Castle corvid (4)
I believe the answer is:
rook
I believe this clue is a double definition.
'castle' is the first definition.
(I know that castle can be written as rook)
'corvid' is the second definition.
(Other definitions for rook that I've seen before include "Ringing in the ears" , "Crow-like bird" , "Chess piece also called castle" , "Gregarious black bird" , "man in marginalised position, initially" .)