BLM’s McCullough Peaks decision to benefit herd, rangeland health

The Bureau of Land Management Cody Field Office’s action plan concerning population management of the McCullough Peaks Wild Horse Herd Management Area (HMA) is currently underway, with fertility control darting ongoing in the field and bait trap gathers scheduled to begin in mid-November.
The decision, outlined in an environmental assessment released Sept. 20, approved measures to reestablish the Appropriate Management Level (AML) for the McCullough Peaks herd through bait trap gathers, selective removals and fertility control.
The AML for the McCullough Peaks HMA—the population range determined to ensure the ecological health of the herd and rangelands—is 70 to 140 wild horses, not counting foals.
Sarah Beckwith, public affairs specialist for the BLM Wind River/Bighorn Basin District, said the AML was established in the McCullough Peaks HMA in 1985 and confirmed during the 2015 resource management planning process, which included various public input periods.
“We established the appropriate management level by evaluating and analyzing rangeland resources and population data over a several year period, including data relating to vegetation and soil types, weather and water quality,” she said.
The herd numbered 140 in 2015, but Beckwith said other horse gather priorities across the west and a lack of available national funding put the BLM’s management plans on hold.
The current population stands at 181 horses based on direct counts in 2023.
The goal of the proposed action in the BLM’s environmental assessment is “to achieve and maintain a wild horse population within the AML for the McCullough Peaks HMA through the removal and population control measures.”
Proposed Action
After opening its environmental assessment for a month-long comment period, the BLM Cody Field Office’s final plan outlined its proposed action and addressed suggestions and concerns raised by the public.
Proposed action will focus on bait trap gathers, retaining older horses and utilizing the population growth suppression treatments Porcine Zona Pellucida (PZP) and GonaCon.
Due to public concerns about the bait gather of older horses, the Cody Field Office “will not remove the older population of horses living within the McCullough Peaks HMA.” Staff familiar with the horses will help ensure family bands remain together and that horses slated for removal are safely trapped.
Abel Guevara, wildlife biologist and wild horse specialist for the BLM Cody Field Office, said, “We will look at horses that are five years old and younger, and then determine which horses to remove.”
Guevara added the agency hasn’t yet determined which horses will be removed.
“Horses that are selected to be removed from the range will be sent to one of our off-range corrals to be processed i.e. freeze brands, vaccinations, etc., and will be offered for adoption,” he said.
In the meantime, the BLM is at work administrating fertility control treatments via field darting. Beckwith credited PZP, which the agency has administered since 2011, for slowing the herd’s population growth to an average of 2% annually.
“As opposed to untreated herds which can double every four years,” she said.
Not all mares respond to PZP, so the proposed action would implement the additional treatment of GonaCon on mares age 13 and older that have already contributed to the genetic diversity of the herd. According to the assessment, GonaCon-Equine is one of the most preferable methods available for contraception in wild horses and burros and is approved by authorized federal, state, tribal, public and private personnel (EPA 2013, 2015).
Additionally, mares can regain fertility if GonaCon-Equine ceases to be administered.
Necessary Action
Though the Cody Field Office received public comments that expressed frustration with its decision, the agency determined that action was necessary because the number of wild horses above the AML can affect the herd and land’s overall health.
Not taking action is not an option, according to the assessment. The BLM will only have to remove more horses in the future if nothing’s done now.
The proposed action is also a matter of federal and state regulations. The BLM protects and manages wild horses and burros as required by congress under the authority of the Wild Free-Roaming Horses and Burros Act (WFRHBA) of 1971, as amended. The agency is also responsible for “preventing unnecessary or undue degradation of public lands” and maintaining a multiple-use relationship.
“The BLM’s overarching mission promotes multiple-use on public lands,” Beckwith said. “The public lands that lie within the McCullough Peaks HMA can and do support multiple uses including recreation, wildlife and wild horse habitat, grazing and many other uses.”
The BLM responded to additional public suggestions in its assessment such as the elimination of grazing, raising the AML to accommodate the horses and avoid gathers, and allowing horses to die of natural predation.
Friends of a Legacy (FOAL), a nonprofit committed to protecting and preserving the wild horses of the McCullough Peaks, was one such group that submitted concerns to the assessment.
“One of the concerns we had was making sure we understood the goals of the gather, what the final intent was, and that’s been clarified and addressed,” said executive director Heather Green. “I think they’re trying very hard to move forward with integrity and with the best interests of the herd at heart.”
Green said FOAL has always approached its mission by working cooperatively with the BLM. Though the nonprofit expressed hesitation about the bait gather, “we’ve accepted that it’s necessary to maintain a healthy ecological balance.”
FOAL hopes to participate in the bait gather “from an observational standpoint…so that the gather can be approached thoughtfully with the herd in mind.”
“We do care a lot and we intend to keep advocating and make sure the area is managed in such a way that the horses continue to thrive,” Green said.
The BLM Cody Field Office’s environmental assessment and other associated documents are available to view at the BLM National NEPA Register.