Winter activity and roosts of the noctule (Nyctalus noctula) in an urban area (Central Slovakia) [Zimná aktivita a úkryty raniaka hrdzavého (Nyctalus noctula) v urbánnom prostredí (stredné Slovensko)]
Peter Kaňuch, Martin Ceľuch
Correlation between flight activity of noctule bats and air temperature and habitat features influencing roost-site selection were studied in the prefab buildings estate in the Zvolen town during the season October 2003 – April 2004. Using the ultrasound bat detector, the flight activity of noctules was observed during whole winter period (n=28 surveys). Intensity of relative flight activity positively correlated with average day temperature. Noctules were often flying in temperatures between 0 and –5 °C. In the coolest days, when average day temperature decreased to more than –10 °C, no bat passes were recorded. Altogether, 27 noctule roosts were found, mostly located in the roof attics. There was no preference in the height of the shelter and bats preferred less western, possibly southern orientation of the roosts. It appears that the selection of the roost depends mainly on the general accessibility of the shelters in prefabs. Recorded two movements of banded bats, concerning the study area, broaden the knowledge about the residence and short movements of males during the year and migrating site fidelity in females of the noctules in Slovakia. Predation of bats by the long-eared owl (Asio otus) was observed there.