Bat activity and bat migration at the elevation above 3,000 m at Hoher Sonnblick massif in the Central Alps, Austria (Chiroptera)

Abstract

Recent studies on the presence and activity of bats at high elevations show, surprisingly, that large numbers of bats cross the Alps up to 2,500 m a. s. l. This study takes the next step: to investigate bat activity at an elevation above 3,000 m a. s. l. The main study site was located on the top of Hoher Sonnblick at 3,106 m a. s. l. (Salzburg, Austria). Bat activity was monitored during September and October 2014, and permanently from March to November 2015, with an automated recording device. To compare bat activity at a lower location, a study site at 2,273 m a. s. l. was also monitored from May to October 2015. Contrary to our expectations, we found bats present at 3,106 m from mid-April to mid-September. However, periods of bat activity at these high altitudes were shorter than at lower elevations and were interrupted by longer periods with no activity. Among the recorded species there were all the long-distance migrants in Europe: Nyctalus leisleri, N. noctula, Pipistrellus nathusii and Vespertilio murinus. Eptesicus nilssonii, a predominantly sedentary species, was also recorded on the mountain top as well as Pipistrellus pygmaeus. Bat activity was linked to milder weather conditions. However, we did record bats at wind speeds of up to 12.2 m/s and temperatures as low as –2.1 °C.