Bird for felon with diamonds and gold (6)
I believe the answer is:
condor
'bird' is the definition.
(condor is a kind of bird)
'felon with diamonds and gold' is the wordplay.
'felon' becomes 'con' (abbreviation for 'convict').
'with' says to put letters next to each other.
'diamonds' becomes 'd' (abbreviation in bridge say).
'and' means one lot of letters go next to another.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'con'+'d'+'or'='CONDOR'
'for' acts as a link.
(Other definitions for condor that I've seen before include "Great bird of the Andes" , "Large bird of the Andes (national symbol of Peru)" , "Large vulture of S America" , "Large bird of prey" , "Andean bird" .)