Ecological structure fauna of nesting birds of steppe ecosystems Baikalian Siberia

There are 213 birds’ species nesting in Baikalian Siberia and 56 (26,3 %) from them are nesting in steppes. Typical species for steppes reach 22 (39,3 %), other 60 % belong to preferential (polytopes) (30 species; 53.6 %) and chanceable (4; 7.1 %) species. The most plentiful is preferential group which consists of birds of intrazonal ecosystems first of all from shrubs community and also eurybiont birds from dendrophil and petrophile zoological complexes. The most of shrubs from researching region came from European and Asian forest-meadow complexes. Steppe shrubs biotopes are attracted to humid border areas of steppes, meadows, forests and ponds with specific conditions. Eurybiont dendrophil species eschew wide steppe areas without trees. Typical steppe species populate different biotopes, but every species prefers own habitat. Nesting of chanceable birds links with attractive places with comfortable conditions near original habitats. The deficit of good choice of favorable places for nesting many species can’t stay in ecotone biotopes and save nesting specific. The most petrophil species are plastic and wide. Baikalian Siberia is situated in ecotone zone “forest-steppe” that is why ecological variety of birds in Baikalian Siberia is much richer than in arid territory of Mongolia.