One of three condor chicks raised in wild nests was found dead by scientists Sunday after the big bird's radio transponder emitted a "mortality signal," according to Ventana Wildlife Society senior wildlife biologist Joe Burnett.

Biologists from the society's condor recovery project in Big Sur found the lifeless body of a wild California Condor chick lying in thick brush beneath a tall stand of redwoods, only a half mile from its coastal nest site.

The wild male chick, known as No. 475, was recently observed making short flights in the nest area, which is normal behavior for a 9-month-old condor, Burnett said.

The bird was wearing a radio tag that alerted biologists there was trouble when it began emitting a mortality signal Sunday morning, he said.

Ventana biologists Mike Tyner and Jessica Koning tracked the signal through thick brush into a very steep coastal ravine and finally located the chick lying motionless on the ground. Condor 475 will be examined more closely at San Diego Zoo's Pathology Lab, Burnett said, adding that the cause of death is unknown at this time.

Condor 475 is one of three wild chicks produced by the condor flock in Big Sur this year. The other two surviving wild chicks, Nos. 470 and 477, continue to grow strong and are a little further along in development.

"It's always very difficult to lose such a young condor," Burnett said. "We really wish all of the chicks could make it."

Last year, the Big Sur flock produced two wild condor chicks and one survived, an expected 50 percent survival rate for condor chicks in the wild.

Ventana Wildlife Society biologists believe that there could be as many as four wild condor chicks just in Big Sur in 2009.

The condor population reached an all-time low of 22 in 1982. Through captive breeding and subsequent releases, the total condor population now stands at 326. In central California, there are 47 free-flying condors, three of them wild-born.

The Ventana Wildlife Society is the only not-for-profit organization releasing and managing condors in California. The Society works with the U.S. Fish and Wildlife Service, Pinnacles National Monument, state Department of Parks and Recreation, state Department of Fish and Game, Los Angeles Zoo, San Diego Wild Animal Park, U.S. Forest Service and others.