Large hibernating aggregations and behaviour called late summer or autumn “invasions” when large groups of bats enter buildings are known in pipistrelles. We investigated differences in roosting behaviour between two cryptic species (common pipistrelle, Pipistrellus pipistrellus, and soprano pipistrelle, Pipistrellus pygmaeus) during autumn and winter periods. In total 463 bats were sampled in both caves and buildings with temporary occurrence during the period of late summer and autumn mating and presumable migrations from late July to September (10 sites), and in all known types of hibernacula from late November to March (34 sites). Sampling sites were located within the Czech Republic, Slovakia, Serbia and Romania in areas where the two species occur sympatrically throughout the summer. Using a DNA-based identifi cation method, all but four individuals were identifi ed as P. pipistrellus. It means that winter roosts of P. pygmaeus remain largely unknown in the area. Similarly, no P. pygmaeus was found in the “invasion” assemblages. Very abundant groups of P. pipistrellus in underground hibernacula and its exclusive occurrence in sites of “invasions” suggest that roosting behaviour during this time may be species-specifi c.
White-nose Syndrome (WNS) decimates bat populations in North America but similar effects have not been recorded in Europe. WNS-affected bats exhibit abnormal hibernation behaviour that prematurely deplete fat reserves and ultimately causes death by starvation. In the deep hibernation period (December-March) of 2006/07 (pre-WNS) and 2010/11 (post-WNS), we monitored bat hibernation behaviour and flight activity to test the potential impact of WNS on European bats. We registered no abnormal changes in bat hibernation behaviour (movement to visible sites, utilization of dynamic cave sections), flight activity level, its direction or seasonal pattern remained unchanged following WNS infection. Flight activity inside the cave and at its entrance was generally low during the deep hibernation period and temperature remained the best predictor of activity level. In general, stable hibernation behaviour and activity patterns suggests that they are apparently optimized for European winter conditions and support the hypothesis that the fungus has been present in Europe for a long time and has only recently invaded North America.
Studies were made of the shape, volume and depth below ground level of hibernation cavities used by free-living and captive edible dormice, Glis glis (Linnaeus, 1766). Most of the cavities (77 out of 83) were occupied by a single animal. Sixty of them had a characteristic oval shape and were analysed in detail. The volume of cavities in free-living dormice ranged from 429 cm3 to 1174 cm3 (median = 670 cm3, Q1 = 605.5 cm3, Q3 = 855 cm3, N = 17) and in captive animals from 293 cm3 to 2211 cm3 (median = 837 cm3, Q1 = 571 cm3, Q3 = 1055 cm3, N = 43). No correlation between body mass of hibernating dormice and volume of their cavities was found. A tendency for male cavities to be larger than female ones was evident, although the differences were not statistically significant. Comparison of volumes of cavities made by free-living versus captive dormice, as well as captive adults versus subadults also did not reveal significant differences. Cavities of free-living dormice were found between 18 and 70 cm underground (median = 30 cm, Q1 = 25 cm, Q3 = 40 cm).