Owls as bioindicators: their spatial and temporal aspects in Eastern Europe

The article presents the unique results of a study of the spatial distribution of owls in the territory of the Republic of Tatarstan by season of the year on long-term data. Ravkin’s transect method was used to census fixed randomly selected plots spread over a large geographic area. Abundance a lot of species of owls strong changed of different seasons of the year. In general, owls were indifferent to latitudinal, longitudinal, and altitude gradients in the territory of the Republic of Tatarstan, especially in winter and autumn periods. Probability of occurrences of boreal and pygmy owls can be used as indicators of the biological diversity of forest ecosystems in winter period