Data on the hibernation sites of bats in the European part of the USSR

Strelkov, P. P.

The specific composition, distribution, and numerical data on hibernating bats in 36 caves of the Ural, Central and Lower Volga region, and northwestern and central regions of the European part of the USSR are given; altogether 53 caves were inspected. The caves and their microclimate are described. Six basic spp. of hibernating Chiroptera were distinguished: lake bat, water bat, whiskered bat (Myotis), Natterer's night bat, Plecotus auritus, and northern rattlemouse (Vespertilio). All 6 spp. hibernate in the Sablinsk caves in the Leningrad oblast. The largest numbers of hibernating bats are found in the Urals. Hibernation sites of Vespertilio were also found in caves near Kiev, and in city buildings in Khar'kov, Poltava, and other cities in the Ukrainian SSR. Hibernation sites of the European wide-eared bat (Barbastella) were also discovered in the vicinity of Kiev. The coldest caves in the Ural and in the northwestern part of the European USSR, with a temperature of 2[degree] and lower, are populated by Plecotus auritus and northern Vespertilio. The relative air-humidity in the caves varies from 80-100%. Plecotus auritus and Vespertilio usually hibernate individually; Myotis do not form such dense groups as lake night bats (Myotis). The density of the bats' concentration depends on the season as well as on the number of bats in a cave. Publications on the migration and sedentary habits of bats are discussed. The author considers the bats found in the caves of the central and northern parts of the European USSR as a minor part of the population which hibernates there, attracted by suitable microconditions. But most of the species of bats undertake long migrations. Sites of mass hibernation were found only in the Urals and in the northwestern part of the USSR.