Figure 1. Sampling protocol of experimental trials carried out at 20 independent sites from July to September 2007.

At each site bat activity was recorded for 1 h at three distances from the radar antenna (10,20,30 m) using three automatic bat recording stations orientated perpendicular to the radar beam. A frequency division bat detector was positioned 20 m from the radar antenna to provide further information on bat foraging activity during this period.