Local partnership increases healthy desert bighorn sheep populations across southeastern Arizona

Desert bighorn sheep populations across southeastern Arizona have greatly increased thanks to an ongoing partnership between the BLM, Arizona Game and Fish Department (AGFD), and the Arizona Desert Bighorn Sheep Society (ADBSS). Through the partnership, sheep from large herd areas on BLM-managed public land are relocated to lesser populated areas with similar land features.

A Fall 2018 relocation from the Silver Bell bighorn sheep population in the Ironwood Forest National Monument is an example of a successful project made possible by this partnership. This herd, which was one of the few remaining historical populations of bighorn sheep in southeastern Arizona, was reduced in number by disease in 2003. Cooperative efforts by the BLM, AGFD, ADBSS, and private landowners ensured the population survived.

In October 2003, 4,800 domestic goats wandered onto state trust land near the Ironwood Forest National Monument with 400 to 500 escaping and trespassing into the monument. “Those escapees (goats) carried two diseases that infected and dramatically reduced the native desert bighorn sheep population in the monument from about 80 to 50 in a matter of months,” said AGFD Wildlife Science Coordinator Jim Heffelfinger. Because of quick action by ADBSS and other partners coordinated by the AGFD and BLM’s Tucson Field Office, the goats were removed and the remaining sheep were treated with medications.

Over subsequent years, the BLM and the AGFD worked together to construct a new wildlife water catchment and rebuild a number of other wildlife water catchments in the monument. “Because of these efforts, the bighorn sheep population in the monument soared to more than 200 animals by 2017, and provides an abundant source of desert bighorns for relocation to other historic habitat in southern Arizona,” said retired BLM Natural Resource Specialist Darrell Tersey.

In November 2018, the AGFD spearheaded an effort to capture 30 bighorns and transport them to the Picacho Mountains on BLM-managed public land. The land was a historic range for the sheep until the 1930s when their population declined due to over hunting prior to the creation of state hunting regulations. The release area was only 17 miles away as the crow flies, but impossible for the sheep to reach because of constructed barriers including an interstate highway, railroad tracks, and a large canal fenced on both sides with 10-foot tall chain link fencing.  

The capture crew was efficient, one time bringing as many as five sheep at once to the volunteers to be checked by veterinarians and ear tagged. AGFD staff placed radio collars on ten of the desert bighorn sheep. 
“The capture was planned to take two days, but everyone stepped up and made the target of 30 sheep ready for transport by the end of the first day,” said AGFD Region 5 Terrestrial Wildlife Specialist Rana Tucker. The bighorn sheep, including those with radio collars, were transported to the new location and released.  The radio collars will provide information on sheep movement within the habitat.

The AGFD’s Tucson office regularly collects the collar data and shares it with the BLM and other partners to document the status of the native wild bighorn sheep moved to the historic use areas on public lands. Six months later, the data from the relocation to BLM lands indicates that none of the collared bighorn sheep have died or moved elsewhere.

Typically, second and third translocations are necessary to get the bighorn sheep close to a self-sustaining level with good genetic diversity. In this case, because they are doing so well, the AGFD may not have to do a third translocation to this area.

Partnerships like this one ensure that desert bighorn sheep will continue to thrive in southeastern Arizona and provide a wealth of hunting opportunities and wildlife viewing opportunities now and into the future. 
The fifty-year strong partnership supports the Department of the Interior’s (DOI) Secretarial Order 3356 that directs bureaus to coordinate with states, tribes and territories in planning and decision-making that impacts hunting, fishing and recreational shooting access. It also supports Secretarial Order 3362 that directs DOI bureaus to evaluate how their lands can contribute to State or other efforts to improve the quality and condition of priority big game winter and migration corridor habitat and improve hunting and fishing access, opportunities, and game species habitat and population management directives.

Story by Darrell Tersey, retired BLM Tucson Field Office Natural Resource Specialist; June Lowery, BLM Gila District Public Affairs Specialist; Rana Tucker, Arizona Game and Fish Department Region 5 Game Specialist.
Photos courtesy of the Arizona Game and Fish Department.