Old birds from two parties succeeded (5)
I believe the answer is:
dodos
'old birds' is the definition.
(dodo is an extinct bird)
'two parties succeeded' is the wordplay.
'two parties' means two substitutions for 'party'.
'party' becomes 'do' (do is a kind of party).
'party' becomes 'do' (do is a kind of party).
'succeeded' becomes 's' (genealogical abbreviation).
'do'+'do'+'s'='DODOS'
'from' is the link.
(Other definitions for dodos that I've seen before include "They never got up" , "they're no more" , "Extinct flightless birds" , "Extinct birds of Mauritius" .)