Bird beginning to nod after wild party (5)
I believe the answer is:
raven
'bird' is the definition.
(raven is a kind of bird)
'beginning to nod after wild party' is the wordplay.
'beginning to' says to take the initial letters.
'after' says to put letters next to each other.
'wild party' becomes 'rave' (I've seen this before).
The initial letter of 'nod' is 'n'.
'n' after 'rave' is 'RAVEN'.
(Other definitions for raven that I've seen before include "Bird in 1's poem" , "Bird with hoarse, croaking cry" , "Black crow" , "Crow-like bird" , "Large bird of the crow family" .)