Douglas H. Cato
Maritime Operations Div., Mater. Res. Lab., Defence Sci. and Technol. Organisation, P.O. Box 44, Pyrmont, NSW, 2009, Australia
Songs of humpback whales have been recorded in Australian waters for more than 10 years, and show features that are broadly similar (though different in detail) to the complex and stereotyped songs observed in the northern hemisphere. Observations have been made along the migration paths that follow the east and west coasts of the continent. Recordings at similar times but separated by thousands of kilometers along a particular coast are similar, but the song off the east coast does not appear to be related to that off the west coast. Both the characteristics of the sounds and the song pattern have changed progressively, but the rate of change has varied substantially from year to year. On the east coast the song has been observed to degenerate from its usual complex pattern to one with little structure, during a year of rapid change, and then return with time to its more usual form.