About the Authors

Eva Maria Luef

Affiliation Max Planck Institute for Ornithology, Humboldt Research Group: Comparative Gestural Signalling, Eberhard-Gwinner-Strasse, 82319, Seewiesen, Germany

Thomas Breuer

Affiliation Global Conservation Program, Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, New York, 10460, United States of America

Simone Pika

spika@orn.mpg.de

Affiliation Max Planck Institute for Ornithology, Humboldt Research Group: Comparative Gestural Signalling, Eberhard-Gwinner-Strasse, 82319, Seewiesen, Germany

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: EML SP. Performed the experiments: EML. Analyzed the data: EML TB SP. Contributed reagents/materials/analysis tools: EML SP. Wrote the paper: EML TB SP.