An animal and one flustered bird (6)
I believe the answer is:
pigeon
'bird' is the definition.
(type of bird)
'an animal and one flustered' is the wordplay.
'an animal' becomes 'pig' (pigs are animals).
'and' says to put letters next to each other.
'flustered' is an anagram indicator.
'one' is an anagram of 'eon'.
'pig'+'eon'='PIGEON'
(Other definitions for pigeon that I've seen before include "Bird of towns and woods" , "Dove-like bird" , "birdie" , "Bird with heavy body and short legs" , "Seed-eating bird" .)