Proceedings of the fifth mountain lion workshop: 27

92 PROCEEDINGS OF THE FIFTH MOUNTAIN LION WORKSHOP
IN THE PENINSULAR RANGES OF CALIFORNIA
Esther Rubin. Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of
California, Davis, CA 95616, USA
Walter Boyce. Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of
California, Davis, CA 95616, USA
Charles Hayes. Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of
California, Davis, CA 95616, USA
Steve Torres. California Department of Fish and Game, 1416 Ninth Street, Sacramento, CA 95814, USA.
Mark Jorgensen. Anza Borrego Desert State Park, 200 Palm Canyon Drive, Borrego Springs, CA 92004, USA.
An investigation of cause-specific mortality among 91 radio collared bighorn sheep was conducted from November
1992 through January 1996 in the Peninsular Ranges of southern California. Mountain lion predation was the most
significant cause of mortality and accounted for 63% (27/43) of all mortalities in the 6 sheep populations included in the
study. Lions accounted for 0-100% of all mortalities within these populations, and 0-27% of the radio collared sheep within
any given population were killed by lions annually. The age at capture of the sheep varied significantly among populations,
and the age distribution of sheep killed by lions did not appear to differ from this pattern. Sheep of both sexes were preyed
upon by lions but a statistical comparison between sexes was not possible because only a small number of rams were radio
collared. Predation occurred during all times of the year except for the months of June, July, and August. Sixty-seven
percent (18/27) of the predation events occurred between December and March. It appears that lion predation has been a
significant limiting factor during the past three years, and sustained high levels of predation by lions may adversely affect the
long-term viability of this threatened metapopulation of bighorn sheep.
ORIENTATION, MOVEMENTS, AND SURVIVAL OF TRANSLOCATED
COUGARS IN NEW MEXICO
T.K. Ruth. Hornocker Wildlife Institute, Moscow, ID 83843, USA.
K.A. Logan. Hornocker Wildlife Institute, Moscow, ID 83843, USA.
L.L. Sweanor. Hornocker Wildlife Institute, Moscow, ID 83843, USA.
M.G. Hornocker. Hornocker Wildlife Institute, Moscow, ID 83843, USA.
L.J. Temple. New Mexico Department of Game and Fish, 87714, USA.
We conducted a 2-year study of wild-caught translocated cougars to evaluate translocation as a management tool to:
1) re-establish cougar populations in historic ranges, 2) relieve the threat of inbreeding in isolated populations, and 3)
manage nuisance cougars. Our objectives were to document orientation, movements, establishment, and survival of
translocated cougars and to make comparisons with similar parameters for cougars in a reference population. Thirteen
cougars were translocated an average of 477 km from the San Andres Mountains (SAM) study area in south-central New
Mexico to 9 release sites in northeastern New Mexico and were monitored from 9 December 1990 through 7 January 1993.
A fourteenth cougar was translocated 338 km from the SAM to northwestern New Mexico on 8 April 1989 and monitored to
29 May 1990. Initial orientation of cougars away from release sites ranged from 22E-313E and were uniformly distributed
about a 360E circle. Eight (4 M:4 F) of 14 cougars had endpoints > 80 km from their release sites and endpoint directions
that were almost exclusively south, southwest or southeast (x=181E), suggesting the cougars homed toward the source
population. Two males returned to their original home ranges in the SAM. Distances moved from release sites to endpoints
ranged from 3-285 km for 8 females and 11-494 km for 6 males. Nine of 14 translocated cougars died during the study.
Annual survival rates for translocated cougars averaged 0.55 for females and 0.44 for males and were lower for both sexes
during the second year of the study. Translocation was most successful with cougars that were 12-27 months of age. For
management or conservation programs, we suggest that 12-27 month-old cougars are the best candidates for translocation.