Young lover losing independent bird (4)
I believe the answer is:
swan
'bird' is the definition.
(swan is a kind of bird)
'young lover losing independent' is the wordplay.
'young lover' becomes 'swain' (I've seen this before).
'losing' is a deletion indicator.
'independent' becomes 'i'.
'swain' with 'i' removed is 'SWAN'.
(Other definitions for swan that I've seen before include "The Ugly Duckling's outcome" , "Stately aquatic bird" , "Large, web-footed bird" , "Long-necked water bird" , "Flighty" .)