Barn-dwelling birds (4)
I believe the answer is:
owls
'barn-dwelling 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" , "Slow sort of birds" , "Strigiform creatures" , "Wise old birds - quite slow" , "Nocturnal birds" .)