Variation of climate conditions is often one of the factors that regulate the population of different animal species in natural ecosystems. Comparison of the population dynamics of species during normal and drought conditions would help to outline the possible influence of changed drought conditions on the development of wild animals. There are many approaches to estimate the population dynamics of wild animals. The correct interpretation of the observed dynamics changes requires good knowledge of ecological and biological features of the species, in which population dynamics is investigated at extreme changes in the climate conditions. The presence or absence of water basins in natural ecosystems is a determinant for certain birds and mammals. The results of comparative analysis revealed a general trend in population dynamics of the studied species during the drought period. Pheasant population dynamics during the drought period exhibited entirely negative changes, although the values varied yearly.