It is not clear to what degree Dromornithidae were carnivores. The massive, crushing beaks of at least of some species suggest that they were a combination of predators and scavengers, much like today's hyenas. Their closest living relatives are waterfowl.
A study has been performed in which more than 700 Genyornis eggshell fragments were dated. Through this, it was determined that Genyornis declined and became extinct over a short period—too short for it to be plausibly explained by climate change. The authors considered this to be a very good indication that the entire mass extinction event in Australia was due to human activity, rather than climate change.
In May 2010, archaeologists announced the rediscovery of an Aboriginal rock art painting, possibly 40,000 years old, at the Nawarla Gabarnmung rock art site in the Northern Territory, that depicts two of the birds in detail. Late survival of Genyornis in temperate south west Victoria has also recently been suggested, based on dateable Aboriginal traditions.