ON THE COLONIAL STRUCTURE OF BRANDT'S VOLE IN BURROW UNITS

Abstract

The colonial structure of brandt's vole(Microtus brandti Radde) in different dens varies from year to year and season to season, affected by such factors,as reproduction and the others.Its changes include main- ly the size of itsfamily and the proportion of each category within its family members. The Brandt's vole in Hulunbeier grassland had a larger family size in 1974 when its density was increasing, A family occupying burrow unit consisted mainly of parents and their offspings of one litter for the most part of the year. But in summer and autumn, some times it consisted of parents and their offsprings from two litters. However, in 1975, the vole had high population density but a smaller family size which contained parents and offsprings from one litter.The number of males were more than that of females in 1975.