Green-winged teal occupy a wide array of habitats throughout the year, much of which are determined by food availability. During the breeding season, they are found from boreal forest lakes to prairie potholes and tundra deltas. The greatest number of this species breeds in deciduous wooded ponds with dense surrounding cover. Sedge grass provides exceptional cover for nesting. During the migration, (Bull and Farrand, Jr., 1994; Guillemain, et al., 2006; Johnson, 1995)are found near and on all kinds of bodies of water. This includes marshes, ponds, lakes, mud flats, flooded crop fields, beaver ponds, rivers and bayous. In the Eurasia, they are more likely to inhabit salt-water coasts and shorelines and in the wintering areas, are typically found in brackish backwaters and salt flats rather than open salt water. Agricultural flooding and river deltas provide exceptional nutrients for the birds making them and ideal habitat as well.
This species is defined by its' distinctive green patch of secondary feathers found in both adult males and females. The smallest of the g. Anas in North America, is about 33-40 cm long. Their bills are short and narrow at about 3.5-4.0 cm. Relative to its body size, the bill is shorter than any other dabbling species except the American Widgeon Anas americana. Wing length is typically 17-19 cm while tail length ranges from 6.1-7.3 cm. Green-winged Teal are sexually dimorphic in their breeding plumage as well. Males have a rust colored head and green colored eye patch from above the eye, just short of the crown and nape, over the ear coverts extending back towards the base of the neck. They have a cream-colored breast with dark brown spots. Males have a grey back extending from the mantle to the rump. A triangular, yellow patch can be seen under the tail coverts. Flanks are dark grey while belly is a light grey. The American sub species has a vertical white stripe directly in front of the wing on the side of the body. The Eurasian subspecies has a white horizontal patch of feathers above the secondary flight feathers and a well-defined cream-colored outline around the green eye patch. Males appear similar to females while in eclipse plumage. Females are a mottled brown and tan over most their body. They have a white chin and belly with dark bills and fore-wings. They also have a greenish grey bill with faint spotting along the sides. The bills become plain grey as they mature. Both sexes have grey feet, dark brown irises, and whitish grey under-wings. Hatchling sexes are virtually indistinguishable based solely on their downy plumage. Their heads and bellies are yellow. From crown to rump, they are olive brown. They have yellow dorsal spots and pronounced brown eye stripes. Juvenile plumage is representative of female plumage in both sexes except female bellies are whiter than males. (Bull and Farrand, Jr., 1994; Cassidy, 1990; Johnson, 1995; Kear, 2005)
At one year of age, Green-winged teal are sexually mature and can breed. Social pairs begin to match up late September through November. This involves the male Green-winged teal bobbing his head up and down and even throwing it backwards then raising his chest off the water a few inches to impress females. Typically, 80% are paired before January; however, this may vary year to year based on the start of migration. Most mating pairs form by March in the grounds where they winter. Upon arrival, there can a lack of food at breeding grounds causing lower body masses. This requires the birds to carefully find a source of exogenous nutrients before nesting. During the mating season, Green-winged teal nest within 200 m of water. Nest building begins several days before egg laying. Hollow enclosures in sedge grass with down lining is typical. After breeding, they go through a flightless period in which they stay near their nests. Additionally, there is a small amount of interbreeding when a Eurasian teal finds its way to North America and visa versa. (Brochet, et al., 2010; Cassidy, 1990; Guillemain, et al., 2006; Johnson, 1995)
Female Green-winged teal do all the nest building while males follow behind. Egg laying begins in April-May where temperatures are warmest and early June in the coldest. Male Green-winged teal abandon the female after incubation begins. If the first clutch dies or the nest is destroyed, female Green-winged teal may lay a second clutch in July. One egg per day is laid producing 7-15 dull white, buff or even greenish colored eggs. In female Green-winged teal, 20-25% of stored energy is allocated towards egg production. Residual body stores allow rapid production of eggs and shorten the susceptible time on the nest. After the last egg is laid, the female Green-winged teal incubates the eggs for 20-23 days. About 80% of the day is spent on the nest with occasional 5-10 minute breaks to forage. The female Green-winged teal also provides all the care for the hatchlings including protection. (Cassidy, 1990; Johnson, 1995; Klaassen, 2002)
The typical lifespan of Green-winged teal varies greatly with location, food, weather, human impact, parasites etc. The oldest recorded (Johnson, 1995)was 20 years and 2 months old. About 40% of all eggs laid each year die before adulthood. Weather is also a large factor in mortality, due to their small size, high wind chills can be fatal. In the hardest years, mortality rates reported 50-72%. There is no data to suggest a higher mortality rate of males versus females
Diurnal Green-winged teal swim and fly most often for locomotion. However, they will hop from the water onto land to loaf on rocks, water edges, or low hanging branches. They are not typically seen resting in high branches. From rest, they are able to jump off the water or perch and take flight. This ability in addition to their high speed and agile movement on the wing makes them masters of flight Though they rarely dive for food, they will submerge themselves to avoid predators. Green-winged teal can often be seen preening their feathers, stretching their wings, dipping their head under water, shaking out their feathers and nibbling at each other. They are known to scratch their bills, even in flight. This action is thought to aid in the removal in leeches and other obstructions in their nasal passages. Sleeping typically occurs by standing on one leg, turning the head around and tucking the bill into the scapulars. Neither of these behaviors are more prevalent in either sex. During rest, they can be found in groups ranging from a few individuals to thousands. Green-winged teal also tend to spend a lot of time in large groups on the water. This grouping behavior is a way to show other Green-winged teal that there is food available and safety. (Cassidy, 1990; Johnson, 1995; Kear, 2005)
Most of the year Northern shoveler and Northern pintail. However, Green-winged teal have never been observed carrying out these actions on larger breeds. Contrary to these aggressive actions, males seem to show appeasement by swimming and nodding their heads up and down. (Guillemain, et al., 2006; Johnson, 1995)are found in large traveling groups. They are considered nomadic especially in first year juveniles. In groups, individuals communicate in several ways. Sounds threats, chasing and even fights occur by poking each other with their bills and hitting each other with their wings. These behaviors are more frequent in male Green-winged teal than females and are typically displays of dominance, especially on breeding and feeding grounds. Green-winged teal get attacked in these same ways by larger dabbling breeds most commonly the
Green-winged teal do not have a consistent home range. Apart from breeding grounds, they spend a lot time migrating and moving to where the food is. During the day, most of their time is spent at feeding locations until dusk when they return to a roost. In southern wintering grounds, Green-winged teal sometimes feed at night in agricultural fields to avoid some competition between larger dabbling species that use the same food sources. They must do a lot of foraging due to their small size and migratory patterns so whatever the most beneficial time to forage is, will likely be the time that they choose. (Brochet, et al., 2010; Paquette and Ankey, 1998)
Female Green-winged teal show contentment by 4-7 quacks in decrescendo. The sound is similar to that of a female Mallard but the tone is not as deep. Tireless quack vocalization is used in the breeding season, but subsides when nesting or with young. When in danger and taking off, 5-15 quacks at a rate of two per second is used to warn others and distract predators. Female Green-winged teal release a rattling call while inciting male Green-winged teal and produce loud squeals to repel male Green-winged teal during forced copulation and harassment. Male Green-winged teal make peeping and high-pitched abrupt whistles as well as low-pitched trills. In courtship, male Green-winged teal make a distinct “KRICK-eet” sound. A soft, slow, grunting whistle is made as well. Most vocalizations are not made while flying. Vocalizations in both sexes are more common in groups. Additionally, their wings make a whistling sound in flight. (Cassidy, 1990; Johnson, 1995)
Green-winged teal are known as opportunistic foragers feeding on things like insects and larvae, seeds of sedge grasses, aquatic vegetation both on and below the water’s surface. Green-winged teal are highly grainivorous in winter making up almost 95% of their diet in some populations. Rice, barley, and corn are among the most commonly consumed grains. They prefer shallow water; shorelines, mud flats, and flooded agricultural plots when available. Green-winged teal skim the surface using their bills and rush water through their bills while trapping food with the finely spaced comb like projections called lamella that line the edges of their bills. Ducklings’ diet is upwards of 90% insect larvae up until 14 days of age.
Feeding habits change throughout the year and their life. Weather, migration, and energy demands all play a part in these changes. The feeding habits of Green-winged teal depend heavily on pressures and competition from other dabbling duck species as well as predation. There can be a lack of food at the breeding grounds when they arrive increasing the need for foraging. They spend more than double the time foraging in rapid follicular growth than in pre-follicular growth. Additionally, female Green-winged teal spend more time foraging during incubation breaks than males and significantly more time than other g. Anas species. Many of these requirements are due to their small size and high metabolic rates. There is also a significant trade-off between feeding and vigilance. Feeding in groups allows more aggressive feeding but not significantly different levels of submerged feeding versus skimming. (Brochet, et al., 2010; Cassidy, 1990; Johnson, 1995; Klaassen, 2002; Paquette and Ankey, 1998; Pöysä, 1987)
Predation of Green-winged teal is not commonly observed, especially on the wing. However, it does occur. Bald eagles Haliaeetus leucocephalus, Spotted eagles Clanga clanga, White-tailed eagles Haliaeetus albicilla, Northern Harrier Circus cyaneus and Peregrine Falcon Falco peregrinus are notable predators known to attack Green-winged teal as they loaf on the water. Predation has also been observed by Harris' Hawks Parabuteo unicinctus but not as frequently as the other mentioned predatory species. Due to incubation of eggs on the ground, Red fox, Vulpes vulpes are known to take adults, 75% of those being female. There are accounts of Striped skunks, Mephitis mephitis predating on as well by raiding nests to steal eggs and occasionally kill chicks. Nest robbers such as American Crows, Corvus brachyrhynchos and Black-billed Magpies, Pica pica also play a role in predation of this species by eating Green-winged teal eggs. The earlier in the year those nests are built, the more susceptible they are to this form of predation due to lower amounts of surrounding foliage cover. Osprey, Pandion haliaetus can bother Green-winged teal as they are thought to misinterpret the Osprey as eagles and larger hawks that do pose a threat. In areas where predators have been observed, individuals tend to group together and spend more time scanning than actually eating, especially submerged feeding. This behavior lowers feeding efficiency. They have even been known to exploit the predatory warning calls of Black-headed Gulls, Larus ridibundus by increasing vigilance and scanning times once heard. (Johnson, 1995; Pöysä, 1987)
Green-winged teal fill a similar ecosystem role as many other waterfowl, especially puddle ducks. One of the biggest roles is the transportation of parasites from one location to another on their feet, in their stool, and on their feathers. A study conducted on Green-winged teal in southwest Texas showed that 72% of the captured individuals had some sort of parasite on them. In total, 17 species of endoparasites and 5 species of ectoparasites were found. The most common species found in Green-winged teal are g. Contracaecum larvae from stomach wall, Diorchis stefanskii from the small intestine, Hypoderaeum conoideum from the small intestine and Notocotylus attenuates from caecum. Juveniles also tend to have more parasites than adults but of those parasites there is less variation in species. Given the long migration, parasites can be transported a great distance. Similarly, these teal have a high rate of seed transportation through the passing of their stool. Most of the parasite that are transported are Green-winged teal are also known to travel in groups with other dabbling duck species such as the Mallard, Anas platyrhynchos, Northern Pintail, Anas acuta, and Blue-winged teal, Anas discors. This behavior leads to the Green-wings helping observe for predators, find food, and warn others essentially creating a mutualistic relationship. (Brochet, et al., 2010; Canaris, et al., 1981; Garvon, et al., 2011)
Green-winged teal have long been a game bird for waterfowl hunters around the globe. In the U.S. alone 1.7 million are shot each year making Green-winged teal second only to the Mallard, Anas platyrhynchos. Their numbers have increased enough over the last two decades that southern states such as Texas, Arkansas, and Missouri offer a teal exclusive hunting season before the normal season opens. This new season was adopted by the Midwest states of Michigan, Wisconsin and Iowa by 2017. These birds also offer many opportunities for birders. During the migration, many birders have the chance to watch this beautiful species. ("Migratory bird hunting activity and harvest during the 2013-14 and 2014-15 hunting seasons", 2015; "Waterfowl population status, 2015", 2015)
There is little negative economic impact of the Green-winged teal. As is with most avian species, Green-winged teal have the potential to spread diseases such as the avian flu through their saliva and feces. This disease (H5N1), though relatively uncommon, can pose a threat to humans as well. If contracted it can lead to flu-like symptoms or even death in human populations. Additionally, every year agriculture fields along the migration path suffer destruction by Green-winged teal but typically, it is not damaging to the point of significant economic loss.
Green-winged teal are of least concern globally. Their numbers are on the rise in most parts of the world, including the United States. As of 2015, the U.S. Fish and Wildlife Service estimate as North American breeding population of at least 4 million. This is double the long-term average for this species. Organizations worldwide work to keep the Green-winged teal populations healthy. State departments of natural resources and organizations such as Ducks unlimited play a crucial role in the conservation of the species. Bag limits based off population surveys, restrictions on lead shot, and banding programs have all played a part in this. Waterfowl hunters also do an insurmountable quantity of work to ensure the stability of the species. (BirdLife International, 2016; "Migratory bird hunting activity and harvest during the 2013-14 and 2014-15 hunting seasons", 2015; "Waterfowl population status, 2015", 2015)
Sam Golding (author), Northern Michigan University, Alec Lindsay (editor), Northern Michigan University.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
uses sound to communicate
living in landscapes dominated by human agriculture.
having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.
areas with salty water, usually in coastal marshes and estuaries.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
parental care is carried out by females
a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.
A substance that provides both nutrients and energy to a living thing.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
mainly lives in water that is not salty.
an animal that mainly eats seeds
An animal that eats mainly plants or parts of plants.
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
marshes are wetland areas often dominated by grasses and reeds.
makes seasonal movements between breeding and wintering grounds
Having one mate at a time.
having the capacity to move from one place to another.
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
the area in which the animal is naturally found, the region in which it is endemic.
an animal that mainly eats all kinds of things, including plants and animals
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
uses touch to communicate
Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
A terrestrial biome with low, shrubby or mat-like vegetation found at extremely high latitudes or elevations, near the limit of plant growth. Soils usually subject to permafrost. Plant diversity is typically low and the growing season is short.
uses sight to communicate
young are relatively well-developed when born
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Department of Interior. Waterfowl population status, 2015. Washington, D.C. USA: U.S. Department of the Interior. 2015. Accessed April 15, 2020 at https://www.fws.gov/migratorybirds/pdf/surveys-and-data/Population-status/Waterfowl/WaterfowlPopulationStatusReport15.pdf.
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Clausen, P., B. Nolet, A. Fox, M. Klaassen. 2002. Long-distance endozoochorous dispersal of submerged macrophyte seeds by migratory waterbirds in northern Europe – a critical review of possibilities and limitations. Acta Oecologica, 23: 191–203.
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McKinney, F., P. Stolen. 1982. Extra-pair-bond courtship and forced copulation among captive green-winged teal (Anas crecca carolinensis).. Animal Behaviour, 30: 461-474.
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