THE SIGNIFICANCE OF CEREAL STUBBLE AND MANURE HEAPS FOR BIRDS WINTERING IN THE FARMLAND OF EASTERN POLAND

The presence of wintering birds on manure and stubble was studied in the open farmland of eastern Poland. Among the 34 species recorded during transect surveys, 13 were on manure heaps and 16 in stubble fields. Species diversity did not differ significantly between these habitats but there were differences in the densities of individuals. Snow depth had a positive influence on the birds observed on manure heaps but had a negative impact on those associated with stubble. Logistic regression analysis showed that birds selected manure heaps with larger surface areas and larger areas of fresh manure, but that the duration of manure heaps did not affect their choices. This habitat can be used as an alternative food source and roosting site during long-lasting snow cover. This has been particularly important for the yellowhammer Emberiza citrinella, whose Polish breeding population is one of the largest in Europe.