Bird out, flying about, with tail of green (6)
I believe the answer is:
toucan
'bird' is the definition.
(toucan is a kind of bird)
'out flying about with tail of green' is the wordplay.
'flying' indicates anagramming the letters.
'about' becomes 'ca' (abbreviation for 'circa'**).
'with' is a charade indicator (letters next to each other).
'tail of' suggests the final letters.
The last letter of 'green' is 'n'.
'out' is an anagram of 'tou'.
'tou'+'ca'+'n'='TOUCAN'
(Other definitions for toucan that I've seen before include "Bird with large, colourful bill" , "exotic bird" , "Bird with large colourful beak" , "Bird with a large brightly-coloured bill" , "Tropical American bird with immense beak" .)