California condors

Abstract

The California condor ( Gymnogyps californianus ) is a member of the vulture family. With a wingspan of about 3 m (9 ft) and weighing about 9 kg (20 lb), it spends much of its time in soaring flight visually seeking dead animals as food. The California condor has always been rare (Wilbur 1978; Pattee and Wilbur 1989). Although probably numbering in the thousands during the Pleistocene epoch in North America, its numbers likely declined dramatically with the extinction of most of North America's large mammals 10,000 years ago. Condors probably numbered in the hundreds and were nesting residents in British Columbia, Washington, Oregon, California, and Baja California around 1800. In 1939 the condor population was estimated at 60-100 birds, and its home range was reduced to the mountains and foothills of California, south of San Francisco and north of Los Angeles. Conservation to halt the condor's decline included establishing the Sisquoc (1937) and Sespe (1947) condor sanctuaries within the Los Padres National Forest, obtaining fully protected status under California Fish and Game Code (1953), placement on California's first state endangered species list (1971), and, finally, being listed by the federal government under the Endangered Species Act of 1973 (Wilbur 1978). The success of these efforts could not be judged, however, because verifiable status and trends data did not become available until 1982. By using these data, we confirmed the decline in condor numbers over the past 50 years was even greater than thought.