BLM Wild Horse Population Survey in Nevada and Oregon



BLM Office:

Oregon/Washington State Office

Media Contact:

Jeff Clark

BLM and the U.S. Fish and Wildlife Service (USFWS) have joined forces to conduct a joint aerial population inventory of wild horses on nearly four million acres of land located in northwest Nevada and southeast Oregon. The survey will be conducted beginning June 20 and will last up to eight days, using a fixed-wing aircraft. The goal of the cooperative interagency project is to improve wild horse population counts, utilizing improved population survey methodology, in an area known for significant movement of horse herds. “Past population surveys and management projects by BLM and the USFWS within the survey area have shown that the animals may move throughout the Hart Mountain and Sheldon National Wildlife Refuges managed by the USFWS and several herd management areas managed by BLM," said BLM Nevada State Director Ron Wenker. “This joint effort will produce a base line count and distribution for the entire area as a whole. We are planning to return in the fall for a second survey, where we will see how and where the herds moved, and how that affects population counts within the individual areas." The flight will encompass herd management areas (HMAs) administered by the BLM Winnemucca District in Nevada; the BLM Lakeview and Burns District Offices in Oregon; the BLM Cedarville District Office in California that manages some of the HMAs within Nevada, and the two wildlife refuges managed by USFWS. The U.S. Geological Survey (USGS), that conducted research into improving BLM's population counts, will assist with the population survey by modeling and analyzing the data collected on the flight and providing a population estimate with a 95 percent confidence interval. This improved survey methodology, called Simultaneous Double-Count with Sightability Bias Correction, uses two observers to independently observe and record data on groups of individual horses. The methodology incorporates peer-reviewed techniques that have been used for decades to estimate wildlife populations around the world. BLM specialists in Wyoming and Nevada have assisted USGS researchers since 2004 in developing and improving the inventory protocols. Accurate wildlife population surveys are challenging, as they are very strongly dependent on skill of the individual observer, species surveyed and group size. They are also affected by ruggedness of the terrain and vegetation cover. Additional information about BLM's wild horse and burro program is available online at:

The BLM manages more than 245 million acres of public land located primarily in 12 western states, including Alaska, on behalf of the American people. The BLM also administers 700 million acres of sub-surface mineral estate throughout the nation. Our mission is to sustain the health, diversity, and productivity of America’s public lands for the use and enjoyment of present and future generations.