Response of bank voles to a new source of food and its withdrawal

Abstract

The response of bank voles Clethrionomys glareolus (Schreber, 1780) toward a new source of food and its later withdrawal was studied in a forest environment. Oat grain was used as a kind of food new to rodents in this natural habitat. The process of finding such new supply of food was studied in five groups of stations (23 in each) where oat grain was offered in 1 to 5-day periods. The response of voles toward withdrawal of the food source was studied in four groups of stations (again 23 in each) with variable time passing between food withdrawal and subsequent removal of rodents by snap traps. In the control group of 23 stations no oat grain was offered. The numbers of voles assessed by a regression line for subsequent days of trapping in stations without oat grain and in those where oat 'meals' were offered 1 to 4 days did not differ. It suggested rather rapid location of new food source. In 5th day there was an increase in numbers of voles coming to the sites with food offered. In the second part of experiment, i.e. this designed to assess the response of voles toward withdrawal of food source, the regression analysis revealed variable numbers of voles: the longer time passing from food withdrawal, the lower number of voles frequenting the site compared with the control sites, i.e. some voles avoided, for couple of days, the sites where new food had been withdrawn.