Bioacoustics of Pipistrellus pipistrellus

Activity patterns. Common Pipistrelles emerge c.20 minutes after sunset, and even earlier during warmest nights, with other species of Pipistrellus . Between May andJune, they emerge soon after dusk and return between midnight and dawn, showing a unimodal activity pattern. In late June, activity becomes bimodal, with one peak after dusk and another one before dawn. Flight is slow, erratic, and quite unpredictable, usually following linear structures and hunting with rapid and frequent dives. Roosts occur in a wide variety of natural and artificial structures (e.g. rock crevices, empty cavities in buildings, hollow trees, or under tree bark). The Common Pipistrelle is quite adaptable and resilient in urban-modified environments. Maternity roosts have been reported in buildings, trees (different types of forests), bridges, and wall crevices. Hibernation occurs in cliffs, old buildings, churches with wide walls (behind cladding), caves, mines, cellars, tunnels, and potentially also hollow trees, usually from late autumn to early spring. Echolocation calls are generally rather FM, especially in cluttered environments, but they shift to QCF calls in open spaces (pulses up to 10 milliseconds). Frequencies of maximum energy are42-51 kHz. Calls vary substantially depending on environmental clutter. Social calls usually have 4-5 trills, with lower frequency than search pulses.

Pipistrellus as currently defined is paraphyletic with a Western and an Eastern clade. The Western clade includes all European and African species (FP. pipistrellus , P. pygwaeus,- P cveticus, P hanali, P nathusé, P. maderensis , P. kuhlu, P. hesperidus , P. rus-Yicus, P. nanulus , P. inexspeciatus, P. ae, P. permixtus , and P. raceyr); the Eastern clade includes all Asiatic species (FP. dhofarensis, P. abramus , P. endou, P. sturdeei , P. javanicus , P. cooomandra, P. ceylonicus , P. tenuis , P. paterculus , P. stenopterus , P. minahassae , P. collinus , P. papuanus , P. angulatus , P. wattsi , P. westralis , and P. adamst), although this is a rather broad definition because not all currently recognized species are sequenced. The Eastern clade seems to be closely related to Glischropus ; the Western clade is closer to Nyctalus with Vansonia (previously included in Pipistrellus ), sister to the entire clade. During the 1980s and the 1990s, P. pipistrellus was split into P. pipistrellus and P. pygmaeus based on acoustic surveys, in which two different frequency bands were detected. Because of recent taxonomic changes, their distributions and conservation status are still debated. All records and phylogenetic analyses support the hypothesis that P. pupistrellus expanded into Europe from the Mediterranean during the Holocene. There seems to be three major genetic lineages in P. pipistrellus that might represent 2-3 distinct species: one throughout Europe and Asia, one in North Africa, and the other in Corsica and Sicily, which is sister to the North African part. Two subspecies recognized.

Due to the separation of P. pipistrellus and P. pygmaeus ( Barratt et al. 1997 ; Dietz et al. 2009 ) and the lack of any characters allowing for species identification, the only previous record ( Uhrin et al. 1996 ) has to be assigned to P . pipistrellus sensu lato (Sachanowicz et al. 2006). Although scarcely known until 2003 (21 species and unidentified representatives of three species complexes), the bat fauna of Albania is presently adequately surveyed with 32 recorded species. Our research has confirmed that Albania is one of the European countries with the highest bat species richness. In the geographic Balkans, where 35 bat species are known ( Dietz and Kiefer 2014 ), a greater or equal number of species has only been recorded in Bulgaria with 33 species if an acoustic record of Myotis dasycneme (Boie, 1825) over the Danube river is included ( Benda et al. 2003 ; Mayer et al. 2007 ; Niermann et al. 2007 ) and continental Greece with 32 species ( Hanák et al. 2001 ; Mayer et al. 2007 ). For two of the rarest European bats, R. mehelyi and N. lasiopterus , but also for M. brandtii , Pl. kolombatovici and B. barbastellus , we greatly extended their known geographic ranges in the south of Europe ( Dietz et al. 2009 ). The previous record of M. nattereri in Albania ( Chytil and Vlašín 1994 ) was most probably of this species, which is the only representative of the M. nattereri complex confirmed in the Balkans so far ( Salicini et al. 2013 ). Of the two Balkan species not recorded in Albania , Eptesicus nilssonii is only known from single localities in Bulgaria ( Benda et al. 2003 ) and Croatia ( Pavlinić and Tvrtković 2003 ) whereas the known range of M. aurascens (sensu Mayer et al. 2007 ) covers only a small area of northeast Bulgaria and extends to Romania , Ukraine and Russia ( Dietz and Kiefer 2014 ).