Population dynamics, movement and home range of black-tailed jackrabbits (Lepus californicus) in Curlew Valley, northern Utah. Final report

Abstract

The long-term objective of the jackrabbit study in Curlew Valley, Utah and on the Idaho National Engineering Laboratory was to describe observed changes in rabbit density in terms of mortality and natality rates and to relate changes in these two population parameters to variation in environmental factors. Fall rabbit density in Curlew Valley has been observed to change by a factor of 17; changes appear to be largely determined by variation in mortality rates, as shown with K-factor analysis. Mortality of the population from fall--spring is correlated with the coyote/rabbit ratio. Spring--fall adult mortality and birth-fall loss of juveniles are correlated with coyote numbers. Coyote numbers in the relationships are modified to reflect variation in coyote feeding behavior with changes in rabbit and rodent numbers as indicated by coyote food habits studies in Curlew Valley. Coyote predation rates have varied markedly between years as a result of functional and numerical responses in the coyote population. Proposed coyote predation models, which account for the entire observed jackrabbit cycle, are consistent with existing predation theory.