California condor

With only 22 California condors left in 1982, biologists made a drastic call: by 1987 every remaining wild bird had been taken into captivity, leaving none flying free. Releases of captive-bred condors began in 1992. At the end of 2025 the world population stood at 607, with 392 flying wild. That is a genuine comeback for North America's largest land bird, but not yet a self-sustaining one, and the species is still Critically Endangered. Lead from spent ammunition remains the leading known cause of death, and research has found that without continued releases and treatment of poisoned birds the wild population would slide back toward extinction.