A collector stuffing favourite bird (8)
I believe the answer is:
parakeet
'bird' is the definition.
(I know that parakeet is a type of parrot)
'a collector stuffing favourite' is the wordplay.
'collector' becomes 'rake' (I've seen this before).
'stuffing' means one lot of letters goes inside another.
'favourite' becomes 'pet' (synonyms).
'a'+'rake'='arake'
'arake' put inside 'pet' is 'PARAKEET'.
(Other definitions for parakeet that I've seen before include "Small long-tailed bird" , "Flier" , "Brightly-coloured African bird" , "Tropical bird" , "Bird popular as a pet" .)