DENSITY-RELATED HOME-RANGE SIZE AND OVERLAP IN ADULT FIELD VOLES (MICROTUS-AGRESTIS) IN SOUTHERN SWEDEN

At high densities during the non-breeding season, home ranges were half the size of those measured at low densities. Home ranges during the breeding season were considerably larger than those established during the nonbreeding season with high densities, but did not differ in size from those in the nonbreeding season with low densities. Ranges of males generally were larger than those of females. Established voles generally stayed in the same restricted area throughout winter. At low densities, males showed a tendency to change home ranges. With onset of breeding in spring, overwintered individuals usually settled in areas adjacent to their winter ranges. Adult females became distributed according to a territorial pattern in spring, whereas ranges of males still overlapped extensively during the early part of the breeding season. During the nonbreeding season, vole ranges overlapped extensively, especially at high densities, but there was no evidence of group structure with aggregation behavior in any of the sexes. -from Authors