What does the slang word bird mean?

Orig., a chicken; the young of a fowl; a young eaglet; a nestling; and hence, a feathered flying animal (see 2)., A warm-blooded, feathered vertebrate provided with wings. See Aves., Specifically, among sportsmen, a game bird., Fig.: A girl; a maiden., To catch or shoot birds., Hence: To seek for game or plunder; to thieve.