Fig. 5. Call parameters of Phyllostomus discolor in Experiment 2 (echolocation). (A) Histogram of the durations of the analysed calls. Median and quartiles are indicated by the vertical lines. (B) One example call of Bat 4 plotted as spectrogram (top), as oscillogram (bottom) and as amplitude spectrum (right). The amplitude spectrum was calculated from the section between the vertical lines in the time signal. (C–H) Spectral parameters. For analysis, we used the five calls with the highest signal-to-noise ratio per sequence and calculated the mean per sequence of every parameter. The means per sequence were then grouped, either per stimulus (i.e. the combinations of filter slope and noise backgrounds; the larger part of the panels, between –6.0 and +6.0 dB/octave; N=33–59 sequences per test stimulus, 766–1252 sequences per control stimulus) or per noise background (small right part of the panels, marked B; N=214–2694 sequences per background), and their second order mean ± s.e.m. was plotted. Note the different scales of the y-axes. Grey symbols, white-noise background; coloured symbols, pink-noise background. ^*P<0.05, ^**P<0.01, ^***P<0.001.