Perhaps hawk's attempt to catch rook (4)
I believe the answer is:
bird
'perhaps hawk's' is the definition.
(hawk is a type of bird)
'attempt to catch rook' is the wordplay.
'attempt' becomes 'bid' (bid is a kind of attempt).
'to catch' indicates putting letters inside.
'rook' becomes 'r' (abbreviation in chess).
'bid' enclosing 'r' is 'BIRD'.
(Other definitions for bird that I've seen before include "Egg-laying vertebrate" , "chat, perhaps?" , "Feathered animal" , "that flies" , "porridge" .)