Evidence of Mammalian Carnivores at the Desert Tortoise Research Natural Area, Western Mojave Desert, USA, between 1989 and 2012.

During a multi-year demographic study of Agassiz’s desert tortoise (Gopherus agassizii) at the Desert Tortoise Research Natural Area (Natural Area), in the western Mojave Desert, USA, we recorded evidence of evidence of mesocarnivores that commonly prey on desert tortoises on a 7.77 square-kilometer study area. The study area included land inside and outside the fenced boundary of the Natural Area. We recorded locations, condition and recency of sign, and type of sign present at burrows, dens, and den complexes used by desert kit foxes (Vulpes macrotis), coyotes (Canis latrans), American badgers (Taxidea taxus), and bobcats (Lynx rufus). We also recorded scat piles by species using them, amount, and relative ages of the scats. Scats were checked for evidence of desert tortoise remains. Observations of live mesocarnivores were noted also. We compared differences in predator pressure inside and outside the boundary fence of the Natural Area and whether mesocarnivores were a driver for changes in tortoise demography.