The term “wild horse” in the American West context refers to a population of free-roaming animals that are technically considered feral, as they are descendants of once-domesticated horses brought by European explorers. These animals, often called mustangs, are not native wildlife but are protected under the Wild and Free-Roaming Horses and Burros Act of 1971, which recognizes them as “living symbols of the historic and pioneer spirit of the West.” Nevada hosts the largest population of these protected animals on public lands. Management of horse numbers must be balanced with the health of the ecosystem and the interests of various land users.
Current Population Estimates and Management Targets
The Bureau of Land Management (BLM) is the federal agency tasked with managing these herds. As of the most recent estimates from March 1, 2025, the BLM tallied approximately 30,732 wild horses roaming on the public lands within Nevada. This figure represents the largest state population and underscores the scale of the management challenge in the region.
This current estimated population is compared against a threshold known as the Appropriate Management Level (AML), which the BLM defines as the number of animals that can exist in balance with other resources and uses of the rangeland. The combined AML for both wild horses and burros across Nevada’s Herd Management Areas is set at 12,811 animals. The present on-range population of wild horses alone, which exceeds 30,000, is far above this established maximum number.
The disparity between the current count and the AML is substantial, indicating an overpopulation of more than 17,900 horses and burros in Nevada alone. Unmanaged wild horse populations can increase rapidly, with herd sizes capable of doubling in approximately four to five years due to a lack of natural predators. This exponential growth rate is the primary driver behind the BLM’s ongoing efforts to reduce herd sizes to protect the fragile desert ecosystems from degradation.
Where Nevada’s Wild Horses Roam
Management of the wild horse population is the responsibility of the Bureau of Land Management, which oversees the vast majority of the public land where the animals reside. In Nevada, the BLM manages 83 distinct Herd Management Areas (HMAs), which encompass approximately 15.6 million acres of federal land designated for the protection and management of wild horses and burros.
The terrain within these management areas is characteristic of the high desert and arid Great Basin, consisting of sparse vegetation and limited water resources. This environment is particularly susceptible to damage from overgrazing and trampling, which intensifies the urgency of population control. The concentration of the largest wild horse population in this delicate ecosystem makes Nevada a focal point for land use debates. The BLM’s mandate is to maintain a natural ecological balance on these public lands while also preserving the wild horse herds.
Methods Used for Population Control
Because the on-range population significantly exceeds the Appropriate Management Level, the BLM employs several physical actions to reduce herd numbers, primarily “gathers” or “roundups.” These operations are typically conducted using helicopters to herd the animals into temporary corrals on the ground. The goal of a gather is to remove excess animals from the range to prevent overgrazing and resource depletion.
Once captured, the removed horses are transported to off-range facilities for processing, where a veterinarian checks their health, and they are vaccinated and branded. The ultimate fate of these animals is either adoption or sale to qualified individuals through programs that often offer financial incentives. Horses not adopted or sold are sent to long-term holding facilities, which are essentially large leased pastures, or short-term corrals where they receive lifetime care at the taxpayer’s expense.
In addition to removal, the BLM utilizes non-lethal methods to slow the rate of population growth, primarily through the use of fertility control vaccines. The most common immunocontraceptive is PZP (Porcine Zona Pellucida), which is administered to mares to prevent pregnancy for a period of one to four years. Fertility control is considered a humane way to manage herd growth and is most effective when applied consistently to herds that are already near their target AML. However, applying the vaccine, often via darting, is difficult in remote areas, necessitating the capture and release of animals for treatment.
The Ongoing Debate Over Horse Management
The management of Nevada’s wild horses remains controversial, fueled by the conflicting interests of various stakeholder groups. Conservation groups and wild horse advocates often oppose the large-scale gathers, arguing that the removals are traumatic and that the Appropriate Management Levels are set artificially low to favor other land uses, particularly livestock grazing. They advocate for greater reliance on reversible fertility control vaccines as a sustainable approach to population stabilization.
Conversely, ranchers and some land managers express concern that the excess horse population directly competes with livestock for scarce forage and water, accelerating the degradation of already fragile rangelands. They point to the environmental impact of overpopulation, which can lead to the destruction of vegetation and soil health. The rapid increase in herd numbers beyond the land’s capacity creates an ecological imbalance that necessitates intervention.
The financial aspect of the program also generates debate among taxpayers and policymakers. The majority of the BLM’s Wild Horse and Burro Program budget is consumed by the costs associated with caring for unadopted animals in off-range holding facilities. Housing, feeding, and providing medical care for tens of thousands of captured animals nationwide costs over $100 million annually. This expenditure reduces funding available for on-range management strategies, such as widespread fertility control, perpetuating a cycle of expensive removals and housing.