| Sierra Nevada red fox (Vulpes vulpes necator; SNRF) is distinguished from other subspecies by its tight association with the upper life zones of major mountain ranges in Oregon and California. One hypothesis to explain its narrow bioclimatic niche is that the characteristically deep winter snow of the subalpine zone provides a refuge, preventing establishment of breeding territories by competitively dominant coyotes. If so, climate-mediated upslope range shifts of coyotes potentially threaten persistence of SNRF populations, a danger accelerated in recent years by massive drought. During the past four years of this drought period, we collected coyote fecal DNA on a 25 km stretch of the Sierra Nevada crest encompassing the known distribution of the Sierra Nevada Distinct Population Segment of SNRF. We used microsatellites to determine the individual identity, sex, and inter-relatedness associated with each scat sample. These data were then used to determine spatial distribution and reproductive success of resident individuals, relative abundance of transient individuals, and population abundance in the vicinity of known red fox occurrences. Our results establish a baseline for coyote residence in low-snow years and provide a novel opportunity for future comparison in high-snow years. |