Seagull kin (4)
I believe the answer is:
tern
'seagull kin' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tern that I've seen before include "Sea bird, a small gull" , "Small gull with forked tail" , "Long-winged aquatic bird" , "Rent out the bird" , "Fork-tailed seabird" .)