Desert bighorn sheep are some of the most intriguing mammals of canyon country. They are wary of human contact, and blend so well into the terrain they inhabit, that sightings are a special event. Once feared of becoming extinct, the desert bighorn are making a tentative comeback in southeast Utah due to a comprehensive reintroduction effort by the National Park Service. With one of the few remaining native herds, Canyonlands has been a vital source of animals for restoration efforts.
Desert or Nelson’s bighorn sheep (ovis canadensis nelsoni) are considered by most biologists to be a unique subspecies. Desert bighorns have adapted to hot, dry climates, unlike their Rocky Mountain cousins, and have longer legs, lighter coats and smaller bodies. Bighorn sheep are common in ancestral Puebloan and Fremont pictographs, an indication of their presence and prominence in indigenous cultures. Accounts from European explorers in the late 1600s estimate that more than two million desert bighorn once roamed the southwest.
By the late 1800s however, bighorn sheep had disappeared or declined in many areas. Extremely vulnerable to diseases from European livestock, herd after herd of wild sheep were decimated by pathogens like scabies (an ear mite) and anthrax (a bacterial disease) introduced by domestic sheep. Bighorns were also killed by early explorers, settlers and trophy hunters. Increased competition with domesticated cattle and sheep for food didn’t help the situation. In 1975, Utah’s population numbered around 1,000 sheep.
When Canyonlands was established in 1964, there were approximately 100 bighorn sheep remaining in the park. To protect these animals, grazing allotments within the park were phased out during the 1970s. The Bureau of Land Management, whose lands border the park, limited grazing leases to cattle only, which lessened the risk of exposure to disease from domestic sheep – probably the most important step in preserving bighorn populations.
In the early 1980s, biologists began relocating bighorns from the growing population in Canyonlands in order to establish new herds. Since sheep are poor dispersers, this is the only way to return them to their historic ranges. To accomplish this, sheep are captured in nets fired from helicopters, their health and age assessed, and suitable animals are transported by ground to a relocation area.
Since the program began, sheep have been reestablished in Arches National Park, Capitol Reef National Park and Glen Canyon National Recreation Area. Sheep relocated to the San Rafael Swell west of Canyonlands have created two herds totaling more than 600 animals. Today, the bighorn population in Utah is estimated at 3,000 animals. There are roughly 350 sheep in Canyonlands, with separate herds in each of the districts. Though disease still takes its toll, the park’s population has done well in recent years.
Increased human activity and development continue to threaten the desert bighorn sheep. For the remaining herds to survive, intensive management and conservation measures may be necessary. The protection of undeveloped land and wilderness areas is key to the species’ survival, and Canyonlands will continue to play a large role in this effort.