Flightless Duck Hunted to Extinction
Terry Jones, Chair
Department of Social Sciences
California Polytechnic State University
San Luis Obispo, CA
T.: (805) 756-2523
March 6, 2008
March 6, 2008
Contact: Christina S. Johnson, email@example.com, 858-822-5334
Flightless birds are something of an evolutionary oxymoron, right up there with nonswimming fish or vegetarian carnivores. They are painfully vulnerable to extinction, Exhibit A being the dodo bird. (The obvious counterexample, the penguin, has had the survival advantage of living on the one continent uninhabited by humans.)
As it turns out, California once had its own version of a dodo bird, a flightless duck known in scientific circles as Chendytes lawi. Like the dodo bird, which inhabited the Indian Ocean island of Mauritius but not the African continent nearby, Chendytes escaped terrestrial predators, two-legged and four, by colonizing the Channel Islands. Unlike the dodo bird, Chendytes could dive and swim, which may partially explain its longevity as a species under prehistoric fire.
Archeology professor Terry Jones of Cal Poly San Luis Obispo, Judith Porcasi of the Costen Institute of Archeology at UCLA and Jon Erlandson of the Department of Anthropology at the University of Oregon have shown that prehistoric coastal peoples in California began hunting the duck about 11,000 years ago. More significantly, they hunted it for fully 8,000 years before it finally went kaput, that is extinct, about 2,400 years ago. The details of this finding, based on carbon dating of archeological remains from 14 prehistoric settlements spanning San Diego to Sonoma County, are to be published in the Proceedings of the National Academy of Sciences.
“The duck could not fly and the people were able to collect their eggs,” said Jones, whose research was funded by California Sea Grant. “This is a ‘perfect storm’ for driving an animal to extinction. I would never have thought it would take 8,000 years to wipe them out.”
Yet, it did and the duration of the duck’s demise has led Jones to doubt the validity of the “Pleistocene overkill hypothesis” – the theory that iconic Ice Age megafauna such as the ground sloth and mammoth were pushed to extinction in a blitzkrieg fashion by Clovis hunters about 13,000 years ago. In this theory, 35 genera of Pleistocene mammals are wiped off the planet in the span of 400 years.
Why would it take 8,000 years to wipe out one species of flightless bird, and why would there be virtually no archeological evidence for human hunting of extinct Pleistocene megafauna, save the mammoth, Jones said.
“We make the case it must mean the Pleistocene megafauna were wiped out some other way besides having been hunted,” he said. “If the overkill hypothesis were true, we would expect to see a more substantial record of exploitation in the archeological record. That record is not there.”
Others caution about drawing too many conclusions about Pleistocene terrestrial mammals from the history of one semi-marine duck. Paul Koch, chair of isotope biogeochemistry and vertebrate paleontology at UC Santa Cruz, said “there might not have been enough people living on the coast to drive the bird to extinction. I’d want to know the number of people living on the coast.”
Koch also believes the duck was really only vulnerable when nesting, and that it might have had some nests in remote places that effectively served as refuges for the species. “Yes, people had boats and could get to the islands but were the ducks worth going after,” he said. “They might not have been worth the effort. These people were obviously not Chendytes specialists. Otherwise, they would have gone extinct with the bird.”