Flightless birds in muddle not using wings (4)
I believe the answer is:
emus
'flightless birds' is the definition.
(emu is a kind of flightless bird)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for emus that I've seen before include "Fast, but not high-fliers" , "Large flightless birds of Australia" , "Muse about flightless Australian birds" , "laboratory units" , "Aussie birds" .)