Photo By James Gilbert | A Sonoran pronghorn is being released back into a 340-plus acre semi-captive breeding...... read more read more
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Five Sonoran pronghorn antelope were transferred last month from a semi-captive breeding facility in the King Valley area of the Kofa National Wildlife Refuge to a holding pen on the eastern edge of Yuma Proving Ground (YPG), where they were eventually going to be released into the wild.
YPG Wildlife Biologist Daniel Steward explained that while the initial plan had been to monitor the two female and three male pronghorns for a couple weeks before releasing them in early January, Mother Nature chose not to cooperate.
He went on to say that a storm in late December that passed through the area washed out a section of the fence of the holding pen, which allowed the five pronghorns to escape, along with four does and five bucks from another herd that had previously been placed there.
Having wandered off from the holding pen in different directions, the hope now is that all 14 of the animals will eventually join up with a pronghorn herd that has been established on the Palomas Plains, which is within the borders of the proving ground.
“This is all part of an ongoing recovery effort for the Sonoran pronghorn, which is endangered. It is an effort to basically make more land available for the recovery of the species,” Steward said. “There is a tremendous amount of habitat to the east, so we wanted to get them moving in that direction.”
The Sonoran pronghorn is an extremely rare subspecies of the pronghorn and can only be found in the deserts of southwestern Arizona and northwestern Mexico.
Once vast in numbers, man-made obstacles to food and water, droughts, wildfires, and the spread of agriculture caused its population numbers to plummet, resulting in the pronghorn being protected under a precursor to the Endangered Species Act since 1967.
Then in 2002, following one of the hottest and driest years on record, the species was nearly wiped out with all but 21 Sonoran pronghorns perishing as the result of a severe 13-month drought.
Two years later, federal and state wildlife biologists stepped up to save the species from extinction by providing them food and water and developing a captive breeding program, which has proven to be extremely successful.
Thanks to these efforts, it is estimated that there are more than 650 Sonoran pronghorn in the state now.
In preparation for December 19, 2023 capture and release operation, a number of pronghorn from the herd on the refuge were moved to a 340-plus acre semi-captive breeding pen.
Over the next several weeks those pronghorns were then conditioned to enter a three-chambered circular livestock enclosure called a boma for food and water. Eventually the doors were closed, trapping 28 inside.
On the actual day the operation was held, the pronghorns were then sorted into groups of three and herded from chamber to chamber inside the boma. The walls of the last pen were padded as a precaution.
“Pronghorns are very fragile animals so we must be very careful how we handle them and prevent them from panicking,” Steward said. “There has been a huge learning curve about how we handle them.”
Once a group of three was in the final chamber, dozens of people quickly scurried inside through a sliding gate. Some lined the walls of the chamber to prevent the animal from accidently injuring itself while others used long nets to capture them.
“The goal is to run into the boma and keep the pronghorn away from the edges of the chamber because if they hit the sides of the pen they can get hurt,” Steward said.
While working in virtual silence to reduce stress to the animal, their heads were then covered and they were held so blood could be drawn, and their temperature and scat samples taken.
Chris Lohrengel, who is the Deputy Complex Manager for the U.S. Fish and Wildlife Service’s Southwest Arizona Refuge Complex, was one of the people who went inside the boma, saying it was both exciting and dangerous.
“It gets pretty chaotic in there. I have seen people get concussions and cuts before. It is fun though,” Lohrengel said. “This is one of those things that I can’t believe we get paid for. We get to live out or dreams and come out here and play with the animals.”
He added that, “This is one of the rare success stories. What we have done here is pretty significant.”
After being caught, the pronghorns were then carried on stretchers with leg holes to veterinary stations set up under pop up tents just outside the boma, where they were vaccinated, given medical examinations, outfitted with a tracking collar, and tagged on one ear.
YPG veterinarian Capt. Jessica Martinoff said while one of the animals she tended to had a minor leg injury, the rest seemed to be in overall good health.
“It is amazing to be part of something like this, helping an endangered species survive,” Martinoff said. “It is an opportunity you don’t often get. I thought they looked fantastic.”
Game Specialist David Kuhn, who is based out of the Arizona Game and Fish Office in Yuma, said that once all the pronghorns had been processed, the ones that were chosen to be taken to the eastern edge of YPG were given a sedative so they could sleep during the trip. The others were released back into the semi-captive breeding pen.
Data from the tracking collars, he added, will be used to monitor the pronghorn’s location and to see how they are using the new landscape.
“When you are moving an animal from one area to another you want to keep an eye on them to see how they are doing,” Kuhn said. “If they are hanging out in a certain area it will also help us determine if we need to supplement their feeding or build a watch catchment there.”
Civilian employees from YPG, the U.S. Air Force, the U.S. Border Patrol, the U.S. Navy, and Marine Corps Air Station Yuma also took part in the December effort.
As a natural laboratory for testing virtually every piece of equipment in the Army’s ground combat, YPG also has a vested interest in responsible stewardship of the land and the wildlife that reside on it.
| Date Taken: | 01.08.2024 |
| Date Posted: | 01.08.2024 18:07 |
| Story ID: | 461336 |
| Location: | YUMA PROVING GROUND, ARIZONA, US |
| Web Views: | 214 |
| Downloads: | 0 |
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Yuma Proving Ground
