Transport vehicle with central bit set aside for bird (4)
I believe the answer is:
lory
'bird' is the definition.
(lory is a kind of bird)
'transport vehicle with central bit set aside' is the wordplay.
'transport vehicle' becomes 'lorry' (I've seen this before).
'with central bit set aside' says to hollow out the word (remove centre letters).
'lorry' with its centre removed is 'LORY'.
'for' is the link.
(Other definitions for lory that I've seen before include "Australasian parrot" , "Small parrot" .)