Bird is in hide (6)
I believe the answer is:
siskin
'bird' is the definition.
(siskin is a kind of bird)
'is in hide' is the wordplay.
'in' is an insertion indicator.
'hide' becomes 'skin' (a hide is an animal skin).
'is' placed within 'skin' is 'SISKIN'.
(Other definitions for siskin that I've seen before include "Little bird" , "Breed of finch" , "Greenish songbird of finch family" , "Winger" , "Small bird - kiss in (anag)" .)