Establishment of a desert bighorn sheep population to the Fra Cristobal Mountains, New Mexico, USA

Summary

Desert bighorn sheep (Ovis canadensis mexicana), listed as endangered in New Mexico since 1980 after over-hunting and livestock-borne disease decimated populations, were reintroduced to the privately owned Fra Cristobal Mountains starting in 1995 through a collaboration between the New Mexico Department of Game and Fish and Ted Turner's Armendaris Ranch, releasing 13 rams and 24 ewes initially and seven more radio-collared rams in 1997. When six of those seven collared rams were killed by mountain lions within 18 months, revealing predation rather than disease as the dominant threat to small desert bighorn populations, the Turner Endangered Species Fund redesigned the restoration around intensive, risk-graded lethal cougar control, prioritizing removal of resident females with dependent young, informed by continuous telemetry and camera-trap monitoring; 34 cougars were removed between 1997 and mid-2011. By May 2011 the Fra Cristobal herd had grown to 200-220 sheep and spawned a second population of 65-75 in the nearby Caballos Mountains, together the largest bighorn meta-population in New Mexico and over 40% of the state's total, prompting the state to remove the species from its endangered list in November 2011. The program then began serving as a donor population, translocating 16 ewes elsewhere in October 2011 and, from 2012, supporting a sustainable trophy-ram hunting program that generated $165,000 in permit sales in its first year. Difficulties included balancing research with population growth and managing the controversy inherent in lethal predator control. The project rates itself highly successful, crediting sustained interagency collaboration and a restoration design built around the true, empirically identified cause of mortality.