Figure 1

Example spectrogram of a cao vit gibbon duet, showing the male (staccato, multi-modulated and coda) and female (great call) contributions. Males also have a boom phrase, not shown here. Audio was recorded using an AudioMoth and the spectrogram was visualised using Raven Pro (with settings as given in the main text). An example bounding box annotation around the male multi-modulated phrase is also shown (in blue).