The Ilbandornis was an ostrich

Ostrich

The Ostrich is one or two species of large flightless birds native to Africa, the only living member of the genus Struthio. Some analyses indicate that the Somali Ostrich may be better considered a full species apart from the Common Ostrich, but most taxonomists consider it to be a...

-sized animal, with more slender legs than other Dromornithids. The large bill of other species like Bullockornis

Bullockornis

Bullockornis, nicknamed the Demon Duck of Doom, is an extinct flightless bird that appeared to have lived in the Middle Miocene, approximately 15 million years ago, in what is now Australia....

and Dromornis

Dromornis

Dromornis is a genus of prehistoric birds. They stood 3 meters tall and weighed half a ton. Dromornis lived in Australia from the late Miocene to the early Pliocene, meaning that early humans never encountered this genus....

indicates a carnivorous

Carnivore

A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...

 creature, while the gizzard

Gizzard

The gizzard, also referred to as the ventriculus, gastric mill, and gigerium, is an organ found in the digestive tract of some animals, including birds, reptiles, earthworms and some fish. This specialized stomach constructed of thick, muscular walls is used for grinding up food; often rocks are...

 and amino acid

Amino acid

Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

 analysis of the eggs of Genyornis

Genyornis

Genyornis was a monotypic genus of large, flightless bird that lived in Australia until 50±5 thousand years ago. Many species became extinct in Australia around that time, coinciding with the arrival of humans....

indicates Ilbandornis was herbivorous

Herbivore

Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

. As yet, the diet is in debate. Both species were found at the same locality in the Northern Territory

Northern Territory

The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...

 at Alcoota Station, and dated to the Late Miocene

Late Miocene

The Late Miocene is a sub-epoch of the Miocene Epoch made up of two stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch....

.