Australia beak bipedal bird dromaius novaehollandiae Emu feathers flightless habitat leg native nature plumage walk caged captive compound eye gaol head jail menagerie neck sad wire zoo Australian big big bird cultural culture curious curly double-feathers fast fauna icon iconic large long-legged long-legged flightless bird male nomadic omnivore omnivorous ratite runner sharp-eyed soft-feathered symbol symbolic three-toed widespread wildlife