Last month, 10 female and four male Sierra Nevada bighorn became the first new herd of its kind to be reintroduced in California in 25 years.
These animals were once found throughout alpine areas of the Sierra Nevada, however by the 1970s the bighorn had almost disappeared due to disease spread by contact with domestic sheep and goats, as well as unregulated commercial hunting. The animals were placed on the endangered species list in 2000.
The bighorn’s new home is at the southern end of the Sierras in Inyo County. The animals were selected from a larger herd as part of a program to increase their range. The California Department of Fish and Wildlife began the project to reestablish herds in 2007 in an attempt to rebuild the population. The new area meets the requirements for bighorn populations with rugged, steep mountain slopes between 5,000 feet and 14,000 feet high.
The reintroduction program aims to disperse the animals across a wide range to give them the best chance to flourish.
"When you recover an endangered species you want to restore as much of the historic range as you can," Tom Stephenson, a fish and wildlife bighorn recovery program leader, told the Los Angeles Times. "You don't want small isolated populations prone to catastrophe. So our recovery goals are both numeric and geographic."
Luckily, the animals’ historic range was largely preserved within five national forests and five national parks.
Officials captured the animals from the two largest wild herds in the Sierra Nevada and transported them by truck to the release site. Once there, the animals were blindfolded to keep them calm and given a medical exam and a radio collar. Then, the crates were opened and the animals were released.
Ten herds of Sierra bighorn now wander the mountains and the state has plans to create three more to increase numbers from about 100 to 500 animals.
Sierra Nevada bighorn are genetically distinct from other species of bighorn sheep, with rams that grow flared, curling horns. These herbivores summer in alpine regions and move down to lower elevations in the fall.