Smooth chap identifying a European songbird? (4,6)
I believe the answer is:
sand martin
'a european songbird?' is the definition.
'smooth chap' is the wordplay.
'smooth' becomes 'sand' (sanding is a kind of smoothing).
'chap' becomes 'martin' (**).
'sand'+'martin'='SAND-MARTIN'
'identifying' is the link.
(Other definitions for sand martin that I've seen before include "Migratory bird" , "Singer" , "Flyer" .)