What is "stiff-tailed duck"

n. a duck of the Oxyurinae subfamily of ducks.

The Stiff-tailed ducks, Oxyura, are part of the Oxyurinae subfamily of ducks. The genus name is derived from Ancient Greek oxus, "sharp", and oura, "tail".

All have, as their name implies, long, stiff tail feathers, which are erected when the bird is at rest. All have relatively large, swollen bills. These are freshwater diving ducks. Their legs are set far back, making them awkward on land, so they rarely leave the water.

Their unusual displays involve drumming noises from inflatable throat sacs, head throwing, and erecting short crests. Plumage sequences are complicated, and aging difficult. Plumage is vital for survival because of this animals tendency to spend time in the water.

The six extant members of this genus in summation are distributed widely throughout North America, South America, Australia, Asia, and much of Africa.