Wild horse and burro herd size relatively unchanged since last year

The population of wild horses and burros roaming public lands managed by the Bureau of Land Management remained relatively static over the last year, according to the latest annual survey results released by the agency today.

Find: wild horse and burro management data

The BLM estimates there were approximately 82,883 wild horses and burros on BLM public lands as of March 1, 2023, which is still about three times what is sustainable and healthy for the land and the herds. The 2023 estimate is 499 more than what was estimated in 2022 and follows two years of population decline from a peak of more than 95,000 animals in 2020. The estimated population is compiled based on the results of commonly used wildlife survey methods and could be as low as 71,494 or as high as 96,083 animals given the uncertainty levels associated with aerial surveys.

Managing wild horse and burro population growth on public lands is important because wild horses and burros have no predators that can naturally control herd growth in most areas. Absent management, herds increase rapidly – doubling in size every 4-5 years. Over a short period of time, wild horse and burro herds can grow large enough to overgraze their habitat and degrade important water sources, which can lead to starvation and thirst for the animals and disrupt other wildlife.

The BLM has taken important steps in recent years to bring herds back to sustainable levels. Since 2018, the BLM has gathered and removed more than 64,000 wild horses and burros from overpopulated herds, which is more than triple what was accomplished in the previous five years. Safely gathering and removing animals is the only way to make meaningful reductions in herd size in the near-term. Removed animals are offered for adoption to qualified homes, or eventually transferred to a contracted pasture for lifetime care.

The BLM has also significantly increased the use of fertility control  vaccines to slow and stabilize herd growth. Available vaccines can safely prevent pregnancy in a wild horse mare for 2-5 years, and are most effective when animals can be located, identified, and re-treated over multiple years. In Fiscal Year 2022, the BLM treated more animals than it has ever treated in one year, and the agency plans to continue focusing on implementing more fertility control in herds that are near sustainable levels. The agency also supports on-going research to develop better, longer-lasting vaccines.

Thanks to support from Congress, the BLM has made significant progress towards our goal of managing healthy wild horses and burros on healthy public lands and look forward to working with Congress, our partners, and other interested parties to continue on this trajectory. Prior to 2021, wild horse and burro herds had increased for eight consecutive years.

The BLM manages and protects wild horses and burros on nearly 27 million acres of public lands across the Western United States. The Wild Free-Roaming Horses and Burros Act directs the BLM (and the U.S. Forest Service) to manage wild horse and burro populations “so as to achieve and maintain a thriving natural ecological balance.” To achieve and maintain this balance, the BLM is focused on gathering excess animals from overpopulated herds and finding good private care for them through adoptions and sales, while at the same time expanding fertility control treatments to slow herd growth. Animals not placed into private care are provided space and grassland to roam on BLM-contracted pastures. 

Read: the top 5 things you should know about the Wild Horse and Burro Program

The BLM compiles annual wild horse and burro population estimates based on data collected by field specialists using scientifically validated aerial survey techniques developed by U.S. Geological Survey scientists. Statistical analysis of the data leads to an estimated total number of animals, including those that may be missed during the survey. The BLM normally surveys about one third of all herds using this methodology each fiscal year. For herds not surveyed in a given year, the BLM typically assumes 20 percent growth for horses and 15 percent growth for burros.