Tweeting site? (4)
I believe the answer is:
nest
'tweeting site?' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nest that I've seen before include "In which to lay eggs or give birth" , "Ingredient of Chinese soup" , "Bird's retreat" , "Roost" , "Sent to avian home" .)