INTERACTIONS BETWEEN COYOTES AND RED FOXES IN YELLOWSTONE-NATIONAL-PARK, WYOMING

Interactions between coyotes (Canis latrans) and red foxes (Vulpes vul pes) indicate that coyotes often tolerate foxes, and yet at other time s, are aggressive and kill foxes. The frequency and context in which c oyotes are aggressive or tolerant of foxes are unknown. We observed 66 interactions between coyotes and red foxes in Yellowstone National Pa rk, Wyoming, from February 1991 to April 1993. Foxes were deterred, di splaced, or tolerated by coyotes in 17, 30, and 53% of the encounters, respectively. Deterrence and displacement of foxes by coyotes occurre d at a similar frequency in the absence and presence of an ungulate ca rcass. Tolerance of foxes by coyotes occurred most frequently in the a bsence of a carcass. A group of coyotes feeding or resting at a carcas s was a deterrent to approaching foxes.