\A genetic analysis indicated humans largely drove Carolina parakeets to extinction, reports National Geographic.
Researchers led by Universitat Pompeu Fabra's Carles Lalueza-Fox sequenced the genome of the Carolina parakeet (Conuropsis carolinensis), which was native to the US until its last living member died at the Cincinnati Zoo in 1918. They compared its genome to that of its closest living relative, Aratinga solstitialis, and other previously sequenced birds. As they report in Current Biology, the researchers uncovered two key alterations to the C. carolinensis genome affecting the SLC25A4 and SLC25A5 genes that have enabled it to eat cockleburs, despite the toxin the plant produces.
But the researchers did not find any genetic evidence of population decline such as large runs of homozygosity, suggesting that the Carolina parakeets' decline was due to human interference. "The inference is that this bird was not subjected to a very long demographic decline for thousands of years, it was something very quick," Lalueza-Fox tells the BBC.
The University of Connecticut's Kevin Burgio tells Audubon Magazine, though, that additional analyses are needed. "I am not trying to say that other human-related problems such as habitat loss, being collected in the wild for the pet trade, or being shot as crop pests didn't play a role," he notes. "It's very likely that it was a combination of all of these factors that eventually led to their extinction."