The raccoon Procyon lotor is an invasive species inhabiting Europe and its impact on local populations, particularly on endangered species, is not well known. The aim of the study was to determine whether raccoons pose a threat to bats wintering in the Nietoperek nature reserve, one of the largest hibernation sites in Central Europe. In the winter of 2016–2017, 67 raccoon scats were collected in one of the main underground corridors in the reserve. It was confirmed, with the use of molecular methods, that the scats belonged to raccoons. Raccoon prey was identified based on the features of skulls, jaws or hair found in the scats. Analysis of the determinable remains indicates that bats (including Daubenton’s bat/Natterer’s bat/Brandt’s bat M. daubentonii/nattereri/brandtii, Natterer’s bat Myotis nattereri, greater mouse-eared bat Myotis myotis, brown long-eared bat Plecotus auritus) made up the largest percentage of raccoon diet (96%). Remains of other mammal species, lizards Lacerta spp., plant materials and anthropogenic food were also identified in raccoon scats. The results of the research indicate that predation by raccoons can constitute a significant factor in the increasing mortality of bats wintering in Nietoperek.

Bat wings are characterized by high endurance, and these mammals have developed a number of adaptations that protect them from falling into obstacles and potential injuries. However, in bat populations, there are individuals with visible fresh or healed injuries to the flight–enabling body parts. The aim of this research was to determine the differences in the occurrence of wing membrane damages among species of bats that differ in ecology and behavior. The study was conducted in southern and western Poland in the years 2000–2016 and included 3,525 individuals of six species: lesser horseshoe bat Rhinolopus hipposideros , Daubenton’s bat Myotis daubentonii , Natterer’s bat Myotis nattereri , greater mouse–eared bat Myotis myotis , western barbastelle Barbastella barbastellus , and brown long–eared bat Plecotus auritus . In all, 2.9% of the bats studied showed damage to the flight–enabling body parts. Natterer’s bat was the species with the highest number of injured individuals (21.74%). The lowest number of injured individuals (0.3%) was found in the brown long–eared bat. The most frequently observed type of damage was loss of an edge of the wing membrane (29.3%). The bat species studied differed significantly in the occurrence and location of flight enabling body parts damages. Certain behavioral and ecological factors like foraging mode, foraging habitats and habitat types of bat species determine the number of wing and tail membrane damages.