The City Naturalist

Canvasback Duck

Article and Photos by Leslie Day

CANVASBACK DUCK (Aythya valisineria: aithya is Greek for seabird; valisneria comes from Vallisneria americana, the freshwater plant wild celery, which is one of the canasback's favorite food.)

OTHER NAMES: Bullneck, can, canard cheval, canny, canvas, gray duck, hickory-quaker, horse-duck, red-headed bullneck, sheldrake, and whiteback.

One of the largest North American diving ducks, the canvasback gets its name from its pale gray back and white sides which are delicately dotted and lined in a wavelike pattern resembling canvas fabric. Both males and females have long, sloping foreheads that in profile show a continuous line with the long, dark wedge-shaped bill. The male, or drake, has a rust-red head, black breast and rear, and a gray-white back. The female has a gray-white back, and a brown head and neck. Their eyes are like red rubies.

FEEDING HABITS: The canvasback dives for its food, arching its bill straight up, then down as it plunges below the water where it digs up mollusks. (Swans and mallard ducks also dabble for mollusks here in the Hudson River.) Canvasbacks also eat roots, tubers, the basal parts of bottom plants, aquatic insects and small fish. Staple foods in the warm months are pondweeds, wild celery, seeds of wild rice and other grasses, sedges and various parts of water lilies. Because canvasbacks strain many seeds with their bill out of bottom mud, they ingest much lead shot and are especially affected by lead poisoning.

The canvasback is an extremely wary duck, which gathers together in rafts of sometimes hundreds of individuals. They dive quickly in shallow water (3-12ft) and sometimes in deeper water (20-30ft.), then bob up to the surface like little bars of soap. They feed in the morning and evening and rest in between, their bills tucked under their back feathers.

HABITAT: Canvasbacks nest on marshes. They often spend winters on lakes, bays, and estuaries, such as the Hudson. Although they breed mainly in the West, each winter large flocks migrate east to winter on the Great Lakes and along the Atlantic Coast. In recent years their numbers have declined drastically, chiefly because of the draining of large marshes and "pot holes" in the midwest, which are their breeding grounds.

RANGE: Canvasback nests are found in freshwater marshes and pothole country from Alaska to Manitoba, south to Minnesota, Nebraska and California. They spend winters from British Columbia and Massachusetts south to the Gulf coast and to Central America.

Here at the Boat Basin the Canvasbacks show up every January. They arrive in very large flocks and stay together. When we approach them to get a closer look they will quickly swim away. Even though they can be seen here swimming near the Mallards, they do not usually mix with other ducks. However, there is one male canvasback that winters here with a group of mallards and swims to our boats for food. He has been nicknamed "Divin' Ivan" by one of our neighbors.

FLIGHT: Flocks travel at great speeds, in large V-shaped formations. They are among the fastest flyers, capable of flying up to 72 m.p.h.

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