Canvasback
Canvasback Temporal range:
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Male | |
Female with ducklings | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Anseriformes |
Family: | Anatidae |
Genus: | Aythya |
Species: | A. valisineria
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Binomial name | |
Aythya valisineria (Wilson, 1814)
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Synonyms | |
Aythya vallisneria (lapsus) |
The canvasback (Aythya valisineria) is a species of diving duck, the largest found in North America.
Taxonomy
Scottish-American naturalist Alexander Wilson described the canvasback in 1814. The genus name is derived from Greek aithuia, an unidentified seabird mentioned by authors, including Hesychius and Aristotle.[2] The species name valisineria comes from the wild celery Vallisneria americana, whose winter buds and rhizomes are the canvasback's preferred food during the nonbreeding period.[3] The celery genus is itself named for seventeenth century Italian botanist Antonio Vallisneri.[2]
The duck's common name is based on early European inhabitants of North America's assertion that its back was a canvas-like color.[4] In other languages it is just a white-backed duck; for example in French, morillon à dos blanc, or Spanish, pato lomo blanco.[5] In Mexico it is called pato coacoxtle.[6]
Description
It ranges from 48–56 cm (19–22 in) in length and weighs 862–1,600 g (1.900–3.527 lb), with a wingspan of 79–89 cm (31–35 in). It is the largest species in the genus Aythya, being similar in size to a mallard but with a heavier and more compact build than it. 191 males wintering in western New York averaged 1,252 g (2.760 lb) and 54 females there averaged 1,154 g (2.544 lb).[7] The canvasback has a distinctive wedge-shaped head and long graceful neck. The adult male (drake) has a black bill, a chestnut red head and neck, a black breast, a grayish back, black rump, and a blackish brown tail. The drake's sides, back, and belly are white with fine vermiculation resembling the weave of a canvas, which gave rise to the bird's common name.[8] The bill is blackish and the legs and feet are bluish-gray. The iris is bright red in the spring, but duller in the winter. The adult female (hen) also has a black bill, a light brown head and neck, grading into a darker brown chest and foreback. The sides, flanks, and back are grayish brown. The bill is blackish and the legs and feet are bluish-gray. Its sloping profile distinguishes it from other ducks.[8]
Breeding
The breeding habitat of the canvasback is in
It has a clutch size of approximately 5–11 eggs, which are greenish drab. The chicks are covered in down at hatching and able to leave the nest soon after.
Migration
The canvasback migrates through the
Diet
The canvasback feeds mainly by diving, sometimes dabbling, mostly eating seeds, buds, leaves, tubers, roots, snails, and insect larvae.[3] Besides its namesake, wild celery, the canvasback shows a preference for the tubers of sago pondweed, which can make up 100% of its diet at times.[10] The canvasback has large webbed feet adapted for diving and its bill helps it dig tubers from the substrate. In the late 1930s, studies showed that four-fifths of the food eaten by canvasbacks was plant material.[11]
In the early 1950s it was estimated that there were 225,000 canvasbacks wintering in the
Cuisine
Canvasback ducks were a particularly prestigious game dish in mid-19th-century America. They were rarely found on everyday menus, and often featured at banquets. They were generally sourced from Maryland and Chesapeake Bay, and their flavor was attributed to their diet of wild celery. By the end of the century, though, they had become "scarce, expensive, or unobtainable".[12]
Conservation
Populations have fluctuated widely. Low levels in the 1980s put the canvasback on lists of special concern, but numbers increased greatly in the 1990s.[14] The canvasback is particularly vulnerable to drought and wetland drainage on the prairies of North America.[8]
Many species of ducks, including the canvasback, are highly migratory, but are effectively conserved by protecting the places where they nest, even though they may be hunted away from their breeding grounds.[1] Protecting key feeding and breeding grounds is key for conserving many types of migratory birds.[citation needed]
References
- ^ . Retrieved 12 November 2021.
- ^ ISBN 978-1-4081-2501-4.
- ^ a b c d "Canvasback". All About Birds. Cornell Lab of Ornithology.
- ^ "Canvasback". Dictionary.com Unabridged (Online). n.d.
- ^ "Aythya valisineria". Avibase.
- ^ "Pato Coacoxtle". 15 December 2015.
- ISBN 978-1-4200-6444-5.
- ^ a b c d e f "Canvasback". Ducks Unlimited. Retrieved 23 November 2009.
- ISSN 0007-0335.
- ^ Flora of North America: Stuckenia pectinata
- ^ a b SAV… It’s What’s for Dinner, Developed by Martha Shaum, Aquatic Resources Education Program, Maryland Department of Natural Resources Archived April 19, 2011, at the Wayback Machine
- , pp. 36, 39
- ISBN 9781787695283, p. 59
- ^ Mowbray, T. B. (2002). "Canvasback (Aythya valisineria)". In Poole, A.; Gill, F. (eds.). The Birds of North America. Vol. 17. Philadelphia, PA: The Birds of North America, Inc.
External links
- Canvasback - Aythya valisineria - USGS Patuxent Bird Identification InfoCenter
- "Canvasback media". Internet Bird Collection.
- Canvasback photo gallery at VIREO (Drexel University)
- Interactive range map of Aythya valisineria at IUCN Red List maps
- Mowbray, Thomas B. (2020-03-04). Poole, Alan F; Gill, Frank B (eds.). "Canvasback (Aythya valisineria)". Birds of the World. S2CID 216414904. Retrieved 2021-04-20.