Extinct flightless bird of New Zealand (3)
I believe the answer is:
moa
'extinct flightless bird of new zealand' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for moa that I've seen before include "Extinct flightless bird of New Zealand" , "Bird no longer" , "Bird's gone for ever" , "was hunted by Maori" , "Extinct flightless NZ_bird" .)