The free-roaming equine herd around Arizona’s Salt River has weighed on conversations about how much impact the land can sustain.
Picture yourself drifting along the Salt River northeast of Mesa, Arizona — the towering flat-sided mountains seemingly from another world and the soothing sound of the water offering a much-needed respite from the chaos of everyday life. Rounding the final bend, you see the awe-inspiring sight of the free-roaming horses, with all their untamed beauty. Few things seem more magnificent than witnessing these horses in this kind of habitat.
Yet despite feeling natural in this setting, there are questions about whether the land they’re on has evolved to be capable of supporting them.
These horses descend from ones brought to North America by the early Spanish explorers in the 16th and 17th centuries, according to the Salt River Wild Horse Management Group. One notable missionary, Father Eusebio Kino, brought and left hundreds of Spanish horses and cattle in what is now the state of Arizona in 1687.
After centuries of integration into the landscape, many believe that free-roaming equine herds have found their spot in the circle of life in the Sonoran Desert and other areas across the American West. However, not all herds, including the one at Salt River, have been on the land for more than a few decades, and opponents argue that these animals are not native enough and have no natural predators, which makes them ripe for overpopulation.
Without a background in rangeland management, this might not raise alarms. However, according to research, their presence is problematic; the abundance of feral horses traversing the riverbank can negatively impact the area’s native plants, animals, and landscape. A study done in 2018 by the University of Arizona, looking at what the Salt River horses eat, had found there was little to no perennial grass at their sampling locations — a shocking observation as the Sonoran Desert grows many varieties of perennial grass.
Others counter that horses are actually beneficial to the environment but lack the scientific research to back up that claim.
In addition to the landscape, there are concerns about the well-being and health of the horses. The University of Arizona study noted a “high dependence on woody vegetation in the diet, especially in years of average to slightly above average precipitation and production as measured in 2017, suggests that the current system likely lacks the capacity to meet the long-term nutritional requirements of the herd at the given density.”
The debate about wild horses and similar free-roaming herds in the western half of the U.S. has long been fueled by disagreement over land use, often charged with emotion stemming from the almost mythological status these animals have achieved. They represent a part of the history of the West that is no longer visible to many in today’s culture and community. They symbolize freedom, adventure, and hard work. Often, horses are seen as companion animals and can help people connect with their emotions and feelings.
This makes the simple presence of the horses more personal than for other wildlife.
A study out of Colorado State University was conducted to better understand the roots of this conflict among different stakeholder groups: the Bureau of Land Management, BLM permittees, and wild horse advocates. Study author Elena Graciela Dosamantes found these groups all shared common values about wild horses: “Cultural values attributed to wild horses and attitudes towards management methods did not differ substantially among the three stakeholder groups observed. Rather, the main difference appeared in the suite of cultural values and their relative strengths held by each group.”
And all must operate within the same decades-long legal framework.
In 1971, Congress passed the Wild and Free-Roaming Horses and Burros Act for “all unbranded and unclaimed horses and burros on public lands in the United States.” This landmark piece of legislation occurred at a time when herds were rapidly declining, and concerned citizens stepped in with political activism. The act made harassment or killing these animals on federal land a crime and established a framework for their protection and management.
At the same time, the BLM was tasked with creating a plan to balance the landscape’s ecology with the feral horses and other land users, including livestock and wildlife.
Oversight of wild horses is a contentious topic in the U.S., with the BLM estimating, as of March 1, 2024, that 73,520 horses and burros are in 177 herd management areas across 10 western states. This spans an area of nearly 28 million acres and doesn’t even include all free-roaming herds, like the one at Salt River. The BLM reported that 5,335 wild horses and burros were removed from the landscape last year with 8,045 placed into private care (adoptions, sales, transfers), 720 were given fertility control treatments, and the total expenditures were $157.8 million.
Yet according to the study from the UofA, “The Salt River horses are not currently classified as Wild under the Wild Free-Roaming Horses and Burros Act of 1971 because the herd was not present in the area upon enactment and as a result are not afforded protected status under the existing Federal statute.” The horses did gain some protection in 2016 with the signing of Arizona HB2340, which limits the removal of the horses and other management options from the Tonto National Forest as feral or stray livestock.
On July 31, 2015, the U.S. Forest Service, a federal agency responsible for managing national forests and grasslands, posted an impound and removal notice for the horses, stating they would either be removed or otherwise “disposed of.”
The Salt River Wild Horse Management Group, a nonprofit group committed to protecting the Salt River horses from harm, raised the alarm about this notice and — in conjunction with state legislators, the media, and lawyers — fueled unprecedented public outrage. This prompted the U.S. Forest Service to commit to a 120-day temporary delay of the gathering. Shortly after, the USFS ultimately rescinded the order.
The following year, then-Arizona Gov. Doug Ducey signed a bill that stated the horses were not stray livestock and made harassment of the horses illegal. This bill also formed the current relationship between the management group and state and federal officials.
Ducey was highly supportive of the bill, yet allegations arose that the measure had less to do with science and more to do with his wife’s sympathy and long-time philanthropy involving the free-roaming herd.
The Salt River Wild Horse Management Group began short-term management of the herd in 2018 in collaboration with the U.S. Forest Service and the Arizona Department of Agriculture. Their efforts in controlling and managing a non-native species in areas with no natural predators and high public sentiment continue to raise concerns. Still, their team of volunteers and concerned citizens continue to work toward what they see as a productive future for the horses.
According to the group’s website, their goal is “freedom, protection and humane management of this treasured historic and recreational resource.” It claims to have a daily presence in the Tonto National Forest and have done so for many years.
The group did not acquiesce to repeated requests to be interviewed for this article.
Concerns from some corners have lasted for years, with action being taken recently. Beginning in 2023, the Center for Biological Diversity, an activist group that often clashes with farmers and ranchers in the area, began filing lawsuits related to the Salt River area. And in the summer 2024, it sued the U.S. Forest Service over the size of the herd. This case has since been dismissed with prejudice, eliminating any possibility of refiling.
According to reporting by Arizona-based ABC15, Robin Silver, the co-founder of the Center for Biological Diversity, brought forth the lawsuit with the belief that, “The Forest Service is not protecting the land and the native wildlife species that depend on it.”
The center said it would like to see the herd reduced to 50 animals, down from a current count of about 300 that roam 20,000 to 30,000 acres in Tonto National Forest. The group claims that the horses consume the forage needed for endangered wild birds such as the neotropical songbirds, yellow-billed cuckoos, southwestern willow flycatchers, and the Yuma clapper rail.
In granting the dismissal, the federal judge in the case referenced an Endangered Species Act analysis stating that the land-management plan “is likely to result in net beneficial effects to federally listed species.”
The Salt River Wild Horse Management Group has argued that no scientific studies are referenced and that they believe the horses benefit the landscape and wildlife population.
CEO Simone Netherlands of the wild horse management group told ABC15, “They don’t put one single scientific study behind that. They can’t put any scientific evidence behind that, so it’s basically just their narrative. We believe the exact opposite. We believe that wild horses have a positive impact on their environment.”
While the Center for Biological Diversity makes it clear that it puts feral horses in the same category as livestock, there are marked differences between the grazing management of feral horses and livestock. It is a long-standing management practice to estimate forage production on rangelands. Forage production is the weight of forage produced within a certain period of time on a given piece of land. This estimation allows for accurate and acceptable stocking rates of livestock and wildlife carrying capacity.
Carrying capacity is only an estimate and can be complex, but these numbers are typically set well below the maximum utilization rate to allow for seasonal regeneration of grazed areas and to limit degradation of the area. Ranchers who lease federal and state land are expected to adhere to these numbers and must be willing and able to move animals if rainfall is lower, resulting in poor rangeland conditions.
Since 2019, the Salt River Wild Horse Management Group has controlled the herd’s population through porcine zona pelucida — an immuno-contraception delivered through a dart administered in the field. The group claims this is the “only acceptable form of birth control for wild horses, as it does not harm nor influence their hormones and therefore does not harm or influence their reproductive behaviors and herd dynamics. Any other form of birth control, such as geldings or overyectomies, are cruel, expensive, and will influence their hormones, which is why we do not support those forms of birth control for wild horses.”
This method of population control is effective for only one to two years after darted, and a booster must be administered to remain effective. To see a clear herd response and reduction, the time needed to execute this management plan is close to 10 years. According to the BLM website, “Studies indicate that 75 percent or more of the mares in a herd must be treated to have a significant effect on herd growth.”
Other population control methods are in place in other herds, with the most significant impact being removing animals from the range. Ideally, these animals are adopted, but those deemed unfit remain in long-term holding facilities, accounting for 60 percent of the BLM’s budget. The American Association of Equine Practitioners and the American Veterinary Medical Association support the ongoing development and use of long-lasting, effective contraceptives.
In addition, the groups say they support the use of permanent sterilization methods, such as spaying or castration, in selected herds where repeated capture or darting with contraceptive vaccines is not feasible.
Overpopulation of feral horses is a problem far outside Salt River herd in central Arizona. According to the AVMA, “The number of wild horses and burros on public lands is three times greater than the appropriate management level determined by the BLM. The BLM-designated level is approximately 27,000; the national estimated on-range population as of February 27, 2019, is approximately 88,000.”
The latest data from the BLM show that numbers have been reduced to 73,520 in 2024, but it still far exceeds the designated appropriate number of animals. It’s also estimated that an additional 50,000 horses are maintained off-range in long-term holding facilities.
As the debate surrounding the Salt River wild horses continues, it is evident that managing wild horse populations in the American West is a complex issue. Ongoing legal and legislative efforts underscore the importance of finding sustainable solutions that consider both the heritage of these animals and the conservation of the natural environment.
Tiffany Selchow lives on a working cattle ranch in the Superstition Mountains of Arizona. With a life entrenched in the Western lifestyle and agriculture, her goal is to share worthwhile, intriguing, and exciting stories of the rodeo world, ranchers and farmers, the outdoor lifestyle, and more.
