The chirp of chickadees can convey complex information about predators, warning flock mates of danger, shows a study to be published on Friday's issue of journal Science.
The little black-capped songbird, which is common across much of the United States and Canada, uses subtle variations of its characteristic "chick-a-dee-dee" call to pass detailed information such as what and where the predator is and how dangerous it is.
For example, the more "dee" notes at the end of a call, the more dangerous the predator, biology Ph.D. student Christopher Templeton of the University of Washington and his colleges have found. Other acoustic techniques include the spacing and timing of notes.
The chickadee call can also bring in the birds to mount a coordinated defense to drive away the predator.
In the study, chickadee songs were recorded, analyzed by situation and on acoustic instruments, and played back to the birds to see how they reacted.