Bad bird heard to be wrong (7)
I believe the answer is:
illegal
'be wrong' is the definition.
(I've seen this before)
'bad bird' is the wordplay.
'bad' becomes 'ill' (associated in meaning).
'bird' becomes 'egal' (I can't explain this - if you can you should believe this answer much more).
'ill'+'egal'='ILLEGAL'
'heard to' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for illegal that I've seen before include "Unlawful" , "Not in conformity with law" , "Black-market" , "Criminal, illicit" , "Against the rules" .)