look up any word, like ratchet:
a member of any number of species of grebes (a small, duck-like wild bird), most of which are only distinguishable at a distance from a duck due to their comparatively recessive hindquarters.
"I thought that was a duck sitting on the pond, but it didn't have much of an ass on it; it musta been an assless curlybird."
by Brodsgaard November 23, 2003