Based on the published findings (Koštejnová 2013, Slezáková 2014, Gajdošík 2020), unpublished data from museum specimens (2005 – 2013), and data from field surveys (2005 – 2023), a total of 13 bat species were recorded in the urban area of Ostrava in North Moravia. Common species in the area included Pipistrellus pipistrellus, Nyctalus noctula, Eptesicus serotinus, Myotis daubentonii, and Vespertilio murinus. P. pipistrellus was eudominant species (D = 74.41), followed by N. noctula (D = 11.41). E. serotinus was a subdominant species (D = 4.59), followed by M. daubentonii (D = 3.77) and V. murinus (D = 2.45). The occurrence of M. mystacinus/brandtii was recendent (D = 1.33), and the occurrence of M. nattereri (D = 0.51), E. nilssonii (D = 0.51), P. pygmaeus (D = 0.31), Plecotus auritus/austriacus (D = 0.31), Pipistrellus nathusii (D = 0.20), N. leisleri (D = 0.10), M. myotis (D = 0.10) and M. brandtii (D = 0.10) were subrecendent. In the summer season, eudominant species were P. pipistrellus (D = 76.84), followed by the N. noctula (D = 10.63), subdominant E. serotinus (D = 4.74), and M. daubentonii (D = 3.89), with M. mystacinus/brandtii being recendent (D = 1.37). In the winter season, eudominant species were V. murinus (D = 62.50), followed by the N. noctula (D = 34.38) and subdominant P. nathusii (D = 3.13). However, the species composition inside and outside buildings differed significantly. In the summer season, eudominant species inside buildings was P. pipistrellus (D = 99.57), followed by the subrecendent species V. murinus (D = 0.29) and M. daubentonii (D = 0.14). Outside buildings, N. noctula (D = 40.16) were eudominant, followed by E. serotinus (D = 17.72), P. pipistrellus (D = 14.17), and M. daubentonii (D = 14.17), with M. mystacinus/brandtii (D = 5.12) was dominant, and M. nattereri (D = 1.97), E. nilssonii (D = 1.97), P. pygmaeus (D = 1.18), and P. auritus/austriacus (D = 1.18) were recendent species. In the winter season, eudominant species inside buildings were V. murinus (D = 68.75), followed by N. noctula (D = 25.00), and the situation was very similar outside the buildings during this period, with eudominant V. murinus (D = 56.25) and N. noctula (D = 43.75). Two roosts of the maternity colonies P. pipistrellus were recorded in city buildings: in Výškovice, Lumírova 10, in a expansion joint near the balcony on the top floor of a panel residential building; and in Zábřeh, Plzeňská 2617/4 and Plzeňská 2617/6, in expansion joints on the top floors of an old panel building used as a hostel and apartment building.
