Black bird of prey in hollow (4)
I believe the answer is:
bowl
'hollow' is the definition.
(I've seen this before)
'black bird of prey' is the wordplay.
'black' becomes 'b' (as in pencil classifications).
'bird of prey' becomes 'owl' (owl is a kind of bird of prey).
'b'+'owl'='BOWL'
'in' acts as a link.
(Other definitions for bowl that I've seen before include "Deliver - item of pottery" , "Greatly surprise" , "Round vessel - wooden ball" , "See 20" , "Throw the ball" .)