Abundance of food supply and size of the bank vole's home range

Abstract

Comparison was made of the size of the home range for males and females of different ages in a vole population, Clethrionomys glareolus (Schreber , 1780), both when the population lived on the natural food supply (1967), and when this supply was increased (1973) by constant supplementary feeding with oats. The population lived on a wooded island 4 ha in extent in a lake. Population parameters were recorded by means of the CMR method, and the size of the home range wa s estimated by Wierzbowska's method (1972). The method used for estimating the size of the home range revealed an increase in the size of the home range in 1967 with successive captures of individuals, but in the year with supplementary feeding home ranges maintained a constant size with successive captures, and were smaller. Decrease in the size of the home range does not, however, compensate for increase in the degree to which the home ranges of individuals overlap in a population, as a result of increase in its density in 1973. It was shown in 'the discussion that the decrease in the size of the home range took place as a result of the limitation of great distance wandered by individuals from the centre of their activity. The size of the home range decreases from spring to autumn and the successive generations entering the population continue to have smaller home ranges than those of the older generations up to the autumn, both with the natural food supply and also when this supply was artificially increased. [Inst. Ecol., Polish Acad. Sci., Dziekanów Leśny, 05-150 Łomianki Poland.]