Bird, poor flier — deaf (9)
I believe the answer is:
fieldfare
'bird' is the definition.
(fieldfare is a kind of bird)
'poor flier deaf' is the wordplay.
'poor' indicates an anagram.
'flier'+'deaf'='flierdeaf'
'flierdeaf' with letters rearranged gives 'FIELDFARE'.
(Other definitions for fieldfare that I've seen before include "Speckled bird" , "Deaf flier (anag) - migratory thrush" , "Flighty singer" , "Migratory thrush -- FA ref lied (anag)" .)