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..View full abstract
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Awarded by Australian Research Council
Awarded by University of Melbourne
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).