The "Lesser Scaup" is similar to the "Greater Scaup", except that his crown is higher and forehead steeper, giving it a more angular appearance. The former diving duck's head is a glossy green, rather than purple. This bird has a dark breast and tail feathers. Drakes have a bright yellow iris. The Lesser is colloquially known as the "Little Bluebill" or "Broadbill" because of its distinctive blue bill. The origin of the name 'scaup' may stem from the birds' preference for feeding on scalp - the Scottish word for clams, oysters, and mussels, however, some credit the female's discordant scaup call. "Lesser Scaup" forage mainly by sifting through the bottom mud, usually after diving and swimming underwater, occasionally by dabbling without diving.
The female "Lesser Scaup" is dark brown with a small, white face patch and white band at the base of her bill, and is often lighter in the ear region. Her iris is orange or amber.
In flight, their white wing stipe appears short, extending about one-half of the wing's length.
Breeding begins in May, but most birds nest only in June, later than usual for North American waterfowl. Breeding grounds are located from interior Alaska and northern Canada south to Colorado and Iowa, occasionally farther east.
Calls or song.
These birds are not very vocal, at least compared to dabbling ducks. Hens give the namesake discordant "scaup", "scaup" call and vocalize more often than the Greater Scaup, particularly during flight, but their call is weaker, a guttural "brrtt, brrtt". In courtship drakes produce weak whistles.
Population and distribution.
Found in large flocks on lakes and salt water inlets, "Lesser Scaup" winters along all three coasts.
The nest is a shallow depression, scraped in the ground and lined with plants and some down feathers. Nine to twelve dark olive-buff eggs are laid in it, some distance from the edge of the water.