Cozy retreats (5)
I believe the answer is:
nests
'cozy retreats' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nests that I've seen before include "Eyries" , "Structures for laying eggs" , "Settles comfortably into, as birds do" , "Places to rear the young?" , "Bird structures" .)