Flightless bird of Australia (3)
I believe the answer is:
emu
'flightless bird of australia' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for emu that I've seen before include "Hull's character" , "one offering challenge to Hull?" , "Flightless bird of Australia, like ostrich" , "it can't get off the ground" , "Aussie runner" .)