Operation of predators in a forest and cultivated fields1

Abstract

Ryszkowski, L., Wagner, K., Goszczynski, J. & Truszkowski, J. 1971: Operation of predators in a forest and cultivated fields. Ann. Zool. Fennici 8: 160 — 168. Seven hundred Apodemus flavicollis, 500 Clethnonomys glareolus and 500 Apodemus agrarius were estimated to be present in a 40-hectare forest during one year. About 1 000 Microtus arvalis lived in a 40-hectare band of fields surrounding this forest dur ing the same period. The dietary habits of foxes, martens, badgers, tawny owls and common buzzards were also investigated during the same period. These predators ate about 1 200 forest rodents and 1 100 field voles. The data are preliminary and only in dicate that predation on rodent populations is heavy. The fact that more field voles were eaten than were estimated to be present results from underestimation of the size of the territory hunted by owls and the inaccuracy of the method used to census field rodents.