Rescues southern birds (5)
I believe the answer is:
saves
'rescues' is the definition.
(saving is a kind of rescuing)
'southern birds' is the wordplay.
'southern' becomes 's' (abbreviation).
'birds' becomes 'aves' (I've seen this before).
's'+'aves'='SAVES'
(Other definitions for saves that I've seen before include "Rescues" , "Redeems or hoards" , "Preserves" .)