Canvasback Temporal range: | |
---|---|
Male | |
Female with ducklings | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Anseriformes |
Family: | Anatidae |
Genus: | Aythya |
Species: | A. valisineria |
Binomial name | |
Aythya valisineria (Wilson, 1814) | |
Breeding Migration Year-round Nonbreeding | |
Synonyms | |
Aythya vallisneria( lapsus ) |
The canvasback (Aythya valisineria) is a species of diving duck, the largest found in North America.
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]
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]
The breeding habitat of the canvasback is in North American prairie potholes. The bulky nest is built from vegetation in a marsh and lined with down. Loss of nesting habitat has caused populations to decline. The canvasback usually takes a new mate each year, pairing in late winter on ocean bays. [3] It prefers to nest over water on permanent prairie marshes surrounded by emergent vegetation, such as cattails and bulrushes, which provide protective cover. Other important breeding areas are the subarctic river deltas in Saskatchewan and the interior of Alaska. [8]
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. [3] The canvasback sometimes lays its eggs in other canvasback nests and redheads often parasitize canvasback nests. [8]
The canvasback migrates through the Mississippi Flyway to wintering grounds in the mid-Atlantic United States and the Lower Mississippi Alluvial Valley (LMAV), or the Pacific Flyway to wintering grounds along the coast of California. Historically, the Chesapeake Bay wintered the majority of canvasbacks, but with the recent loss of submerged aquatic vegetation (SAV) in the bay, their range has shifted south towards the LMAV. Brackish estuarine bays and marshes with abundant submergent vegetation and invertebrates are ideal wintering habitat for canvasbacks. [8] A small number of birds are also known to have crossed the Atlantic, with several sightings being recorded in the United Kingdom. In December 1996, a canvasback was observed in a quarry in Kent, which was followed by an additional sighting in Norfolk in January 1997. At least five more sightings have since been confirmed in England. [9]
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 Chesapeake Bay; this represented one-half of the entire North American population. By 1985, there were only 50,000 ducks wintering there, or one-tenth of the population. Canvasbacks were extensively hunted around the start of the 20th century, but federal hunting regulations now restrict their harvest, so hunting is ruled out as a cause for the decline. Scientists have now concluded that the decline in duck populations was due to the decline in sub-aquatic vegetation acreage. Today the population has stabilized and is even increasing slightly, although it is nowhere near previous levels. Studies have now shown that by the 1970s four-fifths of the ducks' diet was made up of Baltic Clams, which are very common in the Chesapeake Bay: the ducks have been able to adapt to the decline in sub-aquatic vegetation by changing their diet. Redheads, which also feed on the tubers of sub-aquatic vegetation, have not been able to adapt, and their population remains low. [11]
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]
Edith Wharton refers to canvasback with blackcurrant sauce as an especially luxurious dinner served in New York City in the 1870s. Canvasback duck was a canonical element, along with Terrapin à la Maryland, of the elegant "Maryland Feast" menu, an "elite standard... that lasted for decades". [13]
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 ]
The diving ducks, commonly called pochards or scaups, are a category of duck which feed by diving beneath the surface of the water. They are part of Anatidae, the diverse and very large family that includes ducks, geese, and swans.
The Eurasian teal, common teal, or Eurasian green-winged teal is a common and widespread duck that breeds in temperate Eurosiberia and migrates south in winter. The Eurasian teal is often called simply the teal due to being the only one of these small dabbling ducks in much of its range. The bird gives its name to the blue-green colour teal.
The redhead is a medium-sized diving duck. The scientific name is derived from Greek aithuia, an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin americana, of America. The redhead is 37 cm (15 in) long with an 84 cm (33 in) wingspan. Redhead weight ranges from 2.0 to 2.5 lbs, with males weighing an average of 2.4 lbs and females weighing an average of 2.1 lbs. It belongs to the genus Aythya, together with 11 other described species. The redhead and the common pochard form a sister group which together is sister to the canvasback.
The ring-necked duck is a diving duck from North America commonly found in freshwater ponds and lakes. The scientific name is derived from Greek aithuia, an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin collaris, "of the neck" from collum, "neck".
The American black duck is a large dabbling duck in the family Anatidae. It was described by William Brewster in 1902. It is the heaviest species in the genus Anas, weighing 720–1,640 g (1.59–3.62 lb) on average and measuring 54–59 cm (21–23 in) in length with an 88–95 cm (35–37 in) wingspan. It somewhat resembles the female and eclipse male mallard in coloration, but has a darker plumage. The male and female are generally similar in appearance, but the male's bill is yellow while the female's is dull green with dark marks on the upper mandible. It is native to eastern North America. During the breeding season, it is usually found in coastal and freshwater wetlands from Saskatchewan to the Atlantic in Canada and the Great Lakes and the Adirondacks in the United States. It is a partially migratory species, mostly wintering in the east-central United States, especially in coastal areas.
The blue-winged teal is a species of bird in the duck, goose, and swan family Anatidae. One of the smaller members of the dabbling duck group, it occurs in North America, where it breeds from southern Alaska to Nova Scotia, and south to northern Texas. It winters along the Pacific and Atlantic coasts and south into the Caribbean islands and Central America.
The common pochard, known simply as pochard in the United Kingdom, is a medium-sized diving duck in the family Anatidae. It is widespread across the Palearctic. It breeds primarily in the steppe regions of Scandinavia and Siberia, and winters further south and west.
The tufted duck is a small diving duck with a population of close to one million birds, found in northern Eurasia. The scientific name is derived from Ancient Greek aithuia, an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin fuligo 'soot' and gula 'throat'.
The ruddy duck is a duck from North America and one of the stiff-tailed ducks. The genus name is derived from Ancient Greek oxus, "sharp", and oura, "tail", and jamaicensis is "from Jamaica".
The greater scaup, just scaup in Europe or, colloquially, "bluebill" in North America, is a mid-sized diving duck, larger than the closely related lesser scaup. It spends the summer months breeding in Alaska, northern Canada, Siberia, and the northernmost reaches of Europe. During the winter, it migrates south to the coasts of North America, Europe, and Japan.
The lesser scaup is a small North American diving duck that migrates south as far as Central America in winter. It is colloquially known as the little bluebill or broadbill because of its distinctive blue bill. The origin of the name scaup may stem from the bird's preference for feeding on scalp—the Scottish word for clams, oysters, and mussels; however, some credit it to the female's discordant scaup call as the name's source. It is apparently a very close relative of the Holarctic greater scaup or "bluebill", with which it forms a superspecies. The scientific name is derived from Ancient Greek aithuia an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin, affinis "related to", from its resemblance to the greater scaup.
The ferruginous duck, also known as ferruginous pochard, common white-eye or white-eyed pochard, is a medium-sized diving duck from Eurosiberia. The scientific name is derived from Greek aithuia an unidentified seabird mentioned by authors including Hesychius and Aristotle, and nyrok, the Russian name for a duck.
The fulvous whistling duck or fulvous tree duck is a species of whistling duck that breeds across the world's tropical regions in much of Mexico and South America, the West Indies, the southern United States, sub-Saharan Africa and the Indian subcontinent. It has plumage that is mainly reddish brown, long legs and a long grey bill, and shows a distinctive white band across its black tail in flight. Like other members of its ancient lineage, it has a whistling call which is given in flight or on the ground. Its preferred habitat consists of wetlands with plentiful vegetation, including shallow lakes and paddy fields. The nest, built from plant material and unlined, is placed among dense vegetation or in a tree hole. The typical clutch is around ten whitish eggs. The breeding adults, which pair for life, take turns to incubate, and the eggs hatch in 24–29 days. The downy grey ducklings leave the nest within a day or so of hatching, but the parents continue to protect them until they fledge around nine weeks later.
The scaly-sided merganser or Chinese merganser is an endangered typical merganser. It lives in Manchuria and extreme Southeast Siberia, breeding in the north and wintering in the south.
The Madagascar pochard or Madagascan pochard is an extremely rare diving duck of the genus Aythya. Thought to be extinct in the late 1990s, specimens of the species were rediscovered at Lake Matsaborimena near Bemanevika in Madagascar in 2006. By 2017, a captive breeding program had produced a population of around 90 individuals. The birds were reintroduced to the wild in December 2018.
Baer's pochard is a diving duck found in eastern Asia. It is a resident bird in North and Central China, and formerly bred in southeast Russia and Northeast China, migrating in winter to southern China, Vietnam, Japan, and India. Baer's pochard is a monotypic species. The holotype was collected in middle Amur.
The New Zealand scaup, also known as the black teal or pāpango in Māori, is a diving duck species of the genus Aythya endemic to New Zealand. They weigh around 650 grams (23 oz) and measure around 40 centimetres (16 in), and have dark-coloured plumage. They are found throughout New Zealand in deep natural and man-made lakes and ponds.
The Maccoa duck is a stiff-tailed diving duck found across Eastern and Southern Africa.
The Patagonian crested duck, also known as the southern crested duck, or the grey duck in the Falkland Islands, is the nominate of two subspecies of the crested duck.
Susquehanna River National Wildlife Refuge is located on a small island 3.79 acres (15,300 m2) in size located at the mouth of the Susquehanna River in Harford County, Maryland. It is a satellite refuge managed by Blackwater National Wildlife Refuge. In the 1920s, the island was used as a fish hatchery to produce such species as shad.