Lesser Scaup

Aythya affinis

Description:

"The Lesser Scaup (Aythya affinis) is a small North American diving duck that migrates south as far as Central America in winter. The origin of the name scaup may stem from the bird's preference for feeding on scalp - the Scottish word for clams, oysters, and mussels, however, some give it credit to the female's discordant scaup call as the name's source. Lesser Scaup forage mainly by sifting through the bottom mud, usually after diving and swimming underwater, occasionally by dabbling without diving. They mainly eat mollusks such as mussels and clams, as well as seeds and other parts of aquatic plants like sedges and bulrushes (Cyperaceae), "pondweeds", Widgeon-grass (Ruppia cirrhosa), Wild Celery (Vallisneria americana) or wild rice (Zizania). In winter, but less so in summer, other aquatic animals – crustacean, insect and their larvae and small fishes – form an important part of their diet. It has been reported that both the Lesser and the Greater Scaup have shifted their traditional migration routes to take advantage of the presence of the Zebra Mussel (Dreissena polymorpha) in Lake Erie, which was accidentally introduced in the 1980s and has multiplied enormously. This may pose a risk to these birds because zebra mussels are efficient filter feeders and so accumulate environmental contaminants rapidly. They nest in a sheltered location on the ground near water, usually among thick vegetation such as sedges and bulrushes, sometimes in small loose groups and not rarely next to colonies of gulls or terns; several females may deposit eggs in a single nest. The drakes court the hens in the winter quarters; pairs form shortly before and during the spring migration. When nesting starts, the males aggregate while they moult into eclipse plumage, leaving the task of incubation and raising the young to the females alone."