Anas discors
blue-winged teal

During the summer months, blue-winged teal can be found throughout North America, from southeastern Alaska (western limit) to the Atlantic coast (eastern limit). They are also found in the continental U.S. in the Great Plains as far south as the Gulf Coast of Texas and Louisiana. In the winter months they migrate southwards to the Carolinas, southern California, and New Mexico and into tropical South America. Although Anas discors is commonly found in Neartic regions, it is also found in Australia. These ducks breed in southern Alaska and western Canada and south to northwestern California, New Mexico, and New York. (Lemaster, 1985)

Freshwater habitats for Anas discors include shallow ponds and seasonal and permanent wetlands. They often use both temporary and permanent ponds. During breeding season, blue-winged teal remain near the water's edge in ponds and wetlands, preferring to breed in areas of calm, sluggish water. (Bennett, 1938)

Anas discors are called blue-winged teal because both sexes have blue spots on their forewings. They also have large white patches on the front of the wing, best visible when in flight. Males are smaller than females. Males have a large vertical white crescent on their face, between the eye and the bill, and a white patch on their rear flank. Females lack the crescent and white patch, with dull gray-brown coloration.

Wingspans range from 56 to 62 cm, and total lengths are typically 36 to 41 cm. Adults weigh 280 to 499 g. (Guillemain et al., 2007)

Ducklings are susceptible to parasites and diseases, and often do not reach maturity. Botulism (Clostridium botulinum) and avian cholera (Pasteurella multocida), both bacterial diseases, impact blue-winged teal populations heavily through ingestion of the bacteria. Migration is another source of mortality, particularly in young teal. Blue-winged teal that do survive to adulthood have been known to live up to 17 years. (Rohwer, Johnson, and Loos, 2002)

Blue-winged teal are highly gregarious, tending to move in or form a group with others of the same species. The only time they are not social is during breeding season. Blue-winged teal migrate between wintering and breeding ranges each year. They are generally subordinate to larger-bodied dabbling and diving ducks. They are active during the day. Blue-winged teal can walk well on land and in shallow water. They are not known for climbing, but they often rest and preen on logs and rocks that are slightly above water. They can gain flight directly from land or water. The only time a blue-wing teal will dive in the water is if threatened by a predator or when trying to escape copulation attempts. Blue-winged teal use preening, head-scratching, and stretching of the body to self-clean. (Rohwer, Johnson, and Loos, 2002)

Home Range

Blue-winged teal establish small territories around nests during the breeding season. During the remainder of the year they do not defend territories or remain within a set home range. (Rohwer, Johnson, and Loos, 2002)

Males that are unpaired usually make a loud, high-pitched whistle "peew" or a low-pitched nasal "paay." A male's decrescendo begins with a single call that is followed by a short series of low-pitched "pews." These types of calls are broadcast during fall and early winter, but rarely after pair formation.

During the mating season, females give a short series of loud, evenly- spaced, single quacks, which vary in volume and duration. When a female that has already found a mate is being pursued by another male, she makes a quack sound followed by a "gaek" note to warm them off. Females also quack to communicate with their young. (Rohwer, Johnson, and Loos, 2002)

Blue-winged teal consume a variety of aquatic invertebrates, including insects, crustaceans, snails, and small clams, and aquatic vegetation, including seeds. When females are breeding they require a diet higher in protein, so they eat more invertebrates and seeds. (Rohwer, 1986)

Long-tailed weasels Mustela frenata often consume blue-wing teal eggs. Females are susceptible to predation by raptors when incubating and when walking near nests between incubation bouts. In prairies, these ducks are captured by red foxes Vulpes vulpes. Females and ducklings are cryptically colored to avoid detection by prey.

Other predators include: peregrine falcons (Falco peregrinus), minks (Neovison vison), raccons (Procyon lotor), bald eagles (Haliaeetus leucocephalus), great horned owls (Bubo virginianus), red-tailed hawks (Buteo jamaicensis), coyotes (Canis latrans), striped skunks (Mephitis mephitis), American badgers (Taxidea taxus), American crows (Corvus brachyrhynchos), black-billed magpies (Pica hudsonia), and Franklin's ground squirrels (Spermophilus franklinii). (Rohwer, Johnson, and Loos, 2002)

Most blue-winged teal live mutualistically with other dabbling ducks. There are many parasites that infect this species, including Pasteurella multocida (avian cholera), and protozoans, such as Cyanthocotyle bushiensis and Spahaeridotreme globulus. (Rohwer, Johnson, and Loos, 2002)

One concern about blue-winged teals is the spread of avian influenza, which can decimate bird populations and be transmitted to humans. (Rohwer, Johnson, and Loos, 2002)

Blue-winged teal are game birds. (Rohwer, Johnson, and Loos, 2002)

Blue-winged teal, although not rare, are protected under the Migratory Bird Act. Bag limits are set to maintain healthy populations. Also, the U.S. and Canada have banned pesticides and other contaminants that had been killing blue-winged teals. For instance, mercury levels and also organochlorine residue found in lakes and ponds are controlled/limited by these governments. Dieldrin is a type of insecticide that can concentrate in migratory birds--it has since been banned.

Humans often negatively affect Anas discors. Human littering can cause suffocation in this bird--from consuming or getting stuck in plastic trash and fishing lines. Also, blue-winged teal can collide with power lines, fences, and barbed wire in flight, or with vehicles. However, the most important negative influence is habitat degradation and loss due to human activities, especially wetland draining and conversion to agriculture. (Rohwer, Johnson, and Loos, 2002)