a b s t r a c tClimatic conditions such as temperature and seasonality are becoming increasingly harsh towards the latitudinal extreme of the distribution and may limit the occurrence of mammals through decreased food availability or accessibility. For nocturnal bats increasing day length in summer may also limit the range latitudinally.We investigated the effect of long term mean temperature, precipitation, altitude, water affinity, terrestrial habitat, and topography on the summer distribution of the soprano pipistrelle Pipistrellus pygmaeus at its northern limit in western Norway (62 • N, 06 E) in a fiord landscape. We recorded presence/absence of the species in 138 sites by means of ultrasound detectors (and an acoustic lure).A binary logistic regression analysis showed that temperature is significant in predicting occurrence of soprano pipistrelles, with no animals in areas of less than 13 • C (long term mean July temperature). Further, the model suggests that the species prefers areas where steep mountains to the north shade out the sun before sunset and after sunrise. Here soprano pipistrelles can start hunting up to 2 h earlier than in a flat landscape, thus spending more time on energy consumption.

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Most bat species show plasticity in their choice of habitat and landscape. This study focuses on the distribution and activity of bats along the hillsides and onto the shores of a low salinity marine Norwegian fiord at 62°N. Ultrasound was recorded using D500 detectors in June and July at 42 different sites from the shoreline and up the hillsides to around 200 m. Detectors were placed in well-preserved woodlands. OnlyPipistrellussp., northern batsEptesicus nilssoniiand bats of theMyotisgenus were common. There was a clear non-linear spatial distribution pattern along these slopes, with a pronounced increase in the number of recorded bats at short distances from the shore. On all six nights, the detector closest to the shore had the highest number of recorded bats. A pattern was also seen in bat distribution over time.Pipistrellussp., northern bats andMyotisspecies all had a peak near the shore during the darkest part of the night, which is around 01.35 h in mid-summer at this latitude. At greater distances,Pipistrellussp. and northern bats had a peak around 40 minutes to one hour before the darkest part of the night, respectively. Here,Myotisspp. peaked about an hour after 01.35.