Hooting birds (4)
I believe the answer is:
owls
'hooting birds' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for owls that I've seen before include "Avian symbols of wisdom" , "Nocturnal birds" , "Slow (anag) -- birds of prey" , "Slow kind of birds" , "Nocturnal bird" .)