ADAPTING TO CHANGES IN RESOURCE AVAILABILITY BY AN ADULT MALE MOUNTAIN LION

John F Randolph; Institute for Wildlife Studies; randolph@iws.org; David K. Garcelon

Mountain lions (Puma concolor) are a solitary, ambush predator found across California. Deer are their primary prey, although they prey upon a variety of other species. On the Modoc Plateau in northeastern California, mule deer (Odocoileus hemionus) were the primary prey species accounting for 71% of the diet for our 27 collared mountain lions. One exception was an adult male (M166), who predominantly fed on feral horses (Equus caballus). Of 54 kill site investigations that were ungulate prey, all were feral horses. This male’s home range resides almost exclusively on the Modoc National Forest, and in 2016 the Forest Service began feral horse removal in an effort to manage the population. From 10 September to 4 October 2020, 506 horses were removed from M166’s home range. One month after the removal, this lion shifted his range and for the first time was detected preying on mule deer. In mid-December 2020, M166 returned to his original home range and resumed his equine diet. This change in spatial use may correlate to a change in resource availability due to the feral horse removal; however, alternative explanations may include shifting home range to find more mates.

Poster Session  InPerson Presentation