Chess piece, or a bird (4)
I believe the answer is:
rook
I believe this clue is a double definition.
'chess piece' is the first definition.
(I know that rook is a type of chess piece)
'a bird' is the second definition.
(rook is a kind of bird)
(Other definitions for rook that I've seen before include "Steal - castle" , "Rip off - bird" , "Gregarious black bird" , "Swindle; castle" , "flier" .)