A wizard bird! (6)
I believe the answer is:
merlin
This clue is a double definition.
'a wizard' is the first definition.
(I've seen this before)
'bird' is the second definition.
(merlin is a kind of bird)
(Other definitions for merlin that I've seen before include "small aggressive bird of prey" , "Legendary magician" , "Arthur's sorcerer" , "Magician of the Round Table" , "Magician of legend - falcon" .)