Bird's structure (4)
I believe the answer is:
nest
(Other definitions for nest that I've seen before include "See 21" , "home for 22d [VIPERS]" , "Make a home (birds)" , "Home of twigs, perhaps" , "In which to lay eggs or give birth" .)
I believe the answer is:
nest
(Other definitions for nest that I've seen before include "See 21" , "home for 22d [VIPERS]" , "Make a home (birds)" , "Home of twigs, perhaps" , "In which to lay eggs or give birth" .)