Anas crecca

Geographic Range

In North America, Green-Winged Teal Anas crecca are found in northern Canada and Alaska down to the Dakotas, across the upper half of Michigan and over to Maine during breeding season. During migration, they inhabit the United States from the east coast near New York and Maryland west through Ohio and Kentucky over to South Dakota and Nebraska. Their winter range stretches from Virginia to California and all the way south to the Yucatan Peninsula and the Caribbean Islands. The year round range for A. crecca starts in the Rocky Mountains and stretches to Northern Colorado, Utah and Nevada then to the Canadian Border as well as on the Aleutian Islands. They are also found all throughout the European continent, from Iceland and Finland where they breed, to southern Spain, Italy, the Northern border of the Black Sea and Africa where they winter. They can be found in parts of Asia as well, breeding across northern Russia and Japan until migration when they move to south Asian countries with heaviest concentration being in India, Coastal China and the Nile region of Africa.

• Biogeographic Regions
• nearctic nearctic
  • native native
• palearctic palearctic
  • native native

Habitat

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, A. crecca 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.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial
• freshwater freshwater

• Terrestrial Biomes
• tundra tundra
• taiga taiga
• forest forest
• mountains mountains

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• coastal coastal
• brackish water brackish water

• Wetlands
• marsh marsh
• swamp swamp
• bog bog

• Other Habitat Features
• agricultural agricultural

Physical Description

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, A. crecca 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.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger
• sexes colored or patterned differently
• male more colorful

Reproduction

The monogamous mating system in A. crecca starts when a male picks out a suiting mate. Male Green-winged teal force copulation on females. Even if the female Green-winged teal is paired, males will attempt to breed. Female Green-winged teals try to avoid the males in this situation by fleeing and hiding but often are unsuccessful. Male Green-winged teal fight over females when this occurs, suggesting a strong sperm competition reproductive strategy. When a male Green-winged teal does catch a female, he pinches the back of her neck in his bill and pushes her down, sometimes completely under water. He then curls his body behind hers and inseminates her. This process usually takes less than 30 seconds.

• Mating System
• monogamous monogamous

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.

• Key Reproductive Features
• iteroparous iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

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.

• Parental Investment
• precocial precocial
• female parental care female parental care
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

The typical lifespan of Green-winged teal varies greatly with location, food, weather, human impact, parasites etc. The oldest recorded A. crecca 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

Behavior

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.

Most of the year A. crecca 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 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.

• Key Behaviors
• flies
• diurnal diurnal
• motile motile
• migratory migratory

Home Range

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.

Communication and Perception

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.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

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.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods
  • vermivore
• herbivore herbivore
  • granivore granivore
• omnivore omnivore

• Animal Foods
• insects
• terrestrial non-insect arthropods
• terrestrial worms
• aquatic or marine worms
• aquatic crustaceans

• Plant Foods
• leaves
• seeds, grains, and nuts
• fruit
• lichens
• algae

• Foraging Behavior
• filter-feeding filter-feeding

Predation

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 A. crecca 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.

• Anti-predator Adaptations
• aposematic aposematic

Ecosystem Roles

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.

• Ecosystem Impact
• disperses seeds

Economic Importance for Humans: Positive

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.

• Positive Impacts
• food food
• ecotourism ecotourism

Economic Importance for Humans: Negative

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.

• Negative Impacts
• injures humans
  • carries human disease
• crop pest

Conservation Status

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.

Additional Links

Encyclopedia of Life

Contributors

Sam Golding (author), Northern Michigan University, Alec Lindsay (editor), Northern Michigan University.

References

BirdLife International, 2016. "IUCN Red List of Threatened Species: Common Teal" (On-line). IUCN Red List of Threatened Species. Accessed April 14, 2020 at https://www.iucnredlist.org/species/22729717/86030704 .

Brochet, A., M. Gauthier-Clerc, M. Guillemain, et. al.. 2010. Field evidence of dispersal of branchiopods, ostracods and bryozoans by teal (Anas crecca) in the Camargue (southern France). Hydrobiologia , 637/255.

Bull, J., J. Farrand, Jr.. 1994. Field Guide to Birds (Eastern Region) . Alfred A. Knopf, Inc.: National Audubon Society.

Canaris, A., G. Ascension, C. Mena, J. Bristol. 1981. PARASITES OF WATERFOWL FROM SOUTHWEST TEXAS: III. THE GREEN-WINGED TEAL (Anas crecca). Journal of Wildlife Diseases , 17(1): 57-64.

Cassidy, J. 1990. Book of North American Birds . The Readers Digest Association Inc., New York: Readers Digest.

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.

Garvon, J., A. Fedynich, M. Peterson, D. Pence. 2011. Helminth Community Dynamics in Populations of Blue-Winged Teal ( Anas discors ) Using Two Distinct Migratory Corridors. Journal of Parasitology Research , 2011: 1-9.

Guillemain, M., C. Arzel, J. Mondain-Monval, V. Schricke, A. Johnson, G. Simon. 2006. Spring migration dates of teal Anas crecca ringed in the Camargue, southern France. Wildlife Biology , 12 (2): 163-169.

Johnson, K. 1995. "Birds of North America" (On-line). Cornell Lab of Ornithology. Accessed February 01, 2020 at https://birdsna.org/Species-Account/bna/species/gnwtea/introduction .

Kear, J. 2005. Ducks, Geese, and Swans: Species accounts (Cairina to Mergus) . Oxford University Press Inc., New York: Oxford.

Klaassen, M. 2002. Relationships Between Migration and Breeding Strategies in Arctic Breeding Birds. Avian Migration : 237–249.

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.

Paquette, G., D. Ankey. 1998. Diurnal time budgets of American Green-winged Teal Anas crecca breeding in British Columbia. Wildfowl , 49: 186-193.

Pöysä, H. 1987. Feeding-Vigilance Trade-Off in the Teal (Anas crecca): Effects of Feeding Method and Predation Risk. Bahviour , 103 (1/3): 108-122.

1998. Diurnal time budgets of American Green-winged Teal Anas crecca breeding in British Columbia. wildfowl , 46: 186-193.

U.S. Fish and Wildlife Service. Migratory bird hunting activity and harvest during the 2013-14 and 2014-15 hunting seasons. Laurel, MD, USA: 2015.

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 .