BMGR pronghorn get help to grow population

  • Published
  • By Teresa Walker
  • 56th Fighter Wing Range Management Office
A recent ruling by U.S. Fish and Wildlife Service has authorized construction of another semi-captive breeding facility for the Sonoran pronghorn in the Kofa National Wildlife Refuge with the goal of establishing a second population of the endangered animal. Future plans for an additional population on a nonoperational portion of the Barry M. Goldwater Range were also included in the final ruling.

In 2002, approximately 18 Sonoran pronghorn managed to survive a severe drought and were in danger of becoming extinct. Today they number 100-plus, largely because of a captive breeding enclosure on the Cabeza Prieta National Wildlife Refuge and the commitment of several federal and state agencies.

The endangered Sonoran pronghorn antelope inhabits the southwestern Arizona BMGR that encompasses more than 1.7 million acres and is one of the nation's largest military training reservations. The range stretches from Yuma east beyond Gila Bend and from Interstate 8 south to the Cabeza Prieta National Wildlife Refuge.

The 56th Fighter Wing Range Management Office at Luke Air Force Base has land management responsibility for more than a million acres on the eastern portion of the range and plays a fundamental role in Sonoran pronghorn management and recovery actions.

Aaron Alvidrez, 56th FW RMO biologist, said the first move will include 11 animals from the original enclosure on the Cabeza to the new enclosure in the Kofa after it's built.
"Ten breeding females and one male will initially be moved from the Cabeza to the new breeding enclosure next winter," he said. "The Kofa pen will be half the size of the Cabeza pen; there is no need for it to be as large or have as many animals because we'll be releasing smaller numbers. We anticipate up to 20 yearlings to be released from the facility within a couple of years."

The 56th FW signed on as a cooperating agency in the reintroduction of the species, and in the future, a third population could be established within the boundaries of the eastern BMGR in an area known as "Area B." Animals would again be moved from the Cabeza enclosure to establish this population.

The boundaries of the Sonoran pronghorn have been severely reduced through natural occurrences and human activities, which makes them more vulnerable. The species needs wider distribution to attain the long term resilience necessary for recovery, and ultimately, delisting from the endangered species list.

These two new populations of animals are designated as "experimental, nonessential," under the Endangered Species Act rule, "Section 10(j)." This designation allows greater flexibility in reintroducing new populations within the species' historical range and means that these animals are not essential for their continued existence. The process to make these determinations took more than two-and-a-half years.

"Establishing two new Sonoran pronghorn populations will advance recovery for one of North America's most imperiled land mammals," said Benjamin Tuggle, U.S. Fish and Wildlife Service Southwest Region director. "Through the continued, far-sighted efforts of conservation biologists, numerous federal land managers, the U.S. Air Force, Native American Tribes and the Arizona Game and Fish Department, the pronghorn will now be returning to a portion of their historical habitat in the U.S."

According to Mr. Alvidrez, the Section 10(j) experimental designation has been used before with the Aplomado falcons in Texas, and in Arizona, the California condor and the Mexican gray wolves have been reintroduced with success, so the outlook for the Sonoran pronghorn is exceptionally good.

"I am definitely proud of the positive relationships the Air Force has established with the other agencies with respect to the recovery of the Sonoran pronghorn," he said. "We've all worked so hard and we fully expect these experimental populations to flourish. Each fawn that's born is the result of our commitment to the recovery of this animal."

The experimental populations are not expected to impact military operations, though the Kofa is bordered on three sides by the Army's Yuma Proving Ground. Area B is in the portion of the eastern BMGR that is open to the public and air-to-ground military operations are not conducted there.

"The reintroduction of these experimental populations of the Sonoran pronghorn is a testament to the commitment of the Air Force to integrate environmental management at all levels," said Brig. Gen. J.D. Harris Jr., 56th FW commander. "This is an exciting opportunity for the Air Force, our federal and state partners, and the greatest benefit is for this endangered species to propagate in protected enclosures."

The U.S. Fish and Wildlife Service contributed portions of this article.