COMPETITIVE INTERACTIONS BETWEEN COYOTES AND SAN-JOAQUIN KIT FOXES

Competitive interactions between coyotes (Canis latrans) and federally endangered San Joaquin kit foxes (Vulpes macrotis mutica) were invest igated at the Naval Petroleum Reserves in California (NPRC) during 198 4-1995. Coyotes and kit foxes used similar food items, indicating the potential for exploitative competition. Leporids were the primary prey for coyotes in all years, but small rodents mere the primary prey for kit fares in most years, although leporids were primary prey in other years. Coyotes were the main cause of mortality to kit foxes at NPRC, indicating that interference competition may be occurring. Population trends of kit foxes appeared to be strongly influenced by food availa bility, but competition from coyotes also may have affected population dynamics of kit foxes. Mechanisms employed by kit foxes, such as reso urce partitioning, greater dietary breadth, and year-round den use, ma y facilitate coexistence with coyotes. However, use of anthropogenic f ood sources by coyotes may intensify competitive interactions during p eriods of low prey availability.