Home ranges and social organization of syntopic Peromyscus boylii and P. truei

Abstract

Using radiotelemetry, we investigated sizes, spatial distributions, and overlap patterns of home ranges for two syntopic populations of Peromyscus boylii and P. truei. Home ranges were calculated from the minimum convex polygon (MCP) and the fixed-kernel-density estimator of radiolocations from 3 summers in northern New Mexico. During each summer, these Peromyscus exhibited a seasonal cycle in abundance, starting low in early summer and increasing through the summer months. Both estimates of home-range size were correlated significantly, although the fixed-kernel-density estimates were usually larger. Home ranges of male P. truei were larger than those of female P. truei and male and female P. boylii. The disproportionately larger size of ranges of male P. truei was likely due to distribution of female P. truei, which were more dispersed than female P. boylii. The MCP home ranges of male P. boylii also were larger than home ranges of female P. boylii. Both species' home ranges were related inversely to conspecific density, but only home ranges of P. truei varied inversely with heterospecific density. Females of both species tended to overlap little intrasexually; males had home ranges that overlapped home ranges of multiple females and males. Patterns in home-range size and overlap were consistent with a promiscuous mating system for both species.