American Green-Winged Teal Duck - Anas crecca
During the breeding season Green-winged Teal can be found in isolated river deltas, forest wetlands, and mixed prairie regions across northern North America. They nest in areas such as grasslands or sedge meadows that provide brush thickets of sedge or cattail for cover, and weedy or burned areas. They also favor beaver ponds in wooded areas, and nest along streams, potholes, lakes, and human-made wetlands. Migrating birds stop in shallow wetlands, coastal marshes, and flooded fields. Wintering birds inhabit shallow wetlands such as coastal marshes and estuaries as well as inland shallow lakes and ponds where there is standing or floating vegetation.
There is a population of the Green-winged Teal Ducks that can be found year round in the Aleutian Islands of Alaska, meaning they do not migrate. Most Green-winged teal ducks’, however, breeding grounds include much of Alaska and Canada. During the winter, most of the ducks inhabit the wetlands of much of the United States, as well as Central and South America.
Green-Winged Teal Ducks are the smallest North American dabbling ducks, with short necks and small bills. Males average at around 0.7 lbs. whereas the females average around 0.6 lbs. The males have a cinnamon colored head with an iridescent green band that runs from the eyes to the back of the head. The chest is pinkish-brown with black speckles, and the back, sides and flanks are gray, separated from the chest by a white bar. The wing coverts (set of feathers on the wings that cover other feathers) are brownish-gray with a green speculum. The bill is a dark slate and the feet are dark gray. Females are mottled brown with a dark brown line that extends from the bill through the eye. The bill is dark gray and the legs and feet are olive-gray to brownish-gray.
Green-winged teal ducks feed on seeds of sedges, smartweeds, pondweeds, grasses, aquatic insects, mollusks, crustaceans and tadpoles found while foraging in and adjacent to mudflats or while dabbling in shallow water. They feed either during the day or night. To feed on the very tiny invertebrates, the ducks use comb-like projections called lamellae, located around the inner edge of the bill, to filter them from the water.
First seen at the marsh that is located near the Bodie Lighthouse during the trip. There was both a male and female dabbling in the water next to the marsh tower.
Hanlon, Sm, et al. “Detection of Amphibian Chytrid Fungus on Waterfowl Integument in Natural Settings.” Diseases of Aquatic Organisms, vol. 126, no. 1, 2017, pp. 71–74., doi:10.3354/dao03160.
The chytrid fungus Batrachochytrium dendrobatidis (Bd) causes the amphibian disease chytridiomycosis, which has been thought to only infect amphibians. However, recent studies have found Bd in non-amphibian hosts as well. In this particular study the authors tried to detect Bd DNA in the feet of three duck species such as gadwalls, green-winged teals, and mallards via PCR. The authors concluded that these waterfowl species may act as vector hosts for Bd, which adds more animals to the list of becoming vulnerable to the fungus.
Väänänen, V., Nummi, P., Pöysä, H., Rask, M., & Nyberg, K. (2012). Fish-duck interactions in boreal lakes in Finland as reflected by abundance correlations. Hydrobiologia, 697(1), 85-93. doi:10.1007/s10750-012-1172-3
The authors of this study wanted to determine the ecological interactions between 3 species of ducks (mallard Anas platyrhynchos, green-winged teal A. crecca, and common goldeneye Bucephala clangula) and 3 species of fish (perch Perca fluviatilis, roach Rutilus rutilus, and pike Esox lucius) in boreal lakes of Southern Finland. The authors hypothesized that the ducks would be preyed upon by the pike, and that the ducks competed with the other 2 fish species. They found that there was a strong food competitive interaction between the perch, green-winged teal and goldeneye, for the other animals there was not much of an interaction.
Contributed by Tyler Theaker- 2018