HOME-RANGE, POPULATION-STRUCTURE, AND SPATIAL-ORGANIZATION OF CALIFORNIA GROUND-SQUIRRELS

Home-range size and spatial organization were described for a population of California ground squirrels (Spermophilus beecheyi) in which maternal relationships and residence time were known for individuals. Home-range sizes as determined by harmonic-mean transformation for female California ground squirrels were similar to those reported for females of some populations of sciurids, but the home ranges of males were smaller than those reported for other spermophile males. Home-range sizes of females were larger than those of males. No significant difference in size of home ranges of males was detected between breeding and postbreeding seasons. Neither females nor males had exclusive use of their home ranges. More female yearlings established burrow systems near their natal burrows than did males. Each young female that was retrapped as a yearling had established a home range adjacent to or overlapping that of her mother. After establishing burrow systems as yearlings, adults typically exhibited multiyear site fidelity. Both females and males probably lived near descendent kin.