First record of a larger hibernaculum of the Soprano pipistrelles Pipistreiius pygmaeus (Leach, 1825) in Slovenia PRVA NAJDBA VEČJEGA PREZIMOVALIŠČA DROBNIH NETOPIRJEV PIPISTRELLUS PYGMAEUS (LEACH, 1825) V SLOVENIJI Alenka PETRINJAK, Gosposvetska ulica 15, SI-4000 Kranj; e-mail: alenka.petrinjak@gmail.com In December 2009, the Slovenian Association for Bat Research and Conservation received a call about bats hiding in an unused ventilation duct of the family house in the village of Crngrob near Škofja Loka in NW Slovenia (exact address: Crngrob 13, coordinates from Atlas okolja ARSO: GKY:446824, GKX: 117232). More than 10 bats were flying around the house. On 24th December 2009, we checked which bats were roosting there (the highest daily air temperature: 10.8°C, Košir 2011). We found a dense cluster of numerous hibernating Pipistrelle bats (Pipistreiius sp.). We removed one female and identified it as Soprano pipistrelle (PipistreHus pygmaeus, AB=30.2 mm). A week later, on 30th December, we checked the roost once more (the highest daily air temperature: 9.6°C, Košir 2011). On this occasion, we were able to count 62 individuals, but we estimated their number to be higher (probably about 100 animals), due to individuals hiding behind the visible ones. We measured 4 females (female1: AB=30.6 mm D5=39.4 mm; female2: AB=31.8 mm D5=42.1 mm; female3: AB=31.3 mm D5=39.0 mm; female4: AB= 31.4 mm D5=40.4mm) and 2 males (male1: AB=30.2 mm D5=38.2 mm; male2: AB=29.1 mm D5=37.9 mm) and determined (according to Dietz et al. 2007) all of them as Soprano pipistrelles. Despite that it could be possible that the colony contained also individuals of Common pipistrelle (PipistreHus pipistrelus), as Kanuch et al. (2010) report about hibernation colony of Common pipistrelle mixed with few individuals of Soprano pipistrelles. The Soprano pipistrelle is a generally distributed species in Slovenia (Presetnik et al. 2001, 2009). Most data were collected with the use of ultrasound detectors, but also with mistneting and through accidental findings. The findings of species roosts are very rare. Our finding of hibernation roost of Soprano pipistrelles at Crngorb confirms that the species has group hibernacula in Slovenia. Literature Dietz C., Helversen O., Nill D. (2007): Handbuch der Fledermäuse Europas und Nordwestafrikas: Biologie, Kennzeichen, Gefährdung. Cosmos Verlag, Stuttgart, 399 pp. Kanuch P., Fornöskova A., Bartonička, T. Bryja J., Rehak Z. (2010): Do two cryptic pipistrelle bat species differ in their autumn and winter roosting strategies within the range of sympatry?. Folia Zoologica, Brno, Institute of Vertebrate Biology AS CR 59(2): 102-107. Košir D. (2011): The highest daily air temperature on 24th December 2009 and 30th December 2009. Amateur meteorological station Trnje, Škofja Loka, weather station Davis Vantage Pro2. Presetnik P. (2009): Drobni netopir - Pipistreiius pygmaeus (Leach, 1825). In: Presetnik P., Koselj K., Zagmajster M. (Eds.), Atlas netopirjev (Chiroptera) Slovenije, Atlas of bats (Chiroptera) of Slovenia. Centre for Cartography of Fauna and Flora, Miklavž na Dravskem polju, pp. 82-83. Presetnik P., Koselj K., Zagmajster M. (2001): First record of PipistreHus pygmaeus (Leach, 1825) in Slovenia. Myotis 39: 29-32. Slika 1. Gruča prezimujočih malih netopirjev, verjetno večinoma drobnih netopirjev (Pipistre/lus pygmaeus), v zračniku hiše v Crngrobu pri Škofji Loki v SZ Sloveniji. Figure 1. The cluster of hibernating pipistrelles, probably mostly Soprano pipistrelles (Pipistrellus pygmaeus), in a ventilation duct of the family house at Crngrob near Škofja Loka in NW Slovenia.