A new scientific report reveals that early humans were responsible for the extinction of an ancient giant and flightless bird in Australia by eating their eggs.

The study, which was conducted by a team of Australian and American scientists led by University of Colorado Boulder Prof. Gifford Miller, analyzed burn patterns on massive eggshell fragments of a bird species dubbed Genyornis newtoni, report LiveScience.

Based on their findings, scientists concluded that the eggshell fragments were discarded by humans in and around transient fires that they used to cook the eggs tens of thousands of years ago. As a result, by collecting and cooking Genyornis' eggs, humans reduced the birds' ability to reproduce and populate.

Researchers came to this conclusion after collecting and examining burnt eggshell fragments from more than 200 sites. The eggshell fragments were found in small, 10-foot clusters, and exhibited signs of being cooked in fires up to 1,000 Fahrenheit.

"We can't come up with a scenario that a wildfire could produce those tremendous gradients in heat," Miller said, in a statement. "We instead argue that the conditions are consistent with early humans harvesting Genyornis eggs, cooking them over fires, and then randomly discarding the eggshell fragments in and around their cooking fires."

Researchers believe the eggshells are between 54,000 to 44,000 years old, which is around the same time frame that humans are believed to have arrived on the continent. Unlike previous studies, scientists are now sure that almost 85 percent of species became extinct after humans populated the land.

The study, which was published Friday in the science journal Nature Communications, also found that Genyornis weighed about 500 pounds and stood about 7 feet tall. As a result, their massive eggs would have likely weighed 3.5 pounds.

"We consider this the first and only secure evidence that humans were directly preying on now-extinct Australian megafauna," said Miller, associate director of CU-Boulder's Institute of Arctic and Alpine Research. "We have documented these characteristically burned Genyornis eggshells at more than 200 sites across the continent."

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