Once upon a time, bighorn sheep thrived. As recently as the 19^th century, the North American bighorn sheep population numbered over 1 ½ million. But today, only 40,000 remain. In California, the problem is even more pressing. In 1998, an estimated 335 Peninsular bighorn sheep remained in the US, in their range between the San Jacinto Mountains near Palm Springs southward to Baja California. This number represents a 71% population decline from 1979 levels. Peninsular bighorn sheep have been state listed as threatened since 1971, and were federally listed as endangered in 1998. Other bighorn subspecies, including the California bighorn in the Sierra Nevada, also perch on the brink of extinction.

In the 1800s, a combination of hunting, grazing, and livestock-borne disease severely impacted bighorn populations. Today, the biggest threat to the species is rapid urbanization. Urbanization results in habitat loss and fragmentation for the sheep. In some cases, this loss leads to changes in diet and behavior, which makes the animals more susceptible to parasites and disease, and leaves them vulnerable to predators such as mountain lions. Other related problems in the urban-mountain interface also contribute to bighorn deaths. In a study conducted by the Bighorn Institute in the northern Santa Rosa mountains between 1991 and 1996, numerous bighorn were killed when they were struck by cars, ingested poisonous ornamental plants, or strangled on wire fences. In this study, urbanization and its associated dangers accounted for 34% of the adult bighorn mortalities.

Since 1982, the Bighorn Institute has been fighting to save bighorn sheep. Created by a group of biologists and veterinarians, the Institute is dedicated to conservation of the world’s wild sheep population through research and education, with a particular emphasis on the Peninsular bighorn. The Institute resides adjacent to the city of Palm Desert, on 300 acres purchased from the Bureau of Land Management. In addition to educating the public about measures they can take to protect bighorn sheep, the Institute’s programs include:

• Captive Breeding and Wild Population Augmentation: Since 1985, a total of 77 Peninsular bighorn sheep born or rehabilitated at the Institute have been released into the Santa Rosa and San Jacinto Mountains. The released sheep provide valuable demographic and genetic support to wild populations.
• Santa Rosa and San Jacinto Mountains Bighorn Ecology: Radio-collared bighorn are monitored to document their habitat use, movements, nutritional levels, reproductive success, survival rates, and causes of death. This ecological information assists in judicious management of sheep.
• Peninsular Lamb Ecology: Since 1982, 90% of lambs in the northern Santa Rosa Mountains have died before reaching yearling age. In 1998, the Institute initiated a study of lambs to determine their habitat use, nutritional levels, disease exposure, survival rates, and causes of death. The data gathered will aid in recovery efforts.
• Lamb Rescue and Rehabilitation: Thirty-nine sick lambs have been captured in California’s Peninsular Ranges and brought to the Institute for treatment and study. The biological samples obtained from these lambs enables scientists to better understand disease processes in the bighorn, while allowing rehabilitated lambs to be re-released into the wild.
• Bighorn Disease Research: The Institute conducts medical screening on captured bighorn sheep to monitor disease exposure in the wild. In the late 1970s and 80s, several diseases severely impacted wild populations, although these illnesses were less prevalent in the 90s.
• Population Monitoring: Each fall, the Institute conducts a helicopter survey of the Santa Rosa and San Jacinto mountains to determine annual population estimates and lambing success of the bighorn sheep.
• Genetic Studies: In collaboration with the Center for Reproduction of Endangered Species at the San Diego Zoo, the Institute is investigating the genetic structure of the desert bighorn. Results of these studies will assist with the genetic management of both captive and wild herds.
• Biological Services: The Institute provides ecological information to various organizations and government departments to promote proper management and conservation of bighorn sheep. Institute researchers have assisted in ten western states, and the countries of Mexico, Mongolia, and Turkmenistan in their wild sheep preservation projects.

Future projects planned at the Institute include new office facilities, animal care units, and research laboratories. With the acquisition of sufficient funds, the Institute also hopes to construct a museum education center open to the public.

For further information, contact the Bighorn Institute at:
P.O. Box 262
Palm Desert, CA 92261-0262
Phone: (760) 346-7334
Fax: (760) 340-3987
E-mail: BI@BighornInstitute.org
Internet: Internet: www.bighorninstitute.org