The Sonoran pronghorn once roamed vast areas of the Sonoran Desert, but is now limited to three small populations: two in Mexico and one in southwestern Arizona. In 1991, Arizona’s population dropped to just 250 animals. In the 1990s a severe drought set off an even more precipitous decline; by 2003, only 21 animals remained.
Federal land managers and the Arizona Game and Fish Department (AGFD) resolved to save the U.S. species by establishing a captive breeding program. The Department of Defense (DOD) provided funds and program planning, the AGFD managed day-to-day operations, and the USDI Fish and Wildlife Service furnished the breeding location.
The Sonoran pronghorn is shy; land managers worried that the animals might die from stress during capture, transportation, and con. nement. Also, they were not sure if the enclosure would ward off predators. If they failed, it could lead to extirpation of the species.