Watch it! He's angling for trouble (12)

I believe the answer is:

nightingales

'watch' is the definition.
(collective noun for a group of nightingales)

'it he's angling for trouble' is the wordplay.
'for trouble' indicates anagramming the letters (letters get in messed up or in trouble).
'it'+'hes'+'angling'='ithesangling'
'ithesangling' anagrammed gives 'NIGHTINGALES'.

(Another definition for nightingales that I've seen is " Songbirds".)

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app