Deceives the birds (5)
I believe the answer is:
gulls
I believe this is a double definition.
'deceives' is the first definition.
(gulling is a kind of deceiving)
'the birds' is the second definition.
(gull is a kind of bird)
(Other definitions for gulls that I've seen before include "Seabirds - dupes" , "mugs" , "Aquatic birds" .)