The little Green-winged Teal is the smallest dabbling duck in North America. The natty male has a cinnamon-colored head with a gleaming green crescent that extends from the eye to the back of the head. In flight, both sexes flash deep-green wing patches (specula). Look for them on shallow ponds and in flooded fields, and listen for the male’s decidedly non-ducklike whistle. These common ducks breed along northern rivers; wintering flocks can number as many as 50,000.More ID Info
A good time to look for Green-winged Teal across most of the continent is during spring and fall migration, when the birds land in shallow wetlands, sometimes foraging in little more than puddles in flooded agricultural fields. They occur with other species of dabbling ducks, but they’ll stand out if you pay attention to their size and shape. Even the fairly uniform brown females are distinctive by silhouette: small and compact, sitting high in the water, with a fairly small bill. A small brown duck near a group of larger dabblers is probably not a young Mallard—and it could be a female Green-winged Teal. Look for the buffy yellow stripe along the tail for extra confirmation.