Ancient Australian Egg Eaters Helped Extinction of ‘Thunderbirds’

Ancient Australian Egg Eaters Helped Extinction of 'Thunderbirds'

Genyornis, or “thunderbirds”, became extinct about 47,000 years ago, shortly after humans arrived in present-day Australia.


australian museumA huge flightless bird, Genyornis was a mihirung nicknamed a “thunderbird”.

Many modern humans enjoy eating eggs. The same was true for ancient people living in Australia, and a new study suggests they stole and ate as many eggs of huge flightless birds called Genyornis that they drove the small-winged wonders to extinction.

“Eggshell fragments with unique burning patterns consistent with human activity have been found in different locations across the continent,” Gifford Miller, geoscientist at the University of Colorado and co-author of a paper about birds published in Proceedings of the National Academy of Sciencessay it University of Cambridge.

He added: “This implies that early humans did not necessarily hunt these huge birds, but regularly raided nests and stole their giant eggs for food. Human overexploitation of eggs may well have contributed to Genyornis extinction.”

Also known as mihirunga, the birds were about six times the size of an emu, according to Science. Over six feet tall and over 500 pounds, they once roamed the ancient continent of Australia alongside marsupial lions and giant kangaroos. Then, about 47,000 years ago, they disappeared.

Scientists have long suspected that humans had something to do with their extinction. After all, the first humans started arriving in Australia around 65,000 years ago, shortly before Genyornis faded away. But it took studying ancient eggs to understand the role people played in the birds’ slow demise.

According to Science, researchers began linking burnt old eggshells to human consumption and thunderbirds in 2016. They speculated that humans stole the birds’ nests, driving the giant Genyornis to an untimely death.

“A lot [of shells] had been burned, implying human consumption,” Miller told Science. “That would have been the first sure evidence of direct predation.”

But there was just one problem. Although some scientists believed the burnt eggs definitely belonged to the thunderbirds, and thus offered evidence of humans’ role in their extinction, others argued that the eggs could have belonged to a completely different species.

Genyornis prosecutedGenyornis prosecuted

Peter TruslerA depiction of a thunderbird driven from its nest by a Megalania lizard.

Specifically, some thought the ancient egg fragments might belong to an extinct bird called Program, or “giant malleefowl”. These birds were much smaller, around 11 to 15 pounds, and were comparable to large turkeys. The eggs in question, argued those who believed they were laid by Programwere too fragile to be Genyornis eggs.

“We needed an independent way to demonstrate that the shells belonged to a giant bird,” Miller told Science.

It was easier said than done. Scientists attempted to extract DNA from the eggs, which could have provided a quick answer to where they came from. But thousands of years in the hot Australian sun made that plan unworkable.

“The shells were too old and the climate is too hot,” Beatrice Demarchi, a proteomics expert from the University of Turin who helped identify the eggs, told Science.

Instead, the researchers decided to try a different technique. According to the University of Cambridge, they extracted a different type of “biomolecule” protein, which allowed them to compare the DNA sequence to living birds.

“The Program was related to today’s megapodes, a group of birds in the galliform lineage, which also contains ground feeders such as chickens and turkeys,” said Demarchi at the University of Cambridge. “We found that the bird responsible for the mystery eggs appeared before the galliform lineage, which allowed us to rule out the Program hypothesis.

“This supports the implication that the eggs eaten by early Australians were laid by Genyornis.”

Miller explained that the former probably didn’t fight with the birds — they just stole their nests. Eventually, the humans ate more eggs than the birds could lay.

“It’s entirely possible that humans managed to drive the birds out of the nest,” Miller told Science. “The most effective way to cause an extinction is to capture the young.”

That said, questions about thunderbirds remain. Why did such huge poultry lay such small and fragile eggs? Further study on this issue is needed.

After reading about the extinction of Australia’s thunderbirds, learn how ancient people domesticated dangerous cassowary birds. Or find out how the ancient Egyptians hunted crocodiles so they could mummify them.