Songbird left where it could be trapped? (6)
I believe the answer is:
linnet
'songbird' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
(Other definitions for linnet that I've seen before include "Brown-gray kind of finch" , "Finch formerly popular as a pet" , "See three down" , "Winger" , "North London terminus" .)