The first direct evidence that humans played a substantial role in the extinction of the huge, wondrous beasts inhabiting Australia some 50,000 years ago, in this case a 500-pound bird, has been discovered by a team led by University of Colorado at Boulder (CU-Boulder) scientists. The flightless bird, known as Genyornis newtoni, was nearly 7 feet tall and appears to have lived in much of Australia prior to the establishment of humans on the continent ~50,000 years ago, said CU-Boulder Professor Gifford Miller, Ph.D. The evidence consists of diagnostic burn patterns on Genyornis eggshell fragments that indicate humans were collecting and cooking its eggs, thereby reducing the birds' reproductive success. "We consider this the first and only secure evidence that humans were directly preying on now-extinct Australian megafauna," said Dr. 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." An open-access article describing this new work was published online on January 29, 2016 in Nature Communications. The article is titled “Human Predation Contributed to the Extinction of the Australian Megafaunal Bird Genyornis newtoni ~47 ka.” In analyzing unburned Genyornis eggshells from more than 2,000 localities across Australia, primarily from sand dunes where the ancient birds nested, several dating methods helped researchers determine that none of the eggshells were less than ~45,000 years old. Burned eggshell fragments from more than 200 of those sites, some only partially blackened, suggest pieces were exposed to a wide range of temperatures, said Dr. Miller, also a professor in CU-Boulder's Department of Geological Sciences.
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