Fig. 2

Distribution of northern bat passes recorded by ultrasound during the night across the whole season at the main site in Frafjord (n=10 489 minutes, late April to mid-October). The lower dashed line represents sunset, the upper represents sunrise and the central represents the sun at its lowest angle. Note that many points are superimposed. From the last days of September to October ultrasound recordings were only made in the first half of the night