Our Living; Resdiiires — Interior Wcsi 



.?.?.5 



of animals originally tVoiii ArizAina and Nevada 

 (Wolfe 1990: V. Graham. Colorado Division of 

 Wildlife, unpublished data). 



Nevada 



Desert bighorn {O.c. nelsoni) historically 

 occupied the central and southern portions of 

 Nevada (McQuivey 1978). Hunting the animals 

 was prohibited from 1901 to 1952. 

 Transplanting programs have been successful: 

 between 1968 and" 1988 more than 800 de.sert 

 bighorn were transplanted. From these animals. 

 21 transplanted herds have been established 

 (Delaney 1989). 



Buechner ( 1960) estimated the Nevada pop- 

 ulation at 1.500-2.000 in 1960. The state began 

 annual population trend counts in 1969. In 1993 

 the population was estimated at 5,294 animals, 

 occupying 45 mountain ranges (P. Cummings, 

 Nevada Division of Wildlife, unpublished data). 



New Mexico 



Although desert bighorns (O.c. me.xicaua) 

 historically occupied mountain ranges and 

 canyons in the southern part of New Mexico, by 

 1930 the animals were restricted to only four 

 mountain ranges, and by the late 1940"s were 

 found in only two (Weaver 1985). 



In 1972 the state constructed the 300-ha 

 (741 acres) Red Rock propagating enclosure 

 and added brood stock. Transplants from the 

 captive herd were subsequently made into the 

 Big Hatchet, Peloncillo. and Alamo Hueco 

 mountains (Sandoval 1979). 



The San Andres Mountain population was 

 formerly the state's largest, but declined from 

 200 to fewer than 25 by 1991 (Clark and Jessup 

 1992) because of psoroptic scabies [Psoroptes 

 spp.). 



Buechner estimated the New Mexican popu- 

 lation at 400-500 in 1960. In 1993 the estimat- 

 ed population was 295. of which 100 were at 

 Red Rock (A. Fisher. New Mexico Department 

 of Game and Fish, unpublished data). 



Texas 



Desert bighorn {O.c. mexicana) appear to 

 have occupied all the mountains in southwest 

 Texas west of the Pecos River (Carson 1941). In 

 1880 the population was estimated at 1.500 ani- 

 mals (Kilpatric 1982): some populations still 

 existed in the late 1930"s. By the mid-1950's all 

 bighorns had become extirpated except for a 

 small herd of 25: excessive hunting and compe- 

 tition with domestic livestock are believed to 

 have been major factors in the final decline 

 (Buechner 1960). 



In 1957 the Texas Game and Fish 

 Department began a highly successful captive 

 breeding and release program. By 1993 the 



free-ranging population was estimated at 310: 

 91 other sheep were in captivity (G. Calkins. 

 Texas Parks and Wildlife Department, unpub- 

 lished data). 



Utah 



Historically, desert bighoni {O.c. nclsoiii) 

 occupied canyons and ranges in southern and 

 eastern Utah. Significant population declines 

 occurred in the 1870"s (Buechner 1960). and the 

 state did not permit hunting of bighorn from 

 1899 to 1967. 



In 1967 limited hunting began, and in 1973 

 the state started an active transplant program. 

 Between 1973 and 1990. over 250 desert 

 bighorn sheep were transplanted, establishing at 

 least nine populations that augment four addi- 

 tional areas containing native populations 

 (Crestoetal. 1990). 



Buechner (1960) believed that only remnant 

 populations persisted in the state. Utah, which 

 has conducted aerial trend counts on bighorn 

 since 1969 (Cresto et al. 1990), documented 

 increasing populations statewide. Individual 

 populations, however, have exhibited large 

 increases and sudden declines. In 1993 the 

 desert bighom population was estimated at 

 2,200-2.250 (N. McKee and J. Kaipowitz, Utah 

 Division of Wildlife, unpublished data). 



Future of Desert Bighorn 



Since 1960 bighom have increased in num- 

 bers, but their population levels are still low 

 when compared with the estimates of pre- 

 European numbers and the amount of available 

 unoccupied habitat. The number of sheep in 

 individual populations has fluctuated greatly. 

 Population monitoring and efforts to restore 

 desert bighorn must continue to ensure viable 

 future populations. 



References 



Bleich. v.. J.D. Weyhausen, K.R- Jones, and R.A. Weaver. 



1990. Status of bighorn sheep in California. 1989 and 



translocations from 1971 through 1989. De.sert Bighom 



Council Transactions 34:24-26. 

 Buechner. H.K. 1960. The bighom sheep in the United 



States, its past, present and future. Wildlife Monograph 



4. 174 pp. 

 Carson. B. 1941. Man. the greatest enemy of desert bighom 



mountain sheep. Bull. 21, Texas Game. Fish and Oyster 



Commission. Austin. TX. 23 pp. 

 Clark. R.K.. and D.A. Jessup. 1992. The health of mountain 



sheep in the San Andres Mountains, New Mexico. Desert 



Bighom Council Transactions 36:30-35. 

 Cowan. I. McT 1940. Distribution and variation in the 



native sheep of North America. American Midland 



Naturalist 24:.S05-.S80. 

 Cresto, J., J. Karpowitz. and L. Seibert. 1990. Status of 



desert bighom sheep in Utah, 1989. Desert Bighom 



Council Transactions 34:31-32. 



