Bird causes fight and argument (7)
I believe the answer is:
sparrow
'bird' is the definition.
(sparrow is a kind of bird)
'fight and argument' is the wordplay.
'fight' becomes 'spar' (sparring is a kind of fighting).
'and' is a charade indicator (letters next to each other).
'argument' becomes 'row' (to row is to argue).
'spar'+'row'='SPARROW'
'causes' acts as a link.
(Other definitions for sparrow that I've seen before include "Robin's slayer" , "Small songbird" , "one on the wing" , "A chirrupy city bird" , "A small chirpy city bird 97)" .)