Humpback whale (Megaptera novaeangliae) singers in Hawaii are attracted to playback of similar song (L).

The use of playback experiments to study humpback whale song was assessed. Singers clearly detected playback song while singing and with other singers in the distance. Singers approached or joined song similar to their own from as far as 800 m but did not do so for a different (foreign) song. In one compound trial, on the playback of different song, the singer moved away and continued singing; when the playback was changed to similar song, it stopped singing and joined the playback speaker. Song playback experiments on the breeding grounds are viable and may provide insight into song function.