Anas Crecca is smallest dabbling duck, the Green-winged Teal is smaller and more compact than other teals and has a round head and narrow bill. All sexes and ages have dark gray wings with green-black speculums and a brown bar above each speculum. Females and juveniles are mottled brown overall with gray legs. Males in breeding plumage have gray bodies with orange-buff, dark-spotted breasts and yellow patches on their flanks. Their rumps are black and buff, and their rufous heads have an iridescent green band swooping back in a curve on each side. They also have a vertical white shoulder-bar on each side, which can be a helpful field mark when trying to distinguish the Green-winged Teal from the Eurasian race.
The Green-winged Teal lives in shallow wetlands, preferring fresh water for breeding, but is resident on both fresh and salt water at other times of the year. Nesting habitat usually has trees and shrubs. During winter and migration, wetlands with a lot of emergent and floating vegetation are commonly used. Tidal mudflats are used by this species more often than by any other duck.
Green-winged Teals usually gather in smallish flocks, but large flocks of thousands are also seen. Active and agile, they forage in emergent vegetation along shorelines and in wet, shallow, muddy areas, mainly by dabbling their bills at the water’s surface. Because of their small size and rapid wing-beats, these birds in flight appear to move very fast.
Green-winged Teals usually arrive at the breeding grounds with pair bonds formed. Nests are usually located in grasses and weeds in meadows, open woodlands, or brush, and are usually within two hundred feet of water. The female builds the nest on the ground. It is well hidden by low vegetation that often is dense enough to form a full canopy over the nest. The nest itself is usually a shallow depression, filled with grasses, twigs, and leaves, lined with down. Incubation is by the female alone, and lasts for 20 to 24 days, during which time the pair bond dissolves, and the male leaves the nesting area. Within a few hours of hatching, the 8 to 9 ducklings leave the nest with the female to look for their own food. They may all return to the nest at night for a few days. The young fledge at about 35 days.