These birds belong to the order Anseriformes (Anseriformes) and were close relatives of modern ducks and geese. At the height of Dromornis stirtoni was more than 3 meters long and weighed about 500 kg. It lived in Australia and the Middle Miocene, at about 15 million years ago. It was probably omnivorous. Currently Dromornis stirtoni and Aepyornis maximus, are considered the largest and most severe in the history of the bird fauna. But recently, leontologists have found a skull of a previously unknown species, which was given the name ( Kelenken guillermoi ).
They are sometimes referred to as Mihirung birds. 'Mihirung paringmal' is an Aboriginal word from the Tjapwuring people of Western Victoria and it means 'giant bird'. Although they looked like giant emus, the Dromornis are more closely related to geese.
Dromornis stirtoni was three metres (10 feet) tall and weighed half a ton (500 kilos). It inhabited subtropical open woodlands in Australia during the Late Miocene and may have been carnivorous. It was heavier than the Moa and taller than Aepyornis . Due to the poor fossil record of Dromornis australis (the type species of the genus) and the large time gap between the two Dromornis species, D. stirtoni may eventually be reassigned to the genus Bullockornis.
This species had a long neck and stub-like wings, rendering it flightless. Its legs were powerful, but it is not believed to have been a fast runner. The bird's beak was large and immensely powerful, leading early researchers to believe that it was used to shear through tough plant stalks. However, recently others have argued that the size of the beak suggests that the bird was a carnivore.
Dromornis are part of a family of giant birds called Dromornithidae that lived from 15 million years ago until less than 30,000 years ago. Australia had been separated from the big southern landmass of Gondwana for millions of years by this time. The animals of Australia had evolved very slowly in almost complete isolation from the animals of other continents. There were forests and a permanent water supply at Alcoota where the Dromornis birds lived, although the climate was very unpredictable.