Factors Affecting Activity Patterns of the Whiskered Bat Myotis mystacinus (Kuhl, 1817) (Chiroptera: Vespertilionidae) in the Western Carpathians, Poland

We applied radio-telemetry on 21 individuals (10 females and 11 males) to provide data on the temporal activity patterns of the whiskered bat (Myotis mystacinus) in the Carpathian Mountains (southern Poland). We tested whether sex, season and weather conditions affect their activity patterns in July-September. On average, whiskered bats left day roosts 18.9 minutes after sunset and returned to roosts 198.1 minutes before sunrise. The mean length of activity was 330 minutes (SE±25) per night. Bats were active mainly (85%) during the whole night; they rarely (15% of nights) interrupted foraging and returned to their roosts for 10-60 minutes. Their activity peaked between the 2nd and the 3rd hour after sunset, when 76% of individuals foraged. Duration of activity varied between sexes. In females, it was one hour longer and noticeably increased from July to August. Males, but not females, shortened their activity again in September. However, due to high individual variation, differences in activity patterns between sexes were insignificant. Mean night temperature (positive effect) and duration of rainfalls (negative effect) best explained the variation in whiskered bats’ activity. Our study delivered further evidence of the importance of weather conditions for the foraging activity of insectivorous bats in temperate environments.