ENVIRONMENTAL-FACTORS INFLUENCING HABITAT EXPLOITATION BY THE POLECATMUSTELA-PUTORIUS IN WESTERN FRANCE

Variation in habitat use was studied by radiotracking 11 polecats Must ela putorius in two wetlands in western France. Habitat selection show ed a clear seasonality. Marshes were the most exploited habitat in spr ing while woods were mainly used in the coldest months and meadows wer e frequented in summer and winter. An analysis of seats showed that di et correlated with habitat utilization. The proportions of bank voles Clethrionomys glareolus, and meadow voles Microtus sp. were, respectiv ely, related to the use of woods and meadows, while amphibians (mainly Rana dalmatina and Bufo bufo) were associated with marshes. Availabil ities of rodents, assessed monthly by trapline success, were also sign ificantly correlated to their occurrences. In contrast, no correlation s were found between larger prey, such as brown rats Rattus norvegicus and rabbits Oryctolagus cuniculus, and any habitats or their abundanc e in the field. The occurrences of these prey and of some minor resour ces, such as shrews and birds, were correlated most with meteorologica l factors. The exploitation of marshes and amphibians increased when s mall rodents declined. Therefore, in the polecat, habitat selection wa s mostly influenced by trophic factors. Dietary diversity was greater in spring when food resources decreased, suggesting that polecats were optimal foragers. The study has emphasized that the polecat is a gene ralist feeder.