One of four baby female Andean condors died while being driven overnight to remote mountain cliffs for an experiment that could lead to the return of California condors to the wild, officials said Saturday.

Two 4-month-old chicks born and raised at the San Diego Wild Animal Park were driven to the Los Angeles Zoo to rendezvous with another chick born at the zoo and one born at the U.S. Fish and Wildlife Service's Patuxent Wildlife Research Center in Laurel, Md.One of the four chicks died during the drive through the rugged back country, Fish and Wildlife Service spokeswoman Diane Hoobler said Saturday.

The chicks were placed in a plywood box inside a larger net enclosure where they will spend the next several months. They were driven by van to cliffs pocked by caves within the 60,000-acre Hopper Mountain National Wildlife Refuge, part of the Sespe Condor Sanctuary in the Los Padres National Forest, about 30 miles north of Ventura.

The birds, which have never seen humans, will be kept in the box and net enclosure for several months while being monitored by a team of biologists through one-way glass. They will be released when the youngest is able to fly, estimated to be in December. After two years of monitoring in the wild, the birds will be recaptured.

The experiment will allow biologists to evaluate techniques that could be used to re-establish a wild population of the nearly extinct California condor. Only 28 California condors remain in the world, all in zoos. The last known free-flying bird was captured in 1987.