Coastal raptor (4)
I believe the answer is:
erne
'coastal raptor' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for erne that I've seen before include "Great lake in Fermanagh with lots of islands" , "'Sea-eagle, river and lough (4)'" , "European sea eagle" , "flyer in the main" , "Sea-eagle in an Irish lake" .)