Identifying individual mountain lions Felis concolor by their tracks: refinement of an innovative technique

This study refines a method reported by Smallwood and Fitzhugh (Smallwood, K.S., Fitzhugh, E.L., 1993. A rigorous technique for identifying individual mountain lions Felis concolor by their tracks. Biological Conservation 65, 51–59) that attempted to discriminate between individual mountain lions by certain measurements of their tracks in the field. During the months of January–March 1996, we followed 10 radio-collared mountain lions in the Sierra Nevada of California and obtained photographs of their tracks in the soil and snow under many different environmental conditions. Linear and area measurements were determined from track photographs and Fisher’s discriminant analysis was used to differentiate between each track set. Unlike the Smallwood and Fitzhugh analysis, we were certain about the identity of most of the mountain lions that made tracks. Our results indicate that track sets had both correct and incorrect “groupings” and that these groupings were sensitive to the type of substrate in which a track set was found, the time of day it was photographed, and the number of tracks in a set. In general, it is important to minimize variation associated with substrate and time of day between track sets and to concentrate on sets that contain three or more tracks. This technique has potential application in wildlife conservation; however, the cautionary guidelines, developed in this paper, should be considered.