FOOD EATEN BY THE FREE-LIVING EUROPEAN BISON IN BIALOWIEZA FOREST

Rumen contents of the European bison (n = 67) living free in herds within Bialowieza Forest have been estimated. In winters of continuous snow cover, when bison have access to hay offered in feeding racks, their basic food consisted of grasses, sedges and herbs (90.4% per cent of the rumen capacity), with trees and shrubs as supplementary food (9.5% of the rumen capacity). In spring the proportions of these two groups of plants are 88.2 and 11.2%, in summer 86.3 and 13.0%, in autumn 93.2 and 6.7%, respectively. Mosses, horsetails, ferns and fungi combined account for 0.1 to 0.7% of the rumen capacity depending on the season.