Sierra Nevada Bighorn Sheep Recovery Program - Predator Monitoring and Management

mountain lion in tree
Adult mountain lion

two mountain lion kittens
Mountain lion kittens in den

bobcat at night with deer carcass
Bobcat on deer kill

mountain lion track in sand
Mountain lion track

Predator monitoring and management is an integral part of the Sierra Nevada Bighorn Sheep Recovery Program. For Sierra bighorn recovery, the primary focus of predator monitoring and management is mountain lions, but program personnel investigate Sierra bighorn mortalities from all causes and collect data on bobcat and coyote sign in addition to mountain lions. Mountain lions kill bighorn sheep, but may have little or no impact on population trend if predation is infrequent. Some mountain lions learn to specialize on bighorn sheep. Consequently, in some of the small isolated populations of Sierra bighorn that now exist, predation can have a major impact on the growth rate of the population. For this reason, mountain lions are removed if they are considered a significant threat to the recovery of an Sierra bighorn herd unit. The goals, with respect to predators, are to monitor predation risks to Sierra bighorn, provide Sierra bighorn herd units enough protection to ensure recovery, and collect information on the behavioral interactions of Sierra bighorn, deer, and predators to gain a complete understanding of the dynamics in this important ecological community.

Mountain Lion Monitoring

Mountain lions were intensively monitored on the winter range of the largest Sierra bighorn population unit, Wheeler Ridge, starting in 1991. In 2000, the effort was expanded to include all of the winter ranges of Sierra bighorn. The effort continued until 2011. Over 130 mountain lions were fitted with radio collars in the eastern Sierra Nevada during this time period. In, collaboration with USDA Wildlife Services, the Sierra bighorn Recovery Program included two predator control specialists who tracked mountain lions daily and used their specially trained hounds to capture them. New advances in technology allowed more intensive monitoring via GPS collars that provide much more accurate data at a much higher frequency than the traditional VHF collars. GPS collars were used to identify clusters of locations that indicate kill sites. Sites can be investigated to determine the prey species. These collars allowed the Sierra bighorn program personnel to identify individual mountain lions that posed a threat, quantify predation rates, and determine whether predation limits recovery of Sierra bighorn. Removing lions that are a legitimate threat to the recovery of Sierra bighorn units is the most efficient and effective protection for Sierra bighorn and promotes recovery of an endangered species and the restoration of an ecosystem. From 2011 to 2016, lion monitoring was accomplished solely through the survival of collared bighorn sheep. In 2016, as a part of a statewide lion monitoring and population estimation project, more intensive monitoring has been resumed. Additional GPS collars are being deployed to more directly monitor mountain lion activities in bighorn sheep habitat.

About Mountain Lions

Mountain lions go by a number of names and this causes some confusion. The names cougar, puma, panther, and catamount, all refer to the same animal. The scientific name (Puma concolor) reflects the solid tawny color of the mountain lion along its upper body. The belly is white and there are black markings at the base of the whiskers, the back of the ears and the tip of the tail.

The young are born with spots that fade by six months of age. Mountain lions are sexually dimorphic meaning that there is a physical difference between males and females. Adult females in the Recovery Program area average 40 kg. while adult males average 58 kg. Despite this, it can be extremely difficult to tell a male and female apart unless the animals are in hand.

General sign of coyotes and bobcats are noted by predator monitoring personnel on a daily basis. This data collection includes sightings, kills and tracks found while monitoring and tracking mountain lions. Predator monitoring personnel investigate reported mountain lion sightings by the public. Bobcats are very often mistaken for mountain lions, sometimes because people are unaware that there is another cat species besides mountain lions in the area, because they thought bobcats have no tail at all, or because humans can not judge distance well and a bobcat can easily appear the size of a mountain lion if the distance is less than the observer perceives it to be. Bobcats in our Recovery Program area rarely exceed 16 kg., generally have numerous markings about the body, especially on the legs, and have a shortened but distinguishable tail.

Dogs, coyotes, and house cats are also frequently reported as mountain lions. Dog tracks are very often reported as mountain lion tracks. Cat tracks have distinguishing features in the heel pad. The base of the heel pad will have three cleats and the top will be flat. These characteristics occur in the tracks of every member of the cat family. Very rarely a dog may also have a similar track in which case the presence of claw marks, a pointed tip in the heel pad and other factors may eliminate it as a possible cat track. Size is not useful in distinguishing mountain lion tracks from dog tracks. Black mountain lions are infrequently reported but in the history of mountain lion hunting, which includes hundreds of thousands of specimens, dating back for over a century in both North and South America, a black mountain lion has never been definitively observed. The black panthers seen in movies are either black jaguars or black leopards, both species which can commonly produce melanistic offspring.