Bobcat–coyote niche relationships during a period of coyote population increase

Abstract

Resource partitioning between bobcats (Felis rufus) and coyotes (Canis latrans) was investigated in eastern Maine during 1979–1984, when colonizing populations of coyotes were rapidly expanding. A total of 2615 radio locations of 10 resident bobcats and 6 resident coyotes were used to investigate activity patterns, spatial relationships, and habitat use. The daily distribution of activity by both species was similar during all seasons, and neighboring bobcat–coyote home ranges overlapped. Simultaneous locations of eight sympatric bobcat–coyote pairs (≥ 10% home range overlap) indicated an apparent lack of attraction or avoidance between neighboring heterospecifics. Bobcats preferred hardwood stands during all seasons (P < 0.05), and occupied softwood-dominated stands less than expected (P < 0.05) during autumn and winter. Coyote habitat use was less consistent, and indices of habitat-use overlap with bobcats varied from 0.60 during autumn to 1.00 during winter. Seasonal indices of diet diversity, based on the examination of 1495 feces, indicated that bobcats were more specialized than coyotes. Coyotes became omnivorous during summer and autumn, while bobcats remained strict carnivores during all seasons. Indices of diet overlap were higher during winter (0.76) and spring (0.72) than during summer (0.49) and autumn (0.49). The numbers of bobcats and coyotes trapped in eastern Maine during 1977–1986 were negatively correlated (r = −0.75, P < 0.02), suggesting a population response to exploitation competition between these two carnivores.