Habitat selection by American mink during Summer is related to hotspots of crayfish prey

Abstract

Habitat selection by mammalian carnivores may be driven by prey availability, physical characteristics of the habitat, and landscape context. However, the cues used by carnivores to select habitat are often unclear. We examined the seasonal diet of American mink Neovison vison and determined if the abundance of a primary prey, crayfish, was an important driver of habitat use during summer in an agricultural landscape in Illinois. We also evaluated effects of stream size, water depth, riparian buffer width, and urbanization on occupancy of stream segments by mink. We collected mink scats during three seasons and tested for seasonal differences in the percentage of occurrence and volume percentage of prey classes in the diet of mink. Crayfish remains were the dominant component of mink scats during summer. In summer 2012, we performed occupancy surveys for mink and concurrently measured crayfish densities and habitat features in 59 stream segments. Site occupancy by mink was related positively to presence of local areas with high crayfish concentrations (hotspots) instead of local habitat characteristics that might indicate high prey densities. Mink also were associated negatively with degree of urbanization and stream size. Our study highlights the effectiveness of integrating data on diets and occupancy modeling to obtain insights on cues used by carnivores to select habitat.