The influence of weather on birds wintering in the farmlands of eastern Poland

摘要

Counts of wintering birds were conducted in the extensively cultivated farmland of eastern Poland during three seasons. The number of wintering species of birds was negatively correlated with the depth of snow and positively related to the number of species recorded during the previous count. The total number of birds was negatively correlated with the depth of snow cover and positively correlated with the total number of birds recorded during the previous count. To a great extent it was the presence of snow cover that shaped the assemblages of birds wintering in farmland. During long-lasting snow, birds may leave this type of landscape. At wintering grounds influenced by conditions similar to those in eastern Poland the depth of snow may be of greater importance for birds than the presence of suitable feeding habitats because food is limited. As a consequence of the global climate change, changes in snow cover will occur and should increase the numbers and abundance of bird species wintering in eastern Poland.