Spectrograms of different vocal categories of the adult male Asian koel.

Two consecutive type 1 cooee calls (A), two consecutive type 2 cooee calls (B), two consecutive type 1 coegh calls (C), two connective type 2 coegh calls (D), a bout of wurroo calls (E), two consecutive coe calls (F). Spectrograms were constructed in Praat using the Fast Fourier Transform method (FFT), Gaussian window shape, window length of 0.012 s, frequency view range of 700–24000 Hz, pitch floor of 75–700 Hz, dynamic range of 70 dB, intensity range of 30–100 dB, 0.5 s zooming level.