Biplot (axes 1 and 2) from a principal components analysis of variables calculated from buzz and non-buzz (control) echolocation calls.

<p>The following variables were calculated for each sequence of four consecutive signals from the signal inter-pulse interval (IPI), signal duration (dur), signal SNR (SNR) and signal smoothness (smooth): IPIslope = slope from a regression on IPI, IPIint = intercept from a regression on IPI, IPImin = minimum IPI, IPImax = maximum IPI, IPIavg = average IPI, IPIsd = standard deviation of the IPI, IPIvar = variance of the IPI, IPIshannon = Shannon entropy of the IPI, SNRr = adjusted rsquared for the regression on the signal SNR, SNRmin = minimum SNR, SNRmax = maximum SNR, SNRavg = average SNR, SNRsd = standard deviation of the SNR, SNRvar = variance of the SNR, slopeavg = average slope, slopemin = minimum slope, slopesd = standard deviation of the slope, duravg = average call duration, dursd = standard deviation of the call duration, smoothavg = average of the smoothness parameter, smoothvar = variance of the smoothness parameter.</p> <p>(PDF)</p>