We assessed demographic and ecological patterns of endangered San Joaquin kit foxes (Vulpes macrotis mutica) relative to resource and competitor abundance in the Carrizo Plain National Monument (CPNM) during 2014 to 2019. Based on prey sign surveys, abundance of kangaroo rats and rabbits increased from 2014 to 2019. Kangaroo rats increased in kit fox diets while the rabbits and rodents increased in coyote diets. Visitation rates by both kit foxes and coyotes increased during the study, and the proportion of individual stations that were visited by both species also increased. We used GPS collars to examine kit fox survival, reproduction, and space use in a year of low prey availability (2015-16) and a year of high prey availability (2017-18). Kit fox survival was 0.69 in 2015-16 and 0.87 in 2017-18. Reproductive success was 44.4% in 2015-16 and 72.7% in 2017-18. Mean home range size was 4.3 km2 in 2015-16 and 1.3 km2 in 2017-18. On the CPNM, kit fox population dynamics and ecology appear to be primarily influenced by kangaroo rat abundance and not by competition from coyotes. Consequently, kit fox populations appear to be regulated by “bottom up” processes.