Fig S4. A
spectrographic view of a 10 minute song recording. A spectrographic view of
a 10 minute recording showing phrase sequences from songs of at least 3
different singers . The whales are appear to be singing the same song but
asynchronously. One of the singers is likely singing closer to the hydrophone
than the other two since the song units of that singer‘s song are clearer on
the spectrogram (with greater SNR). Such circumstances may make it easier for
observers to delineate the songs found in the recording if there is a regular
overlap of song units from different singers.