On the brink of extinction, saved by a captive-breeding program, the condor population has grown from just 22 birds in 1982 to 289 today; 135 are in the wild and more are released every year.

Even so, condors have failed to gain a secure foothold in the hills and deserts of California and Arizona because of lead poisoning, the most often diagnosed cause of death, environmentalists say.

Environmental groups say the most likely source is condors' eating of game that was shot by hunters using lead bullets. Frustrated that most hunters have not switched to substitutes, the Natural Resources Defense Council (NRDC) and other groups notified California officials in July that they will sue under the Endangered Species Act to force a ban.