Bioacoustics of Hypsugo savii

Activity patterns. Savi’s Pipistrelles emerge immediately after sunset, or sometimes even before it. Activity is higher during the first and last part of the night, but occasionally they can forage all night if needed. Flight pattern is straighter and more predictable than in Pipistrellus spp. , faster and with fewer changes of direction. Roosts are usually in rock crevices, under bark or in man-made structures; occasionally, they are in the entrances of caves or under rocks on the ground. During winter, this species hibernates in underground sites. Echolocation has QCF calls of ¢.16 milliseconds, with pulse rate of 7-8 pulses/second while foraging and 3-4 pulses/second when commuting. Frequencies of maximum energy are 30-35 kHz, higher than in the Northern Serotine, with a small overlap with Kuhl's Pipistrelle ( Pipistrellus kuhliz). Although reported to have very distinctive social calls with ascending frequency pulses, it is now known to have a broad range of social calls which are used in different circumstances; thus, its identification through social calls is less reliable than was previously thought.