inoc. 1 53.2: Sh3/Cali UNIVERSITY OF AT URBANA-CHAMPAIQIM BOOKSTA( IKS Digitized by the Internet Archive in 2013 http://archive.org/details/annericandesertbiOOunit Desert Bighorn Sheep Desert bighorn sheep symbolize the rugged spirit of the American West. Living in rocky desert canyons, they, peccary, and deer are the only native, hoofed animals now surviving in the harshest areas of our southwestern deserts. However, poor habitat condi- tions, lack of water, and human disturbance have caused desert bighorn sheep populations to drop from several hundred thousand to less than 16,000 over the last 150 years. Bighorn sheep, named by early pioneers, are best known for the rams' huge horns. The horns grow in a tight circle and can weigh up to 30 pounds. They are not shed each year like antlers; in fact, a ram's age can be determined by the growth rings on his horns. The ewes' horns are smaller, more slender, and more spiked than the rams'. They curve back slightly and only grow to about 12 inches. The hooves of the bighorns have two toes sepa- rated by a soft central pad, which enables them to grasp jagged rocks. These special hooves permit them to scramble and zigzag over steep, craggy cliffs in the rocky areas where few other large animals can live. In addition, their springy bodies are well suited to leaping up or dropping down a nearly vertical rock, or barely pushing off narrow outcroppings of "bald" desert mountains with little vegetation. Desert bighorns are smaller than their mountain cousins — the rams typically weigh about 160 pounds, and the ewes, 105 pounds. They have a thin, buff-gray coat which is similar in texture to that of a deer or elk. This coat helps to regulate their body temperature during the cold nights and hot days on the desert. Keen vision enables the bighorns to protect themselves from predators — they can see up to 5 miles away! With their amber-yellow eyes on the sides of their heads, bighorns can see behind themselves. Their acute senses of hearing and smell also warn them of attacks from predators, such as mountain lions and coyotes. Life Cycle — Mating season usually occurs in late summer. Older rams will occasionally hold head- butting contests to win the right to mate with ewes. With about 10 yards separating them, their ears back and heads lowered, they run forward, lunging and smashing their horns together in a violent crash that echoes up to a mile away. Their strong horns, skulls, and necks act as a shock absorber against the impact. The crash may stun the animals, but with a shake of their heads the rams are ready to back up and repeat the charge. The rams grunt, snort, and kick each other with their front legs. These contests may last for hours, until one ram backs off, drops from exhaustion, or is knocked out cold. ^OGITC.^Y uKiv:i;:c:-y OF illino;'.. '■-^T l.isr , 'AMPAIGN ^ U.S. Department of the Interior ^ Bureau of Land Management The ewes mature and begin mating at about age 3. Most ewes bear only one lamb a year, but some occasionally have twins. Lambs are bom in late winter on high, narrow slopes, safe from predators and adjacent to water and vegetation. Ewes will only tend to their own young — an orphaned lamb is left to die. The lambs can walk after only a few hours and can run and jump within days. As they get older, lambs play games like "foUow-the-leader" and "king of the mountain." They also fight and challenge each other in competitions of strength and agility. Ewes typically travel in bands with their new lambs and 1- and 2-year-old offspring. At about age 3, young rams leave these groups to travel alone or in small bands. Older rams leave their mates after the lambs are bom, travel in bachelor bands during the spring and early summer, and then rejoin ewes in time for the next mating season. Survival — Desert bighorn sheep generally stay in the same area for their entire lives, which rarely exceed 10 years. They live where their ancestors lived and retum annually to the same location for mating and giving birth. Herds may number more than a hundred animals, but most are smaller. The sheep eat a variety of grasses, shmbs, and other plants containing moisture during the winter season. During hot, dry, desert days, the bighoms rely on good water supplies and get supplemental moisture from water-holding plants like cacti. Having no upper front teeth, they must hold and mash vegetation between their lower front teeth and the homy pad of their upper front jaws, jerking their heads to break off vegetation. Competition for forage between bighoms and livestock, loss of water supplies, and disease have all been factors contributing to the decrease in population of desert bighoms since the 1800s. More recently. encroachment by humans upon bighorn habitat has become a growing problem. Poorly designed wire fences can also result in injury to bighoms, and poaching continues to be a problem in some areas. Bighorns Need Help Eighty percent of desert bighorn habitat — nearly 9 million acres — is in six western states on public land managed by the Bureau of Land Management (BLM). For the last two decades, BLM has worked with State agencies and private groups to develop water sources, improve vegetation conditions, and protect habitat areas from human disturbance. The key to preserving this American treasure is to improve its habitat. Additional actions undertaken by bighorn enthusiasts, BLM, and State wildlife manage- ment agencies include reintroducing bighorn sheep into ranges they previously inhabited. Because the desert bighorn is more likely to survive when surface water is available, the promotion of suitable water supplies is a primary effort of BLM and its volunteers. The constmction of artificial water catchments, such as guzzlers, ensures storage of winter runoff, which is then available during critical summer months. Managing vegetation around waterholes is also important. Water-hungry shrubs are discouraged in order to increase the flow and access of water. In addition to ensuring adequate water, these critical areas must be protected from human encroachment to allow bighoms to use available water sources without fear. Other BLM efforts to improve bighorn habitat include: management of livestock grazing, building safe fences, regulating excessive recreation near sensitive habitat, and managing populations of competing animals. 5h 2,/Ca\^. CALIFORNIA ^^ sf — ^ I I BLM Lands Category I — Viable Herds pniF '■- j Category II — Remnant or Reintroduced Herds In 1989, BLM published its "Rangewide Plan for Managing Habitat of Desert Bighorn Sheep on Public Lands." The goal of the plan is to recover populations of desert bighorn in six states — Arizona, California, Colorado, Nevada, New Mexico, and Utah. Each state will develop a more specific plan to establish local objectives within the scope of the Rangewide Plan. BLM biologists and managers in California have been working with the California Department of Fish and Game, private individuals, and conservation groups to enhance bighorn sheep habitat for over 20 years. Population surveys of bighorn now put California's total at more than 4,700 sheep, an increase of over 1,000 animals over the past 15 years. Habitat management plans are being developed for most of the 63 individual herds of bighom that reside in California. These plans detail the specific needs of each herd, such as water development sites and neces- sary road closures. Major habitat management plans completed by BLM specialists over the past 4 years include McCain Valley/In-Ko-Pah Mountains, Oro- copia, Clark Range, New York Mountains, Sheep Hole Mountains, and Argus Range. California has carried out an active program of habitat enhancement, primarily in the form of water development projects. For example, the development of 45 big game guzzlers in the California Desert District has substantially increased the species' useable range. Many of these guzzlers have been funded by BLM and installed in cooperation with the California Department of Fish and Game and volunteer groups. These developments, coupled with burro reductions, have led to major increases in sheep numbers. Over the past 4 years, six bighom relocations have been performed as cooperative ventures by BLM, the California Department of Fish and Game, and the Society for the Conservation of Bighom Sheep. In 1986, 44 bighorns (25 from the Kelso Peak/Old Dad Mountains and 19 from the Marble Mountains) were released in the Sheep Hole Mountains to augment an existing population of approximately five sheep. Aerial counts and ground counts now indicate a reproducing population of 25 animals in the release area. There have also been three bighom transplants into the Whipple Mountains, where bighorns had been absent since the 1950's. The transplants were accomplished after burro removals and water source installations were implemented. The minimum estimated population of bighorns in the Whipples is now approximately 135 animals. Another successful tool for habitat recovery in Califomia is the challenge cost share program. Since 1985, Congress has provided "cost share" funding for desert bighom projects, whereby the Federal govem- ment matches gifts of money, material, and labor donated by private individuals and organizations. The bighorn program remains focused on opening potential habitat for full use by these magnificent desert animals. Additionally, there is a continuing and growing need to maintain those water developments and other habitat improvements already constructed. Increased public involvement and support are needed and welcome. To find out what you can do, contact any of the agencies or groups listed below. Bureau of Land Management Califomia State Office Federal Building 2800 Cottage Way, E-2841, CA-932 Sacramento, CA 95825-1889 Phone 916-978-4725 California Department of Fish and Game 1416 9th Street Sacramento, CA 95825 Phone 916-445-3531 Society for the Conservation of Bighom Sheep 3113 MesaloaLane Pasadena, CA 91107 Phone 818-794-7680 Foundation for North American Wild Sheep 720 Allen Avenue Cody, Wyoming 82414 Phone 307-527-6261 Copies of the Rangewide Plan are available from your local BLM office. * U.S. GOVERNMENT PRINTING OFFICE: 1990— 77« mm m .,Jmi