Hear, moving right to front, a flightless bird (4)
I believe the answer is:
rhea
'flightless bird' is the definition.
(I know that rhea is a type of flightless bird)
'hear moving right to front a' is the wordplay.
'hear' can be anagrammed to 'RHEA'.
However, I am unsure how this is indicated.
(Other definitions for rhea that I've seen before include "Flightless bird from South America" , "S. Amer. flightless bird" , "Fertility goddess in ancient Greek mythology" , "Flightless bird -- satellite of Saturn" , "China grass" .)