Figure 4.

Sonar sound groups under varying conditions. (A) One trial plotted in 3D from the Lake Artemesia field site. The bat's flight path is shown in blue, and timing of the vocalizations with blue dots. Black dots highlight vocalizations in a 4 call sound group, calls marked in red are 2-call sound groups (sonar call doublets). The microphone array is shown in black. (B) Time vs. pulse interval for the trial shown in (A). As in (A), P.I.'s marked with black are 4 call sound groups, and those with red dots are sonar call doublets. (C) Time vs. pulse interval for the recordings of commuting bats at Rockville, MD. Only one sequence of vocalizations (shown in black squares) qualified as a sound group by our definition. The low (around 120 ms) and high (around 240 ms) PIs correspond to emitting a call per wing beat or only for every second wingbeat respectively. Sometimes the bats skipped two wingbeats and PI became even longer, around 350 ms. (D) Number of sound groups uttered per trial for the commuting bats at Rockville, MD; and the hunting bats of Lake Artemesia, MD. (E) Average number of sound groups per trial in the four laboratory flight experiments (clutter, nethole, mantis, open room). Green errorbars denote the standard error, blue the standard deviation.