Bird has drink with student (4)
I believe the answer is:
teal
'bird' is the definition.
(type of duck)
'drink with student' is the wordplay.
'drink' becomes 'tea' (tea is a drink).
'with' means one lot of letters go next to another.
'student' becomes 'L' (as in L-plates for learner drivers).
'tea'+'l'='TEAL'
'has' is the link.
(Other definitions for teal that I've seen before include "Bluish shade of green" , "Dark greenish-blue colour" , "Raise (subject matter)" , "Duck - dark greenish-blue" , "Type of duck" .)