[Abundance of Trans-Volga population of the great bustard (Otis tarda L.)].

We studied the abundance, spatial structure, and democratic parameters of the Trans-Volga population of great bustard as well as this species connection to the habitats during premigratory movements. The data were obtained by monitoring a test area of 1,200,000 hectares in 1998-2000. Time-related changes in the structure of great bustard habitats in Saratov Trans-Volga Region during the 20th century are described and the mechanisms underlying the changes in this species connection to the habitats under the influence of anthropogenic factors are proposed.