Home range overlap and spatial-temporal interactions in female fishers on the Hoopa Indian Reservation in California

Spatial organization and interactions within animal populations can have important effects on population demography, social dynamics, and genetic composition. Understanding social behavior and relatedness of individuals in a population can advise species management and conservation. Previous research suggests that fishers (Pekania pennanti) are asocial and exhibit intrasexual territoriality, where home ranges rarely overlap with the same sex. On the Hoopa Valley Indian Reservation in California, female fishers appear to overlap with members of the same sex to a greater extent than most studies report. I tested the hypothesis that female fishers tolerate some degree of spatial overlap, but that co-occurrence in the area of overlap is uncommon. I also tested the hypothesis that this overlap is mediated by habitat selection and female philopatry. I found that female fishers share a large proportion of their home ranges and overlap at a high frequency. However, dynamic interactions revealed fishers avoided each other in both space and time. Habitat used in overlap areas differed from what was available to them in non-overlapping areas but lacked a consistent pattern of selection among habitat types. I used genetic samples to assess population pairwise relatedness and determined that adult female fishers were more closely related and adult male fishers less related, to each other, respectively. Furthermore, these data showed evidence of male-biased dispersal in this population suggesting female philopatry. Information from this study is important for management of current fisher populations in order to better understand spatial patterns on the landscape needed to guide management for both source and translocation programs used for conservation of this species.