Large Australian bird (3)
I believe the answer is:
emu
'large australian bird' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for emu that I've seen before include "one offering challenge to Hull?" , "Flightless bird of Australia, like ostrich" , "it can't get off the ground" , "Fast runner in Oz" , "Flightless Aus. bird" .)