Two different gulls or a woodpecker (9)
I believe the answer is:
sapsucker
'woodpecker' is the definition.
(I know that sapsucker is a type of woodpecker)
'two different gulls or a' is the wordplay.
I cannot really understand how this works, but
'gulls' could be 'saps' (both can mean gullible people) and 'saps' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for sapsucker that I've seen before include "woodpecker" , "Flyer" , "Dupes" , "bird" .)