FIGURE 4. Comparative spectrograms of a call of Dryophytes andersonii, all drawn with Hanning window function, showing the effect of different FFT resolution on the graphic representation of calls. Each spectrogram shows the identical 300 ms section of a recording. Note that with higher FFT settings, the spectral detail of the call representation increases. At lower FFT settings, the temporal pattern of the call is more clearly recognizable. Call recording taken from Elliot et al. (2009). Graphics produced with the R package Seewave (Sueur et al. 2008a).