Bovine creature following small island bird (9)
I believe the answer is:
bullfinch
'bird' is the definition.
(bullfinch is a kind of bird)
'bovine creature following small island' is the wordplay.
'bovine creature' becomes 'bull' (bovine means relating to cattle).
'following' becomes 'f' (used when citing page numbers etc).
'small island' becomes 'inch' (inch can mean a small island).
'bull'+'f'+'inch'='BULLFINCH'
(Other definitions for bullfinch that I've seen before include "Common garden bird" , "Bird with pink-breasted male" , "hedge" , "Bird that eats fruit buds" .)