[6][7] The scientific name Dromornithidae derives from the Greek words δρομαίος, dromaios ("swift-running") and ὀρνις, ornis ("bird").

The latest idea on dromornithid relationships, based on details of the skull, is that they evolved early in the lineage that includes waterfowl (Anseriformes).

[10] Worthy et al. (2017) incorporated several new taxa and character traits into existing matrices of Galloanserae resulted in several of their phylogenies to support this grouping.

[17] Two year later, Mclnerney, Blokland and Worthy redescribed the skull morphology and phylogenetic affinity of the dromornithid Genyornis newtoni, finding Dromornithidae as members of Anseriformes, closely related to screamers from South America.

Dromornis planei (the "demon duck of doom") and Genyornis newtoni (the "mihirung") were more heavily built, stood about 2 to 2.5 m (6.6 to 8.2 ft) tall and probably reached weights of 220 to 240 kg (490 to 530 lb).

Cave paintings thought to depict this bird are known, as are carved footprints larger than those considered to represent emus.

Many scientists believe that human settlement and hunting were largely responsible for the extinction of dromornithids, as well as many other species of the Australian megafauna.

After the man had climbed back up, it was found that the projecting object was the fossilised long bone of a large bird.

In 1892, E. C. Stirling and A. H. C. Zietz of the South Australian Museum received reports of large bones in a dry lake bed in the northwest of the state.

Peter Murray and Dirk Megirian of Australia's Northern Territory Museum recovered enough skull material of Bullockornis to give a good idea of what that bird's head looked like.

However, biomechanical analysis of the attachments and presumed sizes of the muscles suggest that dromornithids might have been able to run much faster than originally thought, making up for their less than ideal form with brute strength.

[citation needed] Rich deposits of Dromornis stirtoni specimens, containing two forms has been determined to be evidence of sexual dimorphism within that species, the largest known.

[26] This belief is based on: Functional interpretations by researchers Warren Handley and Trevor Worthy suggests that dromornithids were specialised herbivores that likely possessed well-developed stereoscopic depth perception, were diurnal and fed on soft browse such as new growth, soft leaves, and fruit.

Musculature for operation of the bill is “surprisingly limited", suggesting that these birds were not capable of a particularly forceful bite.

Most of the records of dromornithids come from the eastern half of the continent, although fossil evidence has also been discovered in Tasmania and Western Australia.

There are foot impressions from the Early Eocene in southeastern Queensland (Redbank Plains Formation) that may be referable to dromornithids.

[27] The most recent evidence, of Genyornis newtoni, has been found at Cuddie Springs in north-central New South Wales and dated at 31,000 years old.

It is hypothesized that the arrival of the first humans in Australia (around 48–60 thousand years ago) and their hunting and landscape-changing use of fire may have contributed to the disappearance of the megafauna.