Blue-winged Teal (Anas discors)

Jan 27, 2019 Features / Columnists, Interesting Creatures in Guyana

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The blue-winged teal (Anas discors) is a small dabbling duck from North America. It has reportedly been found in South American territories too. The scientific name is derived from Latin Anas “duck”, and discors, “variance”, which may refer to the striking face pattern of the male.
The blue-winged teal is 40 cm (16 in) long, with a wingspan of 58 cm (23 in), and a weight of 370 g (13 oz). The adult male has a greyish blue head with a white facial crescent, a light brown body with a white patch near the rear and a black tail. The adult female is mottled brown, and has a whitish area at base of bill. Both sexes have sky-blue wing coverts, a green speculum, and yellow legs. They have two molts per year and a third molt in their first year. The call of the male is a short whistle; the female’s call is a soft quack.
The placement of the blue-winged teal or Anas discors in the genus Anas is by no means certain; a member of the “blue-winged” group also including the shovelers, it may be better placed with them in a separate genus Spatula. It is not a teal in the strict sense, and also does not seem closely related to the garganey as was for some time believed. Indeed, its colour pattern is strikingly reminiscent of the Australasian shoveler.
DNA analysis of this species has revealed it is very close genetically to the cinnamon teal, another American teal with blue wings.
It is often seen wintering as far south as Brazil and central Chile.
Blue-winged teal inhabit shoreline more often than open water and prefer calm water or sluggish currents to fast water. They inhabit inland marshes, lakes, ponds, pools, and shallow streams with dense emergent vegetation. In coastal areas, breeding occurs in salt-marsh meadows with adjoining ponds or creeks. Blue-winged teal use rocks protruding above water, muskrat houses, trunks or limbs of fallen trees, bare stretches of shoreline, or mud flats for resting sites.
Blue-winged teal winter on shallow inland freshwater marshes and brackish and saltwater marshes. They build their nests on dry ground in grassy sites such as bluegrass meadows, hayfields, and sedge meadows. They will also nest in areas with very short, sparse vegetation. Blue-winged teal generally nest within several hundred yards of open water; however, nests have been found as far as 1.61 km (1 mi) away from water. Where the habitat is good, they nest communally.
Blue-winged teal often use heavy growth of bulrushes and cattails as escape cover. Grasses, sedges, and hayfields provide nesting cover for these ducks. These birds feed by dabbling in shallow water at the edge of marshes or open water. They mainly eat plants; their diet may include molluscs and aquatic insects.
Blue-winged teal are generally the first ducks south in the fall and the last ones north in the spring. Adult drakes depart the breeding grounds well before adult hens and immatures. Most blue-winged teal flocks seen after mid-September are composed largely of adult hens and immatures.
The onset of courtship among immature blue-winged teal often starts in late January or early February. In areas south of the breeding grounds, blue-winged teal are more active in courtship during the spring migration than are most other ducks.
Blue-winged teal are among the last dabbling ducks to nest, generally nesting between April 15 and May 15. Few nests are started after mid-July. Chronology of nesting can vary from year to year as a result of weather conditions.
They generally lay 10 to 12 eggs. Delayed nesting and renesting efforts have substantially smaller clutches, averaging five to six eggs. Clutch size can also vary with the age of the hen. Yearlings tend to lay smaller clutches. Incubation takes 21 to 27 days.
Blue-winged teal are sexually mature after their first winter. During incubation, the drake leaves its mate and moves to suitable molting cover where it becomes flightless for a period of three to four weeks.
Blue-winged teal ducklings can walk to water within 12 hours after hatching but do not fledge until six to seven weeks.
Blue-winged teal are surface feeders and prefer to feed on mud flats, in fields, or in shallow water where there is floating and shallowly submerged vegetation plus abundant small aquatic animal life. They mostly eat vegetative matter consisting of seeds or stems and leaves of sedge, grass, pondweed, smartweed, duckweed, Widgeongrass, and muskgrass.
The seeds of plants that grow on mud flats, such as nutgrass, millet and Rice Cut-grass, are avidly consumed by this duck. One-fourth of the food consumed by blue-winged teal is animal matter such as mollusks, crustaceans, and insects.
Common predators of blue-winged teal include humans, snakes, snapping turtles, dogs, muskellunge, American crows, magpies, ground squirrels, coyotes, red foxes, grey foxes, raccoons, long-tailed weasels, American minks, striped skunks, spotted skunks, and American badgers. (Source: Wikipedia)

 

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