Drink left for bird (4)
I believe the answer is:
teal
'bird' is the definition.
(teal is a kind of bird)
'drink left' is the wordplay.
'drink' becomes 'tea' (tea is a kind of drink**).
'left' becomes 'l' (common abbreviation).
'tea'+'l'='TEAL'
'for' is the link.
(Other definitions for teal that I've seen before include "Type of duck" , "bird" , "Dark green-blue; duck" , "Species of duck" , "Variety of duck" .)