Birds' Population of rock outliers of Ubsu-Nur hollow

The aim of the study was to investigate spatial and biotopical location, species composition and population density of rock pillar birds at the Ubsu-Nurskaya basin. Almost all the largest rock pillars located within Erzinsky steppe subarea of the Ub-su-Nurskaya basin were explored, as well as the number of smaller (mainly to the south-east from the Agar-Dag low-mountain range). The species composition and population density of rock pillar group of birds were determined in comparison with rocky habitats along the basin floor borders at the submountain region of the surrounding ranges. It was revealed that intrazonal environment forming rock pillars and rock pillar ranges attracted 47 birds' species of different ecological groups for nesting, including 26 petrophylous species and 14 shrubby birds. Rock pillar petrophylous species prefered southern cliff sides and rocky hills of different scarp, while northern cliff sides were occupied mainly by shrubby birds and steppe species. It was estab-lished that 16 species were fixed group of Ubsu-Nurskaya basin rock pillar bird population. Average birds' population density of different ecological groups was 505 birds per km2, 366 birds per km2 (72.5 %) fall to the share of petrophylous species. Surrounding landscape features had significant impact on the structure of rock pillars. So, the share of shrubby and steppe species in birds general population density located in semidesert did not exceed 19.4 % and in karagan steppes this index reached 33.7 %.