In an island race, there's only one winger (3)
I believe the answer is:
tit
'one winger' is the definition.
(tit is a kind of bird)
'in an island race there's only' is the wordplay.
'in' is an insertion indicator.
'an island race' becomes 'tt' (I've seen this in other clues).
'there's only' becomes 'i' (I can't explain this - if you can you should believe this answer much more).
'tt' enclosing 'i' is 'TIT'.
Can you help me to learn more?
(Other definitions for tit that I've seen before include "Small garden bird" , "Small songbird" , "useless horse, or not?" , "18's [BIRD]" , "Boob made backing" .)