The bird fluttering out is able to (6)
I believe the answer is:
toucan
'the bird' is the definition.
(toucan is a kind of bird)
'fluttering out is able to' is the wordplay.
'fluttering' is an anagram indicator.
'is able to' becomes 'can' (I've seen this before).
'out' with letters rearranged gives 'tou'.
'tou'+'can'='TOUCAN'
(Other definitions for toucan that I've seen before include "Bird with large colourful beak" , "Tropical bird with large bill" , "Brightly-coloured tropical bird with large beak" , "Large-billed tropical bird" , "Bird with large, colourful bill" .)