The breeding male is unmistakeable. The females are light brown with a whiter throat, and their pointed tail is shorter, but they are easily identified by their shape, long neck, and long all grey bill.
In non-breeding (eclipse) plumage, the drake looks more like the female.
It is a bird of open wetlands, such as wet grassland or tundra, and feeds by dabbling for plant food mainly in the evening or at night. It nests on the ground.
The male has a Teal-like whistle, whereas the feamle has a mallard-like quack.
There are two isolated island races, A. a. eatoni, (Eaton's Pintail) of Kerguelen Island, and A. a. drygalskyi (Crozet Pintail) of Crozet Island in which the males do not develop the full breeding plumage.