Fig. 1

Measured acoustic variables in the discomfort sonic calls of the northern birch mice Sicista betulina. Spectrogram (right) and power spectrum (left). Designations: duration—call duration; f0_max—the maximum fundamental frequency; f0_min—the minimum fundamental frequency; f0_beg—the start fundamental frequency; f0_end—the end fundamental frequency; f_peak—the frequency of maximum amplitude; q₂₅, q₅₀, q₇₅—lower, medium and upper quartiles; bandwidth—the bandwidth of the f_peak at the distance of 10 dB from the maximum. The spectrogram was created with Hamming window; 48 kHz sampling rate; FFT 1024 points; frame 50%; and overlap 93.75%