MASS MIGRATIONS AND DEATH OF MICROTUS SOCIALIS PALLAS, 1773 IN NORTH-WEST OF PERI-CASPIAN REGION
In the North-Western Caspian region (Republic of Kalmykia), a drastic increase in numbers and distribution of the social vole was recorded in 2014-2016. Average multi-year dominance index of voles in the community of rodents has increased three times in 2014-2016, as compared to 2002-2010. The population growth was determined by the increased intensity of reproduction under favorable climatic and food conditions. In May 2016, a mass migration and death of social voles was observed in some regions of Kalmykia. It is rare for rodents phenomenon caused, probably, by the overcrowding. In the migration process were involved, first of all, males, due to increased intraspecific competition, the increased level of aggression, and less home range fidelity as compared to females. Mass migration and death of social voles in the North-Western Caspian region can be a result of non-stationary dynamics of local grazing ecosystems caused by of the rapid changes in human impact and land management, combined with the climate humidification.