Temporal Patterns in the Home Ranges of Chipmunks (Eutamias)

Abstract

An observational study of chipmunks in Montana during two con secutive summers revealed marked changes from week to week in the sizes and shapes of the summer ranges of many individuals, and in the intensity of use of sites within the boundaries. The two most important factors responsible for such change were reproduction and the dispersion of the plants selected for food. The total summer range of most individual chipmunks remained the same from one summer to the next, and changing use within the observed boundaries was predictable and orderly for phenologically equivalent time spans of both summers. Such predictability substantiates the classical concept of home range. However, such changes, if they occur in most populations of small mammals, would necessitate time-qualified expressions of home range.