Green-winged teals are one of the worlds smallest dabbling ducks (Arzel et al., 2007). They are about crow-sized and weigh between 140 and 500 grams. They are about 31-39 cm long and have a wingspan of 52-59 cm.
There are 38 species of dabbling ducks and three separate subspecies of Anas crecca: A. c. crecca, A. c. carolinensis, A. c. nimia. Respectively the Common or Eurasian Teal, the Green-winged teal and the Aleutian teal (Sangster et al., 2001). The green-winged teal and the common teal males look similar but there are distinguishing factors such as where a white stripe is located on the body. It is difficult to discern between female common teals and female green-winged teals.
Photo by Albert Michaud of a male green-winged teal from Flickr
In common teal, there is a horizontal white stripe on the scapulars (Sibley et al., 2011) and in the green-winged teal, there is a vertical white stripe on the breast (Sangster et al., 2001). Green-winged teals have distinctive green speculum in their secondaries that is used to identify them. Eurasian teals are not very common in North America but do appear here occasionally (Baldassarre, 2014).Eurasian teals and Green-winged teals used to be classified into different species in the nineteenth century and today have been lumped into one species. There are, however, cases to split them back into two separate species using molecular data and species concepts (Peters et al., 2012, Sangster et al., 2001).
Distribution
Anas crecca carolinensis distribution winters in the midwest and the southern coast of California and Mexico represented by the blue. Is a resident in areas that are dark green which include Washington, Oregon, Montana, Idaho, and Colorado. The light green represents areas where the green-winged teal winters which is most of Canada and Alaska. The green-winged teal has a very broad distribution in North America from Canada to Mexico and from coast to coast. The breed up in Boreal forests in Canada and are well suited for the cold weather even though they’re small (Baldassarre, 2014).
Made by user The Engineer from Wikimedia Commons
Habitat
Green-winged teals nest in woodlands and shrub lands. For breeding purposes their habitat is in boreal forests, deciduous parkland, the taiga, rivers and deltas (Baldassarre, 2014).
Food Habits
Green winged teals have 7 foraging strategies when they are in the water: Fly catching, grazing, diving, bill underwater, head underwater, neck underwater, diving, and upending (Arzel, 2007). They mostly try to graze from the top but do go deeper in the water when food gets scarce (Pöysä, 1989) which usually happens near the end of the day (Pöysä, 1987). Green-winged teals try to forage for food in groups to lower the risk of predation since their model of feeding is based on vigilance (Pöysä, 1987).
Green-winged teals graze the water for invertebrates like brine shrimp, brine shrimp cysts, freshwater and brackish invertebrates, usually corixids, and wetland plant seeds (Roberts and Conover, 2014, Vest and Conover, 2011).
Sounds
Grunt whistle and chittering noises have been described as sounds a Green-winged teal make (McKinney,1965).
Male whistle
Call
Both recordings by Bruce Lagerquist in Washington from xeno-canto.
Behavior
Green-winged teals have similar courtship movements as Mallards do but faster. Males that are trying to court a female will aggregate around her and undertake social courtship (McKinney,1965). They do a series of displays to attract a female. Both male and female green-winged teals as males look for iridescence in female wing flashes (Legagneux et al.,2010).
Green-winged teals also exhibit foraging habits in which they forage in large groups and uses the need for food to outweigh the predation risk that comes with foraging (Pöysä, 1991). They are also more likely to stop somewhere to forage if they find other teals at that location. During the foraging as the day goes on the green-winged teal starts to forage deeper in the water (Pöysä, 1989). Green-winged teals spend almost half of a 24 hr cycle in winter foraging and up to 87.5% of the 24 hr period in spring and summer foraging. The percentage goes up in spring and summer because of the energy that is taxed during breeding season (Arzel, 2007). In the spring and summer green-winged teals exhibit a behavior called income breeding, which entails that green winged teals do not stock up on energy needed for breeding season before but actively gains food when trying to breed. (Stephens et al., 2009, Arzel 2007).
The reproductive success of a paired green-winged teals is dependent on how early they arrive to a nesting site (Arzel, 2007). They usually take about 49 days to build a nest after they arrived at the breeding site and they are considered early nesters in general when compared to other dabbling ducks (Raquel et al., 2016).
Population Trends and Conservation Issues
The family Anatidae is one of the most hunted game in the world. Therefore there is conservation efforts to make sure that ducks have habitat and are able to be hunted. Surveys count American green-winged teals in 2010 to be about 3.5 million with an intense distribution. Which includes most of Canada, Alaska, the eastern Dakotas, Washington, Oregon, California, Montana, and Nevada. In a survey between 1999 and 2010 the average population of green-winged teals was estimated to by 3,440 (Baldassarre, 2014).
Literature Cited
Koerner, T. (2015, December 03). Green-Winged Teal Drakes on Seedskadee NWR. Retrieved February 28, 2019, from https://www.flickr.com/photos/usfwsmtnprairie/23476831536
Pöysä, H. (1989). Foraging Patch Dynamics in the Teal (Anas crecca): Effects of Sociality and Search Method Switching. Behaviour,110(1/4), 306-318. Retrieved from http://www.jstor.org/stable/4534799
Pöysä, H. (1987). Feeding-Vigilance Trade-Off in the Teal (Anas crecca): Effects of Feeding Method and Predation Risk. Behaviour,103(1/3), 108-122. Retrieved from http://www.jstor.org/stable/4534637
McKinney, F. (1965). The Displays of the American Green-Winged Teal. The Wilson Bulletin,77(2), 112-121. Retrieved from http://www.jstor.org/stable/4159365
Rave, D., & Baldassarre, G. (1989). Activity Budget of Green-Winged Teal Wintering in Coastal Wetlands of Louisiana. The Journal of Wildlife Management,53(3), 753-759. doi:10.2307/3809208
Tore Buchanan, Rodney W. Brook, Matthew P. Purvis, & J. Chris Davies. (2015). Quantifying Moonlight and Wind Effects on Flighted Waterfowl Capture Success During Night-Lighting. Wildlife Society Bulletin (2011-),39(1), 169-173. Retrieved from http://www.jstor.org/stable/wildsocibull2011.39.1.169
Vest, J., & Conover, M. (2011). Food Habits of Wintering Waterfowl on the Great Salt Lake, Utah. Waterbirds: The International Journal of Waterbird Biology,34(1), 40-50. Retrieved from http://www.jstor.org/stable/23018366
Stephens, P. A., Boyd, I. L., McNamara, J. M., & Houston, A. I. (2009, August). Capital breeding and income breeding: Their meaning, measurement, and worth. Retrieved March 13, 2019, from https://www.ncbi.nlm.nih.gov/pubmed/19739368
Roberts, A. J., & Conover, M. R. (2014). Diet and body mass of ducks in the presence of commercial harvest of brine shrimp cysts in the Great Salt Lake, Utah. Journal of Wildlife Management, 78(7), 1197–1205. https://doi.org/10.1002/jwmg.759
PETERS, J. L., McCRACKEN, K. G., PRUETT, C. L., ROHWER, S., DROVETSKI, S. V., ZHURAVLEV, Y. N., … WINKER, K. (2012). A parapatric propensity for breeding precludes the completion of speciation in common teal ( Anas crecca, sensu lato). Molecular Ecology, 21(18), 4563–4577. https://doi.org/10.1111/j.1365-294X.2012.05711.x
Raquel, A. J., Devries, J. H., Howerter, D. W., Alisauskas, R. T., Leach, S. W., & Clark, R. G. (2016). Timing of nesting of upland-nesting ducks in the Canadian prairies and its relation to spring wetland conditions. Canadian Journal of Zoology, 94(8), 575–581. https://doi-org.evergreen.idm.oclc.org/10.1139/cjz-2016-0021
Baldassarre, G. 2014. Ducks, geese, and swans of North America. Johns Hopkins University Press, Baltimore, Md.
About the Author
Lou Leohner is a Junior at the Evergreen State College studying Botany and Integrated Natural systems. She is interested in how organisms relate to one another and how those relationships affect other organisms and ecosystems as a whole.
Leave a Reply