Bad weather hampering a bird (8)
I believe the answer is:
wheatear
'bird' is the definition.
(wheatear is a kind of bird)
'bad weather hampering a' is the wordplay.
'bad' indicates anagramming the letters.
'hampering' means one lot of letters goes inside another (hamper can mean to obstruct or restrain).
'weather' with letters rearranged gives 'wheater'.
'wheater' enclosing 'a' is 'WHEATEAR'.
(Other definitions for wheatear that I've seen before include "singer" , "Songbird" , "bird" , "Migrant's passion" .)