A party bird (3)
I believe the answer is:
hen
This clue is a double definition.
'a party' is the first definition.
(hen party is a kind of party)
'bird' is the second definition.
(hen is a kind of bird)
(Other definitions for hen that I've seen before include "Female bird" , "Composed of women" , "Clucking female" , "Source of eggs" , "Not cock" .)