Diving coastal bird (9)
I believe the answer is:
cormorant
'diving coastal bird' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for cormorant that I've seen before include "Large diving seabird" , "Proverbially gluttonous seabird" , "Large, voracious seabird" , "Large, long-necked seabird" , "Aquatic bird" .)