The masked bobwhite (Colinus virginianus ridgwayi) had vanished from its small range in Southern Arizona by around 1900, due to habitat changes brought on by cattle grazing. The masked bobwhite was thought to be extinct by the 1930's. Then, in 1964, Steve Gallizioli, an Arizona Game and Fish biologist, and naturalists Jim and Seymour Levy of Tucson, rediscovered a small population in Sonora, Mexico and a program to re-introduce the bird was initiated. Introductions of pen raised birds on grazed cattle ranches failed. Then the Endangered Species Act made possible the acquisition of the Buenos Aires property in the mid-80's, cattle were removed from the grasslands, and funding was made available to begin a larger restoration program.
Still, after the rearing and release of more than 25,000 masked bobwhite quail, success has eluded the FWS. Mortality rates after release are over 90% - not surprising, since quail mortality year to year is high due to predation. While the FWS says in official documents that perhaps 100 to 200 wild birds live in the Buenos Aires grassland, Bonnie Swarbrick of the FWS at Buenos Aires told me there may be as few as 50 wild birds established at the refuge.
Sometimes what is undone cannot later be remedied, despite the best of intentions.