Home – Home – Jornals – Contemporary Problems of Ecology 2002 number 5

Materials of all-year-round censuses of birds carried out by the author in the Visim reserve territory and in its protected zone in six habitats from December 1983 to November 1984 have been analyzed. With the help of classification of ordered objects, 6 general seasonal periods have been distinguished: relative winter stabilization; pre-spring migrations and beginning of arrival; nesting on the background of local and remote migrations; post-nesting local migrations and beginning of departure; departure and autumn flight; end of flight and pre-winter migrations. A concise quantitative characterization of the periods is given. With the help of non-metrical gradations, 4 types of intra-annual time course of ornithological complexes have been distinguished. Comparison with the available literature data has demonstrated that in the Middle Urals, northern forest-steppe of the Circum-Ob region, the Central Altai and in the deserts of Turkmenistan, the intra-annual stability of the physiognomy of ortnithocomplexes decreases from settlements and forests towards half-open and open habitats, and the intra-annual similarity of forest ornithocomplexes decreases from southern taiga to desert tugais. In the Ural, the abundance of settled species is relatively high, and the change of population aspects is determined by nesting migratory species. In the forest-steppe and especially in tugais, the proportion of species staying during the non-nesting time (migratory, wintering) is considerably higher, which is just what determines the increase of interseasonal differences between the bird population variants. By the character of seasonal variability of bird populations, the ornithocomplexes of the south of boreal vegetation zones and of the desert zone differ in the time of change of periods. Besides, the ornithocomplexes of tugais is characterized by a strong intra-annual differentiation.