Fork-tailed drongos use deceptive mimicked alarm calls to steal food.
Despite the prevalence of vocal mimicry in animals, few functions for this behaviour have been shown. I propose a novel hypothesis that false mimicked alarm calls could be used deceptively to scare other species and steal their food. Studies have previously suggested that animals use their own species-specific alarm calls to steal food. However none have shown conclusively that these false alarms are deceptive, or that mimicked alarm calls are used in this manner. Here, I show that wild fork-tailed drongos (Dicrurus adsimilis) make both drongo-specific and mimicked false alarm calls when watching target species handling food, in response to which targets flee to cover abandoning their food. The drongo-specific and mimicked calls made in false alarms were structurally indistinguishable from calls made during true alarms at predators by drongos and other species. Furthermore, I demonstrate by playback experiments that two of these species, meerkats (Suricata suricatta) and pied babblers (Turdoides bicolor), are deceived by both drongo-specific and mimicked false alarm calls. These results provide the first conclusive evidence that false alarm calls are deceptive and demonstrate a novel function for vocal mimicry. This work also provides valuable insight into the benefits of deploying variable mimetic signals in deceptive communication.
Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. tpf24@cam.ac.uk
Tom
T
Flower
D000161:Acoustic Stimulation; D000818:Animals; D008192:Deception; D046093:Falconiformes / Q000502:physiology; D005502:Food; D046109:Passeriformes / Q000502:physiology*; D013018:Sound Spectrography; D013045:Species Specificity; D014828:Vocalization, Animal