stifftail 
(also stiff-tailed duck)
noun
A diving duck with a stiff tail of pointed feathers, often held up at an angle.
- Family Anatidae: four genera, in particular Oxyura, and several species, e.g. the ruddy duck.
- Some of his books are technical surveys of groups such as owls, hummingbirds, and stifftail ducks.
- Modern authors accept that we are dealing with two species of stifftail in Europe.