RESPONSE OF RODENTS TO AN INCREASED AND QUANTITATIVELY DIVERSE FOOD BASE

The response of Clethrionomys glareolus (Schreber, 1780), Apodemus flavicollis (Melchior, 1843) and Apodemus agrarius (Pallas, 1771) to a short-term increase and quantitatively diversified food base was studied in the Mlociny Forest in Warsaw in four areas situated in an alder swamp. The additional food for the rodents was oats laid 3 days before catching the animals at a number of points situated 15 m apart. Test areas differed in the amount of oats, with 70, 30, 10 or 1 points of oats. This additional food was consumed by 98% of the caught rodents in which oats was found in the stomach. In all rodent species the contents of the stomach was positively correlated with the per cent of oats in the food. The greatest percent of oats in gastric contents was found in all species in the areas with the greatest number of oat points. The number of rodents feeding at one oat point was inversely proportional to the number of oat points in a given area. The number of rodents caught near a given oat point was higher in the area with a small number of points than in the areas with much additional food.