The Green-winged Teal (Anas carolinensis) is a common and widespread duck which breeds in the northernmost areas of North America. It is the New World counterpart of the Eurasian Common Teal, Anas crecca , with which is was formerly considered conspecific.
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 drake Common Teal by a vertical, not horizontal white flank stripe, and the lack of thin buff lines on its head. In flight, the fast, twisting flocks resemble waders.
The females are light brown, with plumage much like a female Mallard. They can be distinguished from most ducks on size and shape, and the speculum. Separation from female Common Teal is problematic.
In non-breeding (eclipse) 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".