Wild Horses and Burros

Data from these studies help inform management decisions regarding ungulates on public lands, typically in large, jurisdictionally complex landscapes. Recent work involves investigations on the effects of herd size and movements of elk, bison, and wild horses on various ecosystem components. Specifically, scientific efforts include quantifying interactions among herbivores, plants, and soils...

Molecular tagging is a new application of molecular genetic techniques to traditional mark-recapture methodology designed to address situations where traditional methods fail. In such studies, non-invasively collected samples (such as feces, feathers, or fur) are used as a source of DNA that is then genotyped at multiple loci such that each individual animal can be uniquely identified. Thus, each...

The Wild Free-Roaming Horses and Burros Act of 1971, as amended, states that, "It is the policy of Congress that wild free-roaming horses and burros shall be protected from capture, branding, harassment, or death; and to accomplish this they are to be considered in the area where presently found, as an integral part of the natural system of the public lands (PL 92-195, Sec. 1331, Congressional...

Because population estimates drive nearly all management decisions pertaining to wild horses and burros, accuracy is important. Several widely used techniques exist for conducting aerial population estimates of wildlife, but individually, each has important limitations. Researchers at the U.S. Geological Survey, Fort Collins Science Center (FORT), are evaluating combinations of these techniques...

Wild horse populations often increase at high rates on U.S. western rangelands, which in turn can lead to habitat degradation. The U.S. Geological Survey and the Bureau of Land Management are cooperating on studies investigating the potential of fertility control drugs to reduce foaling rates. In addition, because nearly every management issue concerning wild horses depends on accurate herd counts...

FORT scientists are leading collaborative research projects to provide the BLM with better tools for managing expanding wild horse and burro populations. We are assessing the carrying capacity of wild horse habitats, behavioral effects of spaying mares and gelding a proportion of a herd’s stallions, testing the efficacy of an intrauterine device for mares, and evaluating four fertility-control...

The wild horses that roam the west are feral descendents of domestic animals that either escaped from or were intentionally released by early European explorers and later settlers. As a result of both origin and contemporary management, the Spanish or Iberian influence remains strong in some wild horse populations (e.g., the Kiger, Pryor Mountain, and Sulfur Mountain herds). In other populations...

Molecular tagging is a new application of molecular genetic techniques to traditional mark-recapture methodology designed to address situations where traditional methods fail. In such studies, non-invasively collected samples (such as feces, feathers, or fur) are used as a source of DNA that is then genotyped at multiple loci such that each individual animal can be uniquely identified. Thus, each...