SPACING BEHAVIOR AND KEY RESOURCES - AN EXPERIMENT ON SEASONAL PREFERENCE OF MALE BANK VOLES, CLETHRIONOMYS-GLAREOLUS, FOR FOOD AND FEMALES

We studied experimentally male distribution in relation to key resourc es, food and females, during winter and at the onset of breeding in ei ght enclosure populations of the bank vole Clethrionomys glareolus. In the experiment we manipulated the social environment of individuals u nder thick snow cover. After we had determined the male movements in a mixed population of both sexes all females of each enclosure were cap tured and kept in a cage at one end of the enclosure while food was of fered in the opposite end. Male movements between these two patches we re monitored by life-trapping under the snow. We found a seasonal patt ern in the distribution of males in relation to key resources. 1) Duri ng the non-breeding season the manipulation of female and food distrib ution did not affect the male movements significantly, but 2) as expec ted, at the onset of breeding females were the preferred resource for the males. The results are discussed in the light of survival and mati ng strategies of males.