Habitat preference and activity of the noctule bat Nyctalus noctula in the Białowieża Primeval Forest

The echolocation calls of the noctule bat Nyctalus noctula (Schreber, 1774) were recorded at night, from June to August 1991, using a QMC S200 bat detector, in 5 habitats (river, forest-meadow ecotone, 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 ecotone and in small woodland villages. It was negligible inside the coniferous and deciduous forests. The differences among habitats 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.