Live Trapping and Monitoring Mountain Lion Movements within a Feral Horse Population in Storey County, Nevada, 2005 - 2007

Abstract

Author(s): Gray, Meeghan; Spencer, Jack, Jr.; Thain, David | Abstract: The depredation of feral horses by mountain lions is usually a rare phenomenon and only a few cases have been documented in scientific literature. While such reports indicate that mountain lions are easily capable of killing feral horses, these studies have focused solely on the feral horses and have neglected to consider the mountain lion’s perspective (i.e., movement patterns, prey choice). Today, feral horses have created an artificial prey base for mountain lions, and even if natural ungulate species were not present, mountain lions appear to survive and flourish while consuming feral horses. During a feral horse behavior study conducted in 2005, a resident mountain lion in the Virginia Mountain Range was deemed responsible for several feral horse deaths, with most of the carcasses found being young foals or juvenile horses. A large live trap was developed and was strategically placed in a mountain lion travel corridor where the depredated horse carcasses were found. Bait in the live trap was changed on a weekly basis to prevent spoilage. The trap was set from October through December 2006 and monitored each morning. A 7-yearold, 60-kg female lion was caught in the trap after 3 months of trapping efforts. It was tranquilized, weighed and measured, and fitted with a satellite GPS collar. The satellite collar gave 4 locations per night. Based on the those GPS locations, we determined the lion had depredated on many feral horses, and it continued to range in the same area, even though other native wildlife species, such as mule deer, were in low densities. We monitored her progress until October 2007 to determine overall movement patterns and prey choice.