Journal article

What Makes Vocalisation Frequency an Unreliable Signal of Body Size in Birds? A Study on Black Swans

Rakhee Patel, Raoul A Mulder, Goncalo C Cardoso

ETHOLOGY | WILEY | Published : 2010


In many animal species, the frequency (pitch) of vocalisations correlates negatively with body size and may thus signal competitive ability. However, this relationship is absent in other species. Understanding why this difference exists across species may help to explain some of the diversity of vocal communication systems. We assessed whether vocalisation frequency signals body size in black swans (Cygnus atratus), and how this is affected by (i) variation in frequency within individuals and (ii) size variation across individuals. Frequency was correlated with body size and mass, with slopes close to the allometry expected if the birds were maximising sound radiation, but the explained vari..

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University of Melbourne Researchers


Awarded by Australian Research Council

Awarded by University of Melbourne

Funding Acknowledgements

We thank Patrick-Jean Guay, John Baumgartner, Sally Sherwen and numerous volunteers for help with fieldwork, and the staff of Parks Victoria at Albert Park for permission to work in the park. This research was supported by a Discovery grant from the Australian Research Council (DP0558607) and an early career researcher grant from the University of Melbourne (ECR600453).