Distinguishing feature of bird artist captured (5)
I believe the answer is:
trait
'distinguishing feature' is the definition.
(I've seen this before)
'bird artist captured' is the wordplay.
'bird' becomes 'tit' (I've seen this before**).
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'captured' indicates putting letters inside.
'tit' enclosing 'ra' is 'TRAIT'.
'of' acts as a link.
(Other definitions for trait that I've seen before include "Decorative band" , "Feature of personality" , "Mannerism" , "Habit" , "Quirk" .)