Bats (Chiroptera, Vespertilionidae) in Orenburg Oblast

New and old data on all 16 bat species recorded in Orenburg oblast, Southern Urals, Russia, including places and dates of their records, their relative abundances and occurrences, their age and sex compositions, the pattern of their stay, and their distribution, and environmental status, are summarized. The species Vespertilio murinus, Pipistrellus nathusii, Nyctalus noctula, Myotis dasycneme, M. daubentonii, and probably Eptesicusserotinus are particularly widespread and abundant in Orenburg oblast (92.1% of all trapped bats). Two other species, Plecotus auritus and Myotis brandtii, are widespread, but with low abundance (3.6% of all captured individuals). Four species (Myotis davidii, Eptesicus nilssonii, Nyctalus leisleri, and Pipistrellus kuhlii) (3.7%) are rare and distributed locally, and Nyctalus lasiopterus, Myotis nattereri, Pipistrellus pygmaeus, and Myotis mystacinus (0.6%) are very rare. Compared to other Ural regions, Orenburg oblast supports a greater diversity of bats, which is primarily determined by the greater variety of natural and landscape conditions and a more southerly location. The bat fauna of Orenburg oblast, as well as the bat fauna of the Volga region, Cis-Urals, and Urals, are a transboundary Eurasian variant of the East European bat complex, which includes Central Asian species, in addition to European ones. The data of our research indicate that the territory of Orenburg oblast encompasses the range limits of nine bat species. The southern limits of the range are identified for Myotis nattereri, M. mystacinus, and Eptesicus nilssonii, the northern limits for Pipistrellus kuhlii, Eptesicus serotinus, and Myotis davidii, and the eastern limits for Nyctalus lasiopterus, N. leisleri, and Pipistrellus pygmaeus. All the species living at the range borders are rare in Orenburg oblast and recommended for being included in the regional Red Data Book.