Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Wildland Resources

Committee Chair(s)

Frederick F. Knowlton


Frederick F. Knowlton


I measured three variables of coyote-food base relationships in Jackson Hole, Wyoming, during t he period Jul y, 1973, to July, 1975. Field work provided estimates of relative coyote and prey abundance as well as observations on coyote feeding behavior during winter. Laboratory analysis of 1,500 coyote scats reveal ed feeding patterns while feeding trials with captive coyotes allowed refinement in interpretation of scat analysis.

Deer mice and chipmunks comprised most of the rodent biomass captured in traps in the fall, while ground squirrels accounted for much of the rodent biomass in the spring. Field voles declined from 1973 to 1974 throughout much of the study area.

Northern pocket gophers, field voles, and Uinta ground squirrels were the principal foods in the May-October diet of coyotes. They fed primarily upon ungulate carrion during winter.

Because substantial differences in weight between adult and juvenile ground squirrels and pocket gophers make age classification important in calculating biomass, I developed a technique for identifying age classes based upon measurements of tooth remains in coyote scats. Feeding trials with captive coyotes indicated that heavier prey are detected in scats more often than lighter ones. Differences in weight multiplied by differences in detectability for the three principal rodents varied by factors of 1.1 to 2.6.

Carrion from hunter-killed and winter-killed elk supplied food for coyotes from October to May. The abundance and temporal availability of carrion varied substantially between areas.

Up to six-fold differences in coyote population indices occurred between areas. These differences were attributed primarily to differences in the amount of ungulate carrion available during winter. The possible influence of nutrition upon coyote natality, mortality, and movements are contemplated.