Fixed cut on a bird (6)
I believe the answer is:
toucan
'bird' is the definition.
(toucan is a kind of bird)
'fixed cut on a' is the wordplay.
'fixed' indicates anagramming the letters.
'cut'+'on'+'a'='cutona'
'cutona' anagrammed gives 'TOUCAN'.
(Other definitions for toucan that I've seen before include "Bird with large colourful beak" , "arboreal dweller" , "Large-billed tropical bird" , "Large-beaked bird" , "Sounds as if a pair is able for the tropical bird" .)