The Green-winged Teal (Anas carolinensis) is a common and widespread duck found in the northernmost areas of North America. It is the New World counterpart of the Eurasian Common Teal (Anas crecca) with which it is sometimes considered conspecific.
This dabbling duck is strongly migratory and winters to the far south of its breeding range. It is highly social outside of the breeding season and will form large flocks. In flight, these fast, twisting flocks resemble waders.
This is the smallest North American dabbling duck. The breeding male has grey flanks and back, with a yellow rear end and a white-edged green speculum, obvious in flight or at rest. It has a chestnut head with a green eye patch. It is distinguished from the Common Teal by a vertical (as opposed to a horizontal) white flank stripe, as well as by the lack of thin buff lines on its head.
The females are light brown with plumage much like a female Mallard. They can be distinguished from most ducks by their size and shape, as well as the speculum. Separation from female Common Teal is problematic.
In non-breeding plumage, the drake looks more like the female.
It is a common duck of sheltered wetlands, such as taiga bogs, and usually feeds by dabbling for plant food or grazing. It nests on the ground, near water and under cover.
This is a noisy species. The male has a clear whistle, whereas the female has a feeble “quack”.