Fish hawks (7)
I believe the answer is:
'fish hawks' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ospreys that I've seen before include "Sea hawks and members of a British rugby team" , "Fishing birds" , "Fish-eating birds of prey" , "Preys so close to fishing eagles" , "Fish-eating hawks" .)