Canvasback Life History

Habitat

Habitat Lakes and Ponds

Canvasbacks breed in small lakes, deep-water marshes, bays, and ponds. They tend toward waters with a dense border of cattails, rushes, and reed grass, but in the boreal forest they use open marshes. During migration and on the wintering grounds, Canvasbacks use marine and freshwater areas including estuaries, lagoons, rivers, ponds, marshes, lakes, and occasionally flooded agricultural fields.

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Food

Food Plants

Canvasbacks are omnivores, eating everything from seeds to plant tubers and from mussels to insects. During the breeding season they eat both plant and animal foods, but during migration and winter they primarily eat rhizomes and tubers from aquatic plants. Canvasbacks dive straight down to depths of around 7 feet to extract pieces of aquatic plants with their bill. Other food is taken from or just below the surface of the water.

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Nesting

Nest Placement

Nest Floating

Female Canvasbacks select the nest spot, typically in shallow wetlands with cattails, rushes, sedges, and reeds. The nest is most frequently built over water, but sometimes on land.

Nest Description

Female Canvasbacks build a large bulky platform of sedges, reeds, cattails, and rushes. Females loosely weave the material together and attach it to emergent stalks of vegetation, such that the nest floats on the water. Many nests are also covered from above by a canopy of plant stalks. Females continue to add material and down feathers to the nest for the first 10 days of incubation.

Nesting Facts
Clutch Size:5-11 eggs
Number of Broods:1 brood
Egg Length:2.4-2.6 in (6-6.7 cm)
Egg Width:1.8-1.7 in (4.5-4.4 cm)
Incubation Period:24-29 days
Egg Description:Greenish drab.
Condition at Hatching:Covered in down and able to leave the nest soon after hatching.
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Behavior

Behavior Surface Dive

Canvasbacks are diving ducks at home in the water, seldom going ashore to dry land. They sleep on the water with their bill tucked under the wing, and they nest on floating mats of vegetation. To get airborne Canvasbacks need a running start, but once in the air they are strong and fast fliers, clocking airspeeds of up to 56 miles per hour. Canvasbacks are social outside of the breeding season; they gather in large rafts by the thousands to tens of thousands. Only when winter food is scarce or clumped do they defend foraging areas against other Canvasbacks. During spring and early in the breeding season, they act more aggressively. Threat displays include putting the bill in the water or on the chest, jabbing, pumping the head, or chasing. Pairs begin forming during spring migration and continue on the breeding grounds. Courting male ducks gather around one female, assessing each other with a series of head movements until the female chooses one of them. Males stretch their necks, lower their heads while giving a coughing sound, and toss their head all the way back until it reaches the top of the back. Females stretch their necks and raise and lower their head to signal acceptance of a male. About halfway through incubation, males move to large fresh and brackish wetlands in central and western Canada to molt before migrating south in the fall. During this flightless period, males stay away from the shore, feeding on submerged vegetation and resting on islands. Females continue to incubate and feed hatchlings until it is time to migrate south.

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Conservation

Conservation Low Concern

Canvasback populations have fluctuated widely since the 1950s. Low numbers in the 1980s put the Canvasback on species of special concern lists, but numbers increased greatly in the 1990s. The North American Breeding Bird Survey suggests that the population has been stable from 1966 through 2015. In 2017, the U.S. Fish and Wildlife Service estimated the U.S. population at around 700,000 individuals. Partners in Flight estimated the global breeding population at 670,000. The species rates a 10 out of 20 on the Continental Concern Score, which means it is not on the Partners in Flight Watch List and is a species of low conservation concern. Fluctuations in numbers are likely due to wetland loss and to changes in water levels that reduce the number of available nest sites. The suggestion is that Canvasbacks did well in wet years and poorly in dry years. In the Prairie Provinces in Canada around 40% of original wetlands were lost between 1951 and 1981. In North and South Dakota 3.6 million acres of wetlands have been lost and another 3.6 million were lost in Minnesota. Loss of wild celery, a primary food source, due to pollution, siltation, and eutrophication also made some areas useless for Canvasbacks; their migration routes and wintering sites changed during the last 40 years as a result. Hunting may also contribute to fluctuations as harvest limits have changed over the last 3 decades. The U.S. Fish and Wildlife Service manages duck hunting and limits the number of individuals hunters can take every year based on population size. From 2012–2106, hunters took on average 114,495 Canvasback annually.

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Credits

Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.

Lutmerding, J. A. and A. S. Love (2017). Longevity records of North American birds. Version 2017.1. Patuxent Wildlife Research Center, Bird Banding Laboratory, Laurel, MD, USA.

Mowbray, Thomas B. 2002. Canvasback (Aythya valisineria), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Raftovich, R. V., S. C. Chandler and K. A. Wilkins. (2015). Migratory bird hunting activity and harvest during the 2013-14 and 2014-15 hunting seasons. U.S. Fish and Wildlife Service, Laurel, Maryland, USA.

Raftovich, R. V., S. C. Chandler, and K. A. Wilkins. (2014). Migratory bird hunting activity during the 2012-2013 and 2013-2014 hunting seasons. U.S. Fish and Wildlife Service, Laurel, Maryland, USA.

Raftovich, R. V., S. C. Chandler, and K. A. Wilkins. (2016). Migratory bird hunting activity during the 2014-15 and 2015-16 hunting seasons. U.S. Fish and Wildlife Service, Laurel, Maryland, USA.

Raftovich, R. V., S. C. Chandler, and K. K. Fleming. (2017). Migratory bird hunting activity during the 2015-16 and 2016-17 hunting seasons. U.S. Fish and Wildlife Service, Laurel, Maryland, USA.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski, Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley guide to birds, second edition. Alfred A. Knopf, New York, USA.

U.S. Fish and Wildlife Service. (2017). Waterfowl Population Status, 2017. U.S. Department of Interior, Washington, D.C. USA.

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