Bird from southern Europe (4)
I believe the answer is:
erne
'bird' is the definition.
(I know that grey sea eagle is a type of sea eagle)
'from southern europe' is the wordplay.
'from' says the answer is hidden in the clue.
'ERNE' is hidden within 'southern europe'.
(Other definitions for erne that I've seen before include "European sea eagle" , "Marine flyer" , "Irish river - sea eagle" , "Large bird" , "White-tailed eagle" .)