WINTER HABITAT SELECTION AND FEEDING-HABITS OF POLECATS (MUSTELA-PUTORIUS) IN THE BIALOWIEZA NATIONAL-PARK, POLAND

Polecats (Mustela putorius), that inhabited the pristine mature forest s, were studied by means of snowtracking on 11.2 km2 during 5 winters (1985/86-88/89 and 1990/91). They preferred wet habitats: riverside as h-alder forests and bog alderwoods. Drier forests (oak-linden-hornbeam and spruce-pine stands) were used by polecats less frequently than wo uld have been expected from their occurrence in the study area. The in tensity of polecats' use of habitats changed with winter weather. On r elatively warm days (0 to -5-degrees-C ) polecat tracks were recorded twice as often in wet forests as in the dry ones. At temperatures from -6 to -10-degrees-C, this ratio approached 1:1, and below -10-degrees -C, when most of the running and stagnant waters were frozen, polecat tracks were found in drier forests twice as frequently as in wet fores ts. The diet of polecats was studied by an analysis of 222 scats colle cted during 5 winters (1986/87-1990/91). Anurans (mainly Rana temporar ia) comprised 70 to 98% of the biomass consumed by polecats and were f ound in 60 to 95% of scats. Forest rodents (Apodemus flavicollis and C lethrionomys glareolus) constituted from 1 to 29% of the biomass eaten by polecats. The consumption of rodents grew with decreasing winter t emperature and increasing numbers of rodents. Snowtracking of individu al polecats showed that in wet forests, the polecats moved in close pr oximity to water courses and searched for anurans, whereas in the drie r forests, they hunted rodents, mainly by digging.