Saving a Species: The Sonoran Pronghorn

  • Published
  • By By Darlene Seltmann
  • 56th Range Management Office

It’s no secret that the Barry M. Goldwater Range, located in the southwest region of Arizona, is used for training the world’s greatest fighter pilots and combat-ready Airmen. But what most don’t often think about are the efforts behind maintaining and conserving the 1.7-million-acre piece of land and its inhabitants.

Dec.12-13, agencies from across Arizona joined together for one common cause – the preservation of the Sonoran pronghorn.

In 2002, after a year of severe drought, the Sonoran pronghorn population in the United States plummeted to a mere 21 individuals.

The following year, seven of the remaining animals were gathered and placed in a 640-acre pen on Cabeza Prieta National Wildlife Refuge in an effort to facilitate captive breeding. In a binational effort the El Pinacate Biosphere Reserve in Mexico gave six of their Sonoran pronghorn to be added to the pen to assist with genetic diversity. The captive breeding pen continues but is viewed as a temporary measure.

Each year in December, Arizona Game and Fish Department, U.S. Fish and Wildlife Service, Bureau of Land Management, National Park Service, Department of Defense and other various organizations and agencies participate in the Sonoran pronghorn capture and release operation.

“Pronghorn are gathered from the captive breeding pen and temporarily put into large fenced and padded area, called a boma, until they can be processed and then released,” said Aaron Alvidrez, 56th Range Management Office wildlife biologist. “When pronghorn are taken for processing they are examined by a veterinarian then blood and fecal samples are taken and vaccinations are given. New pronghorn also receive ear tags and radio collars.”

Once the pronghorn have been processed, they are either selected to go back into the captive breeding pen or they are relocated to other release sites. This year, the pronghorn were transported to the BMGR, Organ Pipe Cactus National Monument, and Yuma Proving Grounds.

“This year we processed a total of 70 pronghorn,” Alvidrez said. “We were successful in our objectives by relocating 22 pronghorn from the CPNWR captive breeding pen to the holding pens for release into the wild.”

Nine new pronghorn, seven buck, and two does were released onto the BMGR East in the temporary holding pens.

They will be fed and monitored for about three weeks, giving them the opportunity to acclimate to their new environment, before being released onto the Range to roam freely.  

Alvidrez has been the Air Force representative on the Sonoran pronghorn recovery team since 2006 and has assisted with the capture and release every year.

“We are proud to be active members of the Pronghorn Recovery Team and our everyday management of the herd on the BMGR East,” said Charles Buchanan, 56 RMO director.

The Sonoran pronghorn capture and release operation is just one element of many projects that support pronghorn recovery actions. 

During the summer months, when forage is scarce, various agencies to include the 56 RMO take turns dropping off alfalfa at various locations throughout the southern Arizona desert to ensure there’s enough food for the pronghorn.

Artificial water catchments have also been constructed on the Range and other areas known to inhabit the Sonoran pronghorn.

Each morning prior to any missions on the Range, a team of wildlife biologists go out to locate the pronghorn. If there are any in the vicinity of targets, then the targets are closed for operation, and missions are moved to locations that will not impact the pronghorn.

“I consider myself really fortunate to be a part of the Sonoran pronghorn recovery program,” Alvidrez said. “We have come a long way since the 2002 timeframe when we only had an estimated 21 individual Sonoran pronghorn remaining. The most recent U.S. population survey conducted in December of 2022 estimated 211 Sonoran pronghorn within the current endangered distribution range.” 

The Sonoran pronghorn population distribution spans across multiple land agencies in Southwest Arizona. Given how large of an area the Sonoran pronghorn occupy, it takes consistent effort from various agencies throughout the year to make the recovery of this federally endangered species happen.

“The combined efforts of all agencies involved directly contribute to the overall health, well-being, and population growth of this unique endangered species roaming throughout the BMGR and the Sonoran Desert,” said Buchanan. “Our resource stewardship is at the forefront of supporting the military flying mission and I’m extremely proud of our team and the job they do but it’s the teamwork and the outstanding partners and relationships that we owe much of our success to.”