Flights of fear: A mechanical wing whistle sounds the alarm in a flocking bird

Mae Hingee, Robert D. Magrath

    Research output: Contribution to journalArticlepeer-review

    66 Citations (Scopus)


    Animals often form groups to increase collective vigilance and allow early detection of predators, but this benefit of sociality relies on rapid transfer of information. Among birds, alarm calls are not present in all species, while other proposed mechanisms of information transfer are inefficient. We tested whether wing sounds can encode reliable information on danger. Individuals taking off in alarm fly more quickly or ascend more steeply, so may produce different sounds in alarmed than in routine flight, which then act as reliable cues of alarm, or honest 'index' signals in which a signal's meaning is associated with its method of production. We show that crested pigeons, Ocyphaps lophotes, which have modified flight feathers, produce distinct wing 'whistles' in alarmed flight, and that individuals take off in alarm only after playback of alarmed whistles. Furthermore, amplitude-manipulated playbacks showed that response depends on whistle structure, such as tempo, not simply amplitude. We believe this is the first demonstration that flight noise can send information about alarm, and suggest that take-off noise could provide a cue of alarm in many flocking species, with feather modification evolving specifically to signal alarm in some. Similar reliable cues or index signals could occur in other animals.

    Original languageEnglish
    Pages (from-to)4173-4179
    Number of pages7
    JournalProceedings of the Royal Society B: Biological Sciences
    Issue number1676
    Publication statusPublished - 7 Dec 2009


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