Wild horses, also known as mustangs, roam across vast stretches of public land in Oregon, primarily in the state’s high-desert regions. These animals are descendants of horses lost or released by settlers and miners. The herds are protected by federal mandate, which recognizes them as living symbols of the historic spirit of the American West. Their existence creates a unique management challenge, requiring a balance between protecting the animals and preserving the delicate high-desert ecosystems they inhabit.
Defining Oregon’s Wild Horse Territory
Oregon’s wild horse population is largely confined to the arid, high-desert environment of the state’s eastern region. This territory consists of nearly three million acres designated as Herd Management Areas (HMAs), where the horses are legally allowed to roam. The largest concentration of these herds is found in the Bureau of Land Management’s (BLM) Burns District and Lakeview Resource Area.
Major HMAs define the specific geographic locations where these horses are managed. For example, the South Steens and Kiger HMAs are home to the famous Kiger mustangs, known for their dun factor coloration and Spanish ancestry. Other significant areas include Beatys Butte and Riddle Mountain. These territories represent federal lands where the horses compete for forage and water with other wildlife and permitted livestock.
Population Management and Oversight
The management of Oregon’s wild horses is governed by the Wild Free-Roaming Horses and Burros Act of 1971. This federal legislation declared these animals protected components of the public lands. The Act mandates that the managing agency, primarily the Bureau of Land Management, protect the animals while maintaining a thriving ecological balance on the rangelands. To achieve this, the BLM establishes an Appropriate Management Level (AML), which is the maximum number of horses that can be sustained without damaging the ecosystem.
The combined AML for Oregon’s HMAs is approximately 2,715 animals. However, wild horse populations have a high reproductive rate, often increasing by 15 to 20 percent annually, which makes maintaining the AML difficult. Recent estimates show the actual population has reached approximately 4,519 animals, exceeding the established AML by about 75 percent. This substantial overpopulation strains the fragile desert ecosystem, often leading to emergency management actions.
Gathering and Adoption Programs
When the wild horse population exceeds the Appropriate Management Level, the Bureau of Land Management conducts “gatherings” to remove excess animals from the range. These roundups are often performed using helicopters to herd the mustangs into temporary corrals safely and efficiently. Once gathered, the horses are transported to off-range holding facilities, such as the Oregon Wild Horse Corral Facility in Hines.
The primary goal for the removed horses is placement into private care through the federal adoption and sale programs. Potential adopters must submit a comprehensive application, including property and facility inspections, to demonstrate they can provide a humane and suitable environment for the animal. Upon approval, adopters pay a nominal fee, which was historically around $125 for an untrained wild horse or burro. Unadopted horses are then sent to long-term holding pastures where they live out their lives.
Fertility Control
In addition to removals, the BLM employs fertility control as a non-lethal population management strategy. They primarily use the Porcine Zona Pellucida (PZP) vaccine. PZP is an immunocontraceptive administered to mares, often by remote darting, to prevent pregnancy. This method is particularly effective in smaller, more accessible herds and requires an initial dose followed by an annual booster to maintain its efficacy. The use of fertility control helps to slow the population growth rate, aiming to reduce the frequency and scale of future helicopter gatherings.