Home-range attributes and spatial structure of woodchuck populations [Caractéristiques des domaines vitaux et structure spatiale des populations de marmottes des bois].

Résumé

Movements and patterns of burrow use by woodchucks (Marmota monax) in two Connecticut orchards were determined from 734 captures of 273 individuals and l,213 radio locations of 46 individuals. All data were collected after the breeding season. Adults occupying home ranges used an average of eight burrow systems; males occupied home ranges l.8 times larger than females. Burrow systems were located disproportionately often along woodland edges and brushy fence rows, and use of these areas was two-three times greater than expected based on their availability. Populations were loosely structured spatially. Territoriality may occur at occupied burrows. Although rare, simultaneous use of a burrow usually involved an adult male and a reproductive female. Overlap of home ranges of reproductive females and males was relatively large (36%). Although woodchucks are less social than other marmots, data from this and other recent studies lead me to suggest that a limited amount of social cohesion or tolerance may extend beyond the periods of breeding and weaning. I hypothesize that the prevailing social structure of woodchucks may partly reflect phenotypic responses to a diffuse distribution of resources engendered by the agricultural activities of humans.