The food habits of deer in the Białowieża Primeval Forest

Abstract

Observations of the traces left by roe deer Capreolus capreolus and red deer Cervus elaphus visiting and feeding in 60 experimental areas (3 ha) were made twice every month over a period of 3 yr in different forest associations. The extent of feeding on different species of plants and variations in food preferences depending on the ecosystem, age class of the tree stand, season and plant abundance were examined [in Poland]. The food of deer includes trees, dwarf-shrubs and 63% of the species of dicotyledonous forbs, grasses and sedges occurring in the experimental areas. Trees included in the basic food of deer are Carpinus betulus, fraxinus excelsior, Quercus robur and Salix caprea, while the dicotyledonous forbs most commonly eaten are Ranunculus repens, Caltha palustris, Filipendula ulmaria, Aegopodium podagraria and Impatiens noli-tangere. The greater the coefficient of abundance of a plant, the greater the percentage it forms in the animals' diet. Intensity of feeding varies over the course of the year, with intensification in summer and winter and depressions in spring and autumn. During the winter trees form 85.sbd.95% of the animals' food. Deer feed chiefly on the younger age classes of tree stands, i.e., plantations and thickets. Preferences for the different age classes varies over the course of the year and is characteristic of the different ecosystems. Dicotyledonous forbs are particularly preferred in the generative stage. One of the ways in which deer obtain food is by stripping the bark from trees and shrubs, the species most frequently barked being Picea excelsa, Tilia cordata, robur and excelsior. An examination was made of the connections between the animals' activity and intensity of feeding in winter. There are only slight differences in the penetration of ecosystems by roe deer and red deer, but considerable differences in the amount of food consumed in them by these 2 species. Examination was also made of the effect of the depth of the snow cover on the activity of the deer. Snow cover deeper than 50 cm limits the roe deer's activity, and snow deeper than 80 cm limits that of the red deer.