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Young males of Nyctalus noctula (Schreber, 1774) are known to remain immature in the year of their birth in some parts of the species range, but reach maturity in other parts. In the latter case, however, a doubt has been expresses about whether they would be able to mate. We adduce strong evidence that males of the year can really be fertile. In captive noctules, among which there were no old males, copulatory behaviour and parturition were observed. The possible significance of this phenomenon is discussed.
The knowledge about the awakening of hibernating bats is not sufficient. Unknown are also factors affecting the cyclical nature of this process. The aim of the study was to determine the impact of changes of phases of the moon, and thus changes in the Earth's magnetic field on the behaviour of wintering common noctules Nyctalus noctula Schreber. Hibernation of 336 common noctules placed in the hibernation shed was investigated. The shed was equipped with loggers which measured temperature. Based on the temperature changes inside the shed, a drop or an increase in bat activity was determined. Periodicity of temperature increase was observed and it correlated with the current moon phases. The moon phase regarded as the bright referred to more than 70% of moon face illuminated (MFI). The significant temperature increase inside the shed was observed at 70% MFI. This is also when the bats demonstrated an increased activity. The observed differences in the temperature inside the shed during bright nights were statistically significant. The results of the research indicate that moon phases have influence on awakenings coordination in the wintering colony of noctule bat. This phenomenon causes difficulties in interpretation. If bats are in fact able to distinguish moon phases the moon appears to be the perfect tool to control their internal biological clock.
The echolocation calls of the noctule bat Nyctalus noctula {Schreber, 1774) were recorded at night, from June to August 1991, using a QMC S20Q bat detector, in 5 habitats (river, forest-meadow eeotone, village, coniferous forest, deciduous forest) of the Białowieża Primeval Forest (eastern Poland). Two main kinds of signals were identified: search calls and feeding buzzes. Acoustic activity was high over the rivers, in the forest-meadow eeotone and in small woodland villages. It was negligible inside the coniferous and deciduous forests. The differences among habiLats were especially evident in the case of feeding buzzes; no feeding was recorded inside deep deciduous forests. Two peaks in overnight activity were found, with maxima after sunset and before sunrise. Intraseasonal changes of activity were recorded; the highest activity was in July.
Bats were netted at two sites over the forest rivers Narewka and Hwoźna in Białowieża Primeval Forest (E Poland), during the summer of 1994 and 1995. A total of 452 bats of 11 species were captured. The number of bats netted each night was positively correlated with the minimum air temperature. The rate at which the three commonest species - Nyctalus noctula, Myotis daubentonii and Nyctalus leisleri - were caught varied significantly through the night, with a major peak after sunset. For N. noctula air temperature was apparently positively related to the size of the morning peak.
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