The population steadily declined during the 20th century until there were only 27 California condors known to exist in the world.

The last of the free-flying condors were taken into captivity in 1987 to avoid additional mortality and to preserve as much diversity of the gene pool as possible. Reintroduction of condors into the wild began in early 1992 and continues today, with the population of more than 330 in the wild.

Lead poisoning from spent ammunition is the number one cause of death among adult California condors in the wild. Condors also pick up and feed their young small objects left behind by humans, such as pieces of glass and metal, and have been known to accidentally drink poison like antifreeze. Human development has significantly degraded or destroyed the habitat condors require for foraging, nesting and roosting.