Spacing behaviour of red squirrels, Sciurus vulgaris: variation between habitats and the sexes

Abstract

Home range size, range use and range overlap of adult male and female red squirrels in a coniferous and a deciduous woodland were studied using radio-telemetry. Hypotheses, concerning (1) resource predictability and territorial behaviour, and (2) sex-related and habitat-related differences in spacing strategies were tested. In both habitats males had larger home ranges than females. Range size varied seasonally, tending to increase in April–June and to decrease in winter. Both males and females had intensively used core-areas (70% of all locations) that were much smaller than their total range. Dominant males had larger ranges than subordinates, and male body weight was positively correlated with home range size. For females, range size was inversely correlated with food abundance (coniferous area) or local density (deciduous area). Core-area overlap within a sex was smaller than that between sexes. Dominant females defended exlusive core-area overlap within a sex was smaller than that between sexes. Dominant females defended exclusive core-areas against other females, while subordinates behaved as floaters or settled on the edges of the ranges of dominant females. In the deciduous woodland squirrels had larger home ranges, used significantly larger and more strongly overlapping core-areas and were more tolerant of conspecifics than in the coniferous woodland. The results support the hypotheses that (1) the predictability in time and space of food resources, and (2) sexual differences in key resources used to increase reproductive success in mammals with promiscuous or polygynous mating systems, cause differences in spacing behaviour between habitat types and between adult males and females.