Endangered California condors roosting in western Sierras for first time in nearly 40 years
BLUE RIDGE NATIONAL WILDLIFE REFUGE, Calif. – For the first time in nearly forty years endangered California condors are roosting at Blue Ridge National Wildlife Refuge (NWR) in Tulare County, California.
“Blue Ridge was created specifically for California condors, and to see them roosting there once again is a historic moment for us. As we grow the California condor population, their distribution continues to expand into their former range, which includes the Sierra foothills,” said Joseph Brandt, supervisory wildlife biologist with the U.S. Fish and Wildlife Service’s (Service) Hopper Mountain National Wildlife Refuge Complex (NWRC) in Ventura, California.
Blue Ridge was identified as critical habitat in the 1970s because of its importance as a historical roost for condors and its proximity to areas where condors once foraged and nested in the western Sierras. Several years later the Service acquired and established the land as Blue Ridge NWR. Condors were routinely observed in the southern Sierra foothills as recently as the 1970s, however, by 1982 the wild population was reduced to 22 birds, all of which were eventually trapped and brought into captivity to prevent extinction of the species.
In 1992 the Service and partner organizations began releasing condors into the wild, and today there is a wild population of 160 condors in California. They are found in the mountains of Monterey, San Benito, San Luis Obispo, Santa Barbara, Ventura, Los Angeles and Kern counties, and most recently in the western foothills of the Sierra Nevada Mountains in Tulare and Fresno counties.
Biologists with Hopper Mountain NWRC first tracked condors on Blue Ridge NWR in June, and have since documented seven condors roosting there. Roosting means that a bird spends the night in a location. Condors are very social birds and roost together in groups to share information about foraging locations and roosting together can provide protection from predators.
“As the population range expands, condors are beginning to make more frequent foraging flights into the southern Sierras and now using roost sites like Blue Ridge. It’s also likely condors will resume nesting in this region, in the cavities found in rock formations or in old growth sequoia trees,” said Brandt.
Biologists attach Global Positioning System (GPS) transmitters to many condors to closely track the birds’ movement, which can mean traveling hundreds of miles in a single day. GPS data produced by these transmitters are used to identify important habitat, locate condor nesting and feeding activity, and finding sick or injured condors, or condors that have died in the wild.
Condors inhabiting more of their former range reinforces biologists hopes that a wild condor population is established in California and will continue to grow as the species recovers, but it also highlights the fact that range expansion could also mean exposure to additional threats.
“As condors continue to expand northwards we will have to examine how we manage the growing population, how we engage with the local communities to inform them about the threats to the birds, and what they can do to contribute to the recovery of the species,” said Dave Ledig, project leader, Hopper Mountain NWRC.
Lead poisoning, caused by condors feeding on carcasses containing lead bullet fragments, is the number one killer of California condors. Research shows that lead poisoning is a serious health problem for both wildlife and humans, and the Service is working with partner organizations to share information within the hunting community about non-lead alternatives.
“Hunters are continuing their proud tradition of wildlife conservation by using these non-lead alternatives,” said Ledig.
Blue Ridge is the smallest refuge of the Hopper Mountain National Wildlife Refuge Complex and is located in the foothills of the western Sierras. Hopper Mountain NWRC oversees Bitter Creek, Hopper Mountain and Guadalupe-Nipomo Dunes National Wildlife Refuges, conserving more than 20,000 acres of land in central and Southern California. The National Wildlife Refuge System manages a national network of lands and waters set aside to conserve America’s fish, wildlife, and plants.
- Hits: 3212