Lesser scaup Aythya affinis

Identification Tips:

Adult male alternate:

Adult male basic:

Adult female:

Similar species:

Adult male Ring-necked Duck similar in alternate plumage but has quite different bill pattern, black back, grayer flanks and vertical white finger just behind black breast. Greater Scaup is very similar but has a more rounded head, larger bill, dark-tipped white primaries and secondaries, and glossy, greenish head as an adult male in alternate plumage. Female Greater Scaup has more rounded head, a broader bill, and more white flight feathers, and frequently has a distinct pale spot behind eye on side of head.