Dromornithidae

Dromornithidae, known as mihirungs (after Tjapwuring Mihirung paringmal, "giant bird") and informally as thunder birds or demon ducks, is an extinct family of large, flightless birds native to Australia from at least the late Oligocene (and perhaps as early as the early Eocene) to the Late Pleistocene. They were long classified in Struthioniformes (the ratites), but are now usually classified as a type of gigantic fowl (Galloanserae). Dromornithids were part of the Australian megafauna. One species, Dromornis stirtoni, was 3 m (9 ft 10 in) tall, making them among the largest birds ever. Only a single species, Genyornis newtoni survived into the Late Pleistocene. They are thought to have been herbivorous.