This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the canvasback.
Open water has invited waterfowl back to area lakes. Some will stay until ice again forces their departure, but others like the canvasback will only stop for a while before traveling farther north for the summer. North America’s largest diving duck is named for the male’s clean, white back and sides, which reminded English settlers of canvas fabric.
The male’s white body contrasts with his maroon-colored head and thick neck. His sloped forehead, which ends in a long, dark bill, gives his head a distinctive triangular shape. Grayish-brown females share the same profile.
The canvasback rarely spends time on dry land, sleeping on water with head tucked, and typically building its nest over water on floating mats of vegetation. These ducks often dive to depths of around 7 feet to feed on submerged plants, but can also go as far as 30 feet. A favorite food is aquatic wild celery, the source of its species name, valisineria, and nearly the cause of its extinction.
Hunters found that celery in its diet gave a tasty flavor to this duck’s flesh. The introduction of more efficient shotguns and refrigeration after the Civil War resulted in a surge in commercial market hunting and a high demand for this bird on the menus of city restaurants. Protections given by the Migratory Bird Treaty Act in 1918 which outlawed uncontrolled hunting saved this and other bird species from extinction.
Most canvasbacks breed in the prairie pothole regions, an area of wetlands and grasslands that extends across five northern states and three Canadian provinces. These depressional wetlands which fill with snowmelt and rain in spring are known as “America’s Duck Factory.” According to Ducks Unlimited, this area is one of North America’s most threatened waterfowl habitats, with only 40 to 50 percent of the original wetlands remaining undrained today.
Last year a Supreme Court ruling severely reduced the protections on our country’s wetlands afforded by the Clean Water Act. Colorado’s lawmakers are currently considering legislation to restore these protections to Colorado’s wetlands.
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