Fig. 4From: The influence of night length: Activity of the northern bat Eptesicus nilssonii under conditions of continuous light in midnight sun compared to a southern populationPercent recordings by hour and different recording techniques. Counts: visual counts (both exits and returns) at all roosts in Troms, Infrared: IR detection at two roosts in Troms, Troms: ultrasound recordings, Frafjord: ultrasound recordingsBack to article page