Bioacoustic evidence for a continuous summer presence of the greater noctule bat, Nyctalus lasiopterus, in the Italian Alps

Abstract

The greater noctule bat, Nyctalus lasiopterus (Schreber, 1780), is one of the rarest bat species in Europe. Data on its distribution in the central and western parts of the continent are largely lacking. For the first time, N. lasiopterus was observed in South Tyrol (Northern Italy) using bat detectors in the summer of 2016 and in the following years until 2021. The five sites where the species was detected are located in a limited area of the Adige Valley, which is characterised by low elevation and a mild climate. Multiple recordings indicated a continuous summer presence of N. lasiopterus on the southern side of the Alps. Additionally, we present insights on echolocation and species identification, including statistically significant differences in the call metrics of N. lasiopterus compared to Tadarida teniotis. These results are important at a European level given that data is lacking on the populations of N. lasiopterus in Europe outside the Mediterranean.