Carson City District-Stillwater Field Office

Pilot Mountain HMA Facts

Where is the Pilot Mountain herd and what is special about these animals?

The Pilot Mountain Wild Horse Herd roams over about 255,040 acres of public and private land acres in the Pilot Mountain Herd Management Area (HMA), located near Hawthorne, Mineral County, Nevada.

Current horse population estimates are approximately 302 horses within the HMA, with 104 horses residing outside the HMA. The 104 horses residing outside of the HMA often congregate along U.S. Highway 95 near Walker Lake, creating a serious public safety hazard. In February-March 2010, at least seven wild horses were killed in vehicle accidents. Fortunately, there have been no known human injuries in these and other similar accidents along this highway.

The area is also utilized by livestock (under terms and conditions outlined in grazing permits) and a variety of wildlife, including bighorn sheep, pronghorn antelope and mule deer.

The Pilot Mountain wild horses are most likely descendants of local ranch horses that were found in 1971 in what is now the HMA.

Why is the gather necessary?

Reducing population size and treating mares with PZP would ensure that the remaining wild horses are healthy and vigorous and in balance with other range resources. Treating 76 mares will slow reproduction, helping to maintain a healthy Pilot Mountain herd and to restore or maintain the rangelands in a healthy condition, maintaining the Appropriate Management Level (AML), and reduce the number of excess wild horses that would need to be removed in the future.

Damage results from over utilization of resources when populations exceed the carrying capacity of the rangeland. Reducing wild horse populations to within established AMLs will make significant progress in attaining the management objectives indentified in the Carson City Consolidated Resource Management Plan (CRMP) and the Standards for Rangeland Health & Guidelines for Grazing Management (S&Gs) in the Sierra Front Northwestern Great Basin Area.

The 104 horses (outside of HMA) along U.S. highway 95 near Hawthorne/Walker Lake, Nevada, are a public safety hazard as vehicle collisions are potentially fatal to humans. If the 104 wild horses were captured and released back into the HMA they will simply return to their home range adjacent to the highway.

What needs to be done to maintain this herd?

To maintain a healthy Pilot Mountain herd and to restore or maintain the rangelands in a healthy condition, the BLM plans to gather enough excess horses to restore the population to a level that can be sustained in balance with the other uses described above.

The BLM has determined the appropriate management level (AML) to be between 249-415 horses within the Pilot Mountain HMA.

Under the 1971 Wild Free Roaming Horses and Burros Act, BLM is required to "remove excess animals" to "restore a thriving ecological balance to the range."

Approximately 242 horses within the HMA will be gathered with 53 excess horses being removed, and the remaining 189 horses, which include 76 mares to be treated with Porcine Zona Pellucida (PZP), a two year fertility control vaccine, would be released back into the HMA to achieve ecological balance.

Post-gather, every effort will be made to return the released horses to the same general area from which they were gathered. The BLM intends to return to these HMAs in 2-3 years, if necessary, to gather and retreat the mares to maintain the proposed population control measures.

BLM plans to gather and remove 104 excess horses residing well outside the HMA.

The animals removed will be offered for adoption through the BLM’s wild horse and burro adoption program, or placed in long-term holding pastures.

The current estimated Pilot Mountain wild horse population of approximately 406 animals is 157 horses over the lower limit of 249 horses set for the AML.

How does BLM determine the Appropriate Management Level (AML) for horses?

The AMLs were established upon completion of an in-depth analysis of habitat suitability, resource monitoring and population inventory data.

The upper limit of the AML range is the maximum number of wild horses that can be maintained within an HMA while maintaining a thriving natural ecological balance and multiple use relationship on the public lands.

Establishing the AMLs within a population range allows for the periodic removal of excess animals (to the low end) and subsequent population growth (to the maximum level) between removals.

Development of the Herd Management Area Plans (HMAP) for Pilot Mountain included public involvement.

Which livestock grazing allotments overlay with this wild horse HMA?

Three livestock grazing allotments, Pilot/Table Mountain, Cedar Mountain and Gillis Mountain, spread across the HMA. The wild horses primarily use the Pilot/Table Mountain Allotment portion of the HMA due to limited water supplies in other areas.

Forage is allocated by Animal Unit Months (AUMs). An AUM is the amount of forage consumed in a month by an adult horse, a mare and foal, two burros, an adult cow or cow and calf, or five sheep.

BLM actively manages authorized livestock use to mitigate impacts, while wild horses roam freely, year-round as the law allows. During rangeland health evaluations conducted in 2009, wild horse sign was commonly evident and abundant in the HMA, while signs of use by cattle were negligible.