico and the Caribbean islands.
Habitat: A. affinis can be found in freshwater ponds and lakes, brackish water, coastal estuaries and bays. A. affinis is more likely in fresh water than A. marila.