Pronghorn Project Update – Part 4

By John Ehlers

There have been several positive steps toward transplanting Pronghorns to the Chuckwalla Bench area of southern California. First Jim Atkinson (USF&W) who chairs the Sonoran Pronghorn Recovery Team, included the Chuckwalla Bench transplant in the update of the Sonoran Pronghorn Recovery Plan. We are part of the official documented plan.

We met with Jim Hervert (Arizona Game & Fish), Leon Lesicka (Desert Wildlife Unlimited), Gerry Mulcahy (California Fish & Wildlife) officials from BLM and the Marine Corps at the California F & W office in Blythe on August 7th. This was a kickoff meeting to get the primary players together to discuss the recovery program and travel out to the Chuckwalla Bench to let everyone look over the area. Unfortunately there had been a heavy rain two days previous so we were unable to get off the Bradshaw Trail and onto the Chocolate Mountain Aerial Gunnery Range for fear of encountering unexploded ordnance uncovered by the rain.

Despite this, everyone was able to get an adequate look at the landscape, water sources, and plant species. The highlight of the trip was the realization that a section of state owned land (640 acres) lay right where we could use it for a 10-20 acre holding pen. The pen is needed to contain the transplanted animals for a few weeks to allow them to recover and acclimate after the capture and transplantation. The animals are sedated before and during transport in a specialized trailer designed for transporting game animals.

On October 15th John Ehlers and Kevin Clark of the San Diego Natural History Museum represented San Diego SCI at the fall Sonoran Pronghorn Recovery Team Meeting in Ajo, Arizona. The team consists of employees from the various federal and state agencies directly involved in the recovery effort. These are the people who are actually doing the day to day work at the breeding pens and free range area that has increased the number of Sonoran Pronghorns in Arizona from under 20 in 2002 to over 200 today. The “team” is talented, motivated and dedicated and their hard work is directly responsible for the opportunity to bring the Sonoran Pronghorn back to southern California. I can’t say enough about the “team” and the level of cooperation that has been achieved between the various agencies involved.

Kevin Clark and I joined Leon Lesicka and John Hervert on October 17th to inspect the section of state land and surrounding area. The state land is ideal for the holding pen and the required water source within the pen. Leon had previously shown the Marine Corps biologist the sites picked out for additional water sources on the gunnery range. These water sources have been in the planning cycle for some time and along with existing sources will support the pronghorns when they are released and spread out over the surrounding area.

We met again October 30th at the Blythe office of California F & W. It was concluded that we would move forward with the detailed planning for the holding pen and water source on the section of state land. This is not only a good site but using state land simplifies the paperwork required. We will locate the four corners of the section and determine the exact location of the pen and water source.

Once the pens and water are located and designed we will produce a detailed list of the materials needed. The pen is basically a 10-20 acre 6 foot high hogwire enclosure. The hogwire is covered by 4’ high shade cloth to prevent the pronghorns’ hooves from being caught in the wire. The enclosure is surrounded by an electric wire to discourage predators and to protect the pronghorns. We expect to be able to pick up much of the materials needed from surplus material stockpiles but there will be many “opportunities” to invest fundraising proceeds. Leon Lesicka stated that DWU has the tank and drinker box and will supply both as well as some T posts.

Jim Atkinson said that we can expect a transplant of approximately 20 animals per year starting in 2016. All of the agencies involved are stepping up to make this happen.

Some additional information that some of you may wonder about is:

Ajo, Arizona is about 50 miles south of Gila Bend and the headquarters of the Cabeza Prietta National Wildlife Refuge is located there. The breeding enclosure is located about 15 miles west of Ajo. The free ranging animals are located on the NWR, the Berry Goldwater Range (shared by the Air Force and Marine Corps), the Organ Pipe National Monument and some other nearby areas.

There is a second group that was established two years ago on the Kofa NWR about 80 miles north of Yuma. This transplant has been very successful and our animals will most likely come from this herd which roams the refuge and Yuma Proving Grounds.

The Chuckwalla Bench is about a third of the way between Palo Verde and the Salton Sea. The Bradshaw Trail runs through it and is the main access road.

As previously reported, SDSCI supported attempts to recover DNA from the hides of animals taken in the early 1900’s. Out of seven hide samples submitted, DNA was recovered successfully from only one hide. This hide was taken near Parker, Arizona. The DNA showed that animal to be a mixture of Sonoran and Americanus. This means that the Sonoran antelope ranged further north than previously thought. The University of Arizona is currently analyzing a bone sample from an antelope taken in the 1930’s near the south end of Laguna Salada (south of Calexico). While the genetics are interesting, it has been concluded that the antelope last seen on the Chuckwalla Bench in 1942 were likely Sonoran and we’re moving forward with that conclusion. The pronghorns survived for a long time in that location but didn’t survive the nearly one million troops and tanks that trained there under General Patton. I’m guessing that antelope tasted a lot better than K rations.