Fig S1. Estimating number of singers from a spectrogram

Fig S1. Spectrograms of overlapping singers. The upper panel shows spectrograms of singers overlapping their songs in time. The lower panel shows the same spectrograms where each song unit, used in the overlapping estimate, is colored and labelled with a number representing each whale in the overlapping event. Two aligned, overlapping events are shown in each spectrogram. The vertical gray line shows where an overlap event occurred between the colored signals in time. Each spectrogram is independent from the other and were from various times of the study period. The colors and numbers are only to discriminate between singers during an overlapping event. In the first spectrograms where two singers overlap, a sub-phrase is identified from one whale. The sub-phrase included two song units that were labelled nr. 1 and identified with red color.