Bird Lore: Canvasback

The Canvasback is a diving duck, known for its slender, sloping facial profile. It winters throughout much of Washington on lakes, salt bays, and estuaries. It can occasionally be seen in Edmonds. It has been seen a few times at the Edmonds marsh and several times along the waterfront where it is usually flying by. One of the more reliable places to see the Canvasback, near Edmonds, is at the north end of Lake Washington. The dock at Kenmore’s Log Boom Park can be a good viewing site for this duck.

The Canvasback mostly dives for its food, usually in water only a few feet deep. Sometimes it stirs up bottom sediment with its feet and then upends to feed. It forages on the leaves, roots, and seeds of aquatic plants such as pondweeds, sedges, grasses, and wild celery. It will also eat some mollusks, insects, and some small fish. Its scientific species name, valisineria, is derived from Vallisneria americana (common celery or water-celery), its preferred food during the nonbreeding season.

Canvasback breeding grounds are shallow freshwater marshes, mostly in northern Canada and central Alaska. Pair formation begins in spring, along the way to their breeding grounds and continues once they arrive. Courting males gather around one female and engage in a series of head movements until the female makes her choice. The males stretch their necks, make coughing sounds while lowering their heads, and then toss their heads backwards until they touch the tops of their backs. The female stretches her neck and raises and lowers her head to signal acceptance of a male.

The female builds a bulky basket-like nest of dead vegetation and lined with down. It is located in a stand of dense vegetation above shallow water. She incubates her 7-12 eggs for between 23-28 days. She sometimes lays eggs in the nest of another Canvasback. And both Redheads and Ruddy Ducks are known to lay eggs in Canvasback nests. The female leads her young to open water several hours after they have hatched. The young feed themselves but the female remains with them for several weeks. She leaves before the young have fledged because they are not capable of flight until 60-70 days after hatching.

The Canvasback migrates late in fall and early in spring. Migrating flocks fly high, usually in a V-formation. It is a strong flier that can reach speeds of up to 70 mph. The oldest known Canvasback was a male at least 22 years and 7 months of age when it was shot in California in 1991. It had been banded in that state in 1969. There is no specific collective noun for the Canvasback, but some that apply to any group of ducks include brace, flush, paddling, raft, and team.

The global population of the Canvasback has fluctuated greatly since the 1950s. Lows numbers in the 1980s, which were cause for concern, turned around in the 1990s with a large population increase. The Canvasback remains vulnerable to the ongoing loss of wetlands. The current estimated population is about 670,000 birds. Between 2012 and 2016, U.S. hunters took about 114,000 Canvasbacks each year.

There are few recordings of the Canvasback and they are not high quality. This one gives a sense of the Canvasback’s call:

— By Carol Riddell

Carol Riddell manages the bird education displays, on behalf of Pilchuck Audubon Society and Edmonds Parks & Recreation, at the Olympic Beach Visitor Station.

Leave a Reply

Your email address will not be published. Required fields are marked *