Science and Research

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Using Sound Science to Inform Management of Wild Horses and Burros 

The Bureau of Land Management (BLM) uses the latest science in its efforts to ensure that viable numbers of wild horses and burros can thrive on healthy public rangelands. For example, the BLM uses science to monitor rangeland vegetation, soils, water, wildlife habitat, and the effects of wildfire. Additionally, the BLM is implementing science and research recommendations from the National Academy of Sciences’ June 2013 report to the BLM:

  • The BLM initiated new research projects in 2015 to develop new and more effective tools for controlling wild horse and burro population growth. Learn more about those efforts here.
  • To more accurately estimate wild horse and burro populations, the BLM implemented better population survey methods in 2014. Each year, one-third of all Herd Management Areas will be surveyed using methods developed by the U.S. Geological Survey (USGS).
  • In addition to the aerial surveys using USGS methods, the BLM is researching other ways to accurately estimate population size (see Spotlight on Research below).
  • Research began in 2014 to evaluate the effectiveness of new formulations of SpayVac, a Porcine Zona Pellucida (PZP)-based contraceptive vaccine. 
  • To better understand public preferences for the management of wild horses and burros, the BLM is conducting a socio-economic research project that will include focus groups and a national survey.


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Spotlight on Research!

USGS volunteers posed on back of vehicle with research supplies. The Wild Horse and Burro Program has engaged the U.S. Geological Survey (USGS) to conduct a study to determine if genetic material (DNA) within feces could be used to accurately estimate horse populations, while also providing information about genetic diversity and consumption of invasive species. USGS is conducting this research in collaboration with Colorado State University.

Population estimation from fecal DNA is an established technique that can produce accurate results with just one sampling session and requires no disturbance or handling of the animals. The study, which took place at Little Book Cliffs Wild Horse Herd Management Area in Colorado, used samples taken from a wild horse herd with a known population size, which allows researchers to assess the accuracy of population estimates from the fecal samples. USGS volunteers collected the samples over 10-day periods in 2014 (May, August and October) to determine differences in DNA quality by season. Volunteers were trained in sterile collection methods, and surveyed for dung in accessible field areas within the herd management area during each sampling period. Over 600 fecal samples were collected on each sampling trip, providing a plethora of data. Genetic samples are currently being analysed at the USGS Molecular Ecology Lab in Fort Collins, Colorado. Results are expected in late 2015.

Pictured: USGS volunteers holding the final samples out of more than 1,800 collected for a study at BLM’s Little Book Cliffs Wild Horse Herd Management Area in Colorado. The study focuses on using genetic material (fecal samples) to estimate horse population size and determine herd genetics in a non-invasive manner.