Habitat use of red foxes in Yellowstone National Park based on snow tracking and telemetry

Based on radiotelemetry and snow tracking in 2003 and 2004, we examined habitat selection by red foxes (Vulpes vulpes) in Yellowstone National Park at the 3rd-order (within-home-range selection) and 2nd-order (selection of a home range) scales. We analyzed habitat use using a euclidean distance method that compares distances from each location to each habitat type against expected distances. Overall, red foxes used forested habitats more than open habitats. Red foxes were closer to Douglas-fir (Pseudotsuga menziesii) habitat than expected at both scales, suggesting greater use. Open, mesic grassland at the 2nd-order scale also was used less than expected. Red foxes were farther from ecotones than expected at both scales, a result primarily due to heavy use of Douglas-fir forest. in which they were farther from ecotones than expected, whereas being closer to ecotones than expected in all other habitat types. At the 2nd-order scale, home ranges of red foxes contained more mesic and sagebrush (Artemisia) habitats in winter compared to summer. We hypothesize that competition with coyotes (Canis latrans) greatly impacts habitat use by red foxes. For example, when using coyote-favored habitats with less cover, such as sagebrush and mesic grasslands, red foxes may remain closer to ecotones and thus closer to escape cover. Additionally, their superior mobility in deep snow compared to coyotes may allow red foxes to include more mesic and sagebrush habitats within their home ranges in winter, and thus exploit the greater food resources that have been found to occur in these habitats. Snow tracking and radiotracking revealed similar patterns of habitat use, but snow tracking generated fewer samples because it is labor intensive, only possible after snow events, and not possible outside of winter. However, snow tracking did reveal aspects of red fox behavior that telemetry could not, such as where red foxes foraged. Red foxes in this study may be the native subspecies V A. macroura, which may partially explain selection for forested habitats and against low-elevation, mesic Grasslands.