The researchers from Stanford University and four other institutions base their conclusion on the feeding behavior of modern and early condors and their potential prey. Writing in the Nov. 7 online edition of the Proceedings of the National Academy of Sciences (PNAS), the research team concludes that whales and seals have been an integral part of the condor's diet since the last Ice Age, and that current efforts by the United States government to restore wild condor populations could be enhanced if captive-bred birds are released near marine mammal breeding grounds along the West Coast.
"Condors eat carrion, they don't kill for food," says C. Page Chamberlain, lead author of the PNAS study and chair of Stanford's Department of Geological and Environmental Sciences. "What we're proposing is a conservation strategy to train them to start eating dead seals and sea lions, whose populations are coming back along the California coast."
Standing nearly 5 feet tall and boasting a nine-and-a-half-foot wingspan, the California condor (Gymnogyps californianus) is the largest bird in North America. Thousands are believed to have inhabited the continent during the last Ice Age, their range extending from British Columbia to Baja California and east into Texas, Florida and New York.
Fewer than 300 are alive today, the majority recently bred and hatched in zoos as part of the U.S. Fish and Wildlife Service California Condor Recovery Program--a federally supported effort is to establish self-sustaining condor populations in the wild. Since 1992, program affiliates have released a total of about 130 captive-bred birds in wild areas of California, northern Mexico and near the Gra