Fruit for a bird (4)
I believe the answer is:
kiwi
I believe this is a double definition.
'fruit' is the first definition.
(I know that kiwi is a berry)
'bird' is the second definition.
(kiwi is a kind of bird)
'for a' acts as a link.
(Other definitions for kiwi that I've seen before include "Someone from New Zealand?" , "Rutherford was one" , "Someone from Auckland?" , "Chinese gooseberry" , "New Zealand bird that does not fly" .)