Common Name: Can
As masthead for Delta Waterfowl, the Canvasback has been called the “aristocrat of ducks”. Despite its elegant appearance, the Canvasback’s Latin name valisinerie is actually taken from wild celery (Vallisneria americana) which is a preferred food outside of the breeding season.
It is easy to identify the regal drake Canvasback as he surveys his domain while resting on a local wetland. In breeding season, drakes sport a chestnut-red head and neck with a thick black band encircling the upper body. The white back actually appears gray from fine black-brown vermiculations. They also have red eyes and gray-blue feet. Outside of breeding season, males have a duller cinnamon brown head and chest with a dusky gray back, sides and flanks.
Adult females are less colorful then their male counterpart. Hen Canvasbacks have a light brown head and neck that merges into a darker brown chest and foreback. Both males and females have a unique profile with a wedge-shaped head that slopes up from the tip of the bill to the back of the crown. Their neck is also longer then most other diving ducks. This profile is useful in distinguishing Canvasbacks from Redheads who have a shorter bill and a steep forehead.
In flight, Canvasbacks are one of the fastest flying of the larger ducks. They fly directly, without the dipping and weaving seen in Scaup and Ring-necks.
During breeding season, Canvasbacks choose small lakes, deep-water marshes, sheltered bays of large fresh water and alkali lakes, permanent and semi-permanent ponds, sloughs, potholes and shallow river impoundments. After the young hatch, hens rear them in the same habitat they used for nesting, usually moving them a short distance to more permanent water with open water, less cover and more submerged vegetation.
During molt, females and their broods generally stay in their breeding habitat while adult males move to lakes with large expanses of open water and abundant submerged vegetation.
In winter, Canvasbacks can be found in a range of habitats such as deep freshwater lakes, coastal brackish and salt-water estuaries, shallow bays and harbors, riverine deltas and deltaic splays. Predictability of food sources and the ability of the Canvasbacks to access that food generally determines habitat choice in winter.
Canvasbacks are diving ducks, finding their food underwater. They are omnivorous, meaning they eat both plant and animal material. The types of food they eat are heavily dependent on availability. In the winter and during migration they will eat mainly aquatic plant parts (winter buds, rhizomes and tubers), but if that is unavailable, they will also eat small clams and snails. During breeding season, they consume aquatic plants, but also eat things such as snails, caddisfly larvae and midge larvae.
Canvasback hens build their nests in emergent vegetation over water and occasionally on land. Nests are large and bulky, made of woven plant material and lined with down. One grayish olive or greenish drab egg is laid every day until there are about 7 to 8. It is not unusual to find that a Redhead hen has also added an egg or two to a Canvasback nest or, even more commonly, another Canvasback will lay her eggs in another’s nest. Incubation starts during the laying of the last 2 or 3 eggs and lasts 24 to 29 days.
Raccoons, skunks, crows and magpies are the major nest predators of Canvasbacks.
Once hatched, the hen will brood her ducklings for about 24 hours before moving them to large ponds with abundant submerged vegetation. Hens remain with their brood for different lengths of time, depending on the lateness of the season. Hens that laid early will stay with their brood until they are nearly ready to fly, but they will abandon late broods after 2 – 3 weeks.
Conservation and Management
The Canvasback is a federally protected migratory game bird in Canada, USA and Mexico. It was on the “Blue List” (species that may be of concern) from 1975 to 1981 and was a “Species of Concern” in 1982 and 1986. However, between 1994 and 1995 its breeding population increased to >770,000, well above 563,000, the long-term average set by the North American Waterfowl Management Plan. Estimates for 2003 put Canvasback numbers at 558,000, up 15% from 2002.
Sources of Information
Bellrose, F.C. 1976. Ducks, geese and swans of North America, 2nd edition. Stackpole Books, Pennsylvania.
Hochbaum, H.A. 1944. The Canvasback on a Prairie Marsh. University of Nebraska Press.
Mowbray, T.B. 2002. Canvasback (Aythya valisineria). In The Birds of North America, No. 659 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.