Mountain Lions in Northeastern California

In late 2015 we initiated a study to examine the movements and food habits of mountain lions in northeastern California.  As part of our ongoing study of the ecology of pronghorn in that region of California, we discovered that a high percentage of the mortality of adult pronghorn was caused by predation by mountain lions.  Because pronghorn usually occupy open sagebrush steppe habitat, biologists were surprised to learn that an ambush hunter like mountain lions could successfully prey upon pronghorn.

Mountain lion in sunlight

It is thought that the changing vegetation structure on the Modoc Plateau (Modoc and Lassen Counties) may be contributing to the increased ability of mountain lions to prey upon pronghorn.  Woodland habitat, made up primarily by encroaching juniper forest, has decreased the more open habitat historically characteristic of the plateau, and perhaps provided greater opportunities for mountain lions to get close enough to pronghorn to make successful attacks.

Mountain lion close with 2 juveniles eatingMountain lion capture workup Mountain lion capture teeth Trail cam photos by Wildlife Health Center Southern California Cougar Project                   Capture photos by IWS
Further, mountain lions have never been studied in the northeastern part of the state and little is known of their habits in that region.  As part of this investigation, we will be trapping lions and placing GPS satellite collars on them to get detailed data on their movements.  We will use these data to locate sites where there are likely to have made kills of prey species, and then we will investigate these kill sites to determine the species, sex and age of the prey species.  We will also use locations of the sites to examine how mountain lions may be using the interface between the encroaching juniper woodland and the sagebrush habitat.

This investigation is being done in cooperation with the UC Davis Wildlife Health Center and the California Department of Fish and Wildlife.
Background photo by Mulmatsherm - CC license, cropped