Food-Item Use by Coyotes at the Naval Petroleum Reserves in California

Abstract

Coyote (Canis latrans) food habits have been extensively documented (Bekoff, 1977). Use of food items by coyotes varies with location and time in response to spatial and temporal variation in food availability. Thus, siteand time-specific investigations are necessary to accurately describe local coyote foraging patterns. Relatively few investigations of coyote food habits have been conducted in California (e.g., Ferrel et al., 1953), and none were specific to the San Joaquin Valley. Additionally, coyotes in the southern San Joaquin Valley are sympatric with the endangered San Joaquin kit fox (Vulpes macrotis mutica = V. velox macrotis, cf. Dragoo et al., 1990) and potentially compete with foxes for food resources. Also, several other federally listed and candidate species occur in the southern San Joaquin Valley and may be preyed upon by coyotes. These species include the endangered giant kangaroo rat (Dipodomys ingens) and the blunt-nosed leopard lizard (Gambelia silus), and candidate species shortnosed kangaroo rat (Dipodomys nitratoides) and San Joaquin antelope squirrel (Ammospermophilus nelsoni). We investigated food-item use by coyotes at the Naval Petroleum Reserves in California (NPRC) to (1) determine annual and seasonal item use, and in particular to evaluate the dietary importance of leporids which are important prey for kit foxes (O'Farrell et al., 1987; J. H. Scrivner et al., in litt.), (2) assess the effect of annual leporid abundance on coyote food habits, and (3) determine whether coyotes prey on giant kangaroo rats, blunt-nosed leopard lizards, shortnosed kangaroo rats, and San Joaquin antelope squirrels. NPRC is an area of active petroleum production located 42 km SW of Bakersfield in western