Shankar Vedantam
The Encyclopaedia Britannica notes that antbirds—tropical birds often found in the Amazon chasing columns of swarming ants—“have loud, usually unmusical voices that may be heard in echo duets”.

Research to be published in the journal Current Biology in April suggests a possible explanation for the cacophonous duets: female antbirds, researchers have found, “jam” the calls of their mates to other females by singing over the male voices. In response to being jammed, the males then change their tune.

Researchers Joseph A. Tobias and Nathalie Seddon of the University of Oxford said this was the first example of behaviour involving jamming, and jamming avoidance, ever seen in nature.

“In human terms, signal jamming is most commonly associated with attempts to scramble information in radio, radar, or cell phone signals,” Tobias said in a statement. “The females in our study try to do a similar thing with the songs of their partner, but the overall situation is more analogous to a wife continually interrupting her husband to stop him from flirting with a single woman.”

Bird duets, the researchers conclude, can tell complex stories about conflict and cooperation within a species. By recording the birds and playing back their duets, the researchers found that there were times when male and female birds would sing in harmony—often when they were fending off common rivals. But when the bond between the birds was threatened by a single female, the birds resorted to cacophonous jamming and jamming defense calls.

If such techniques were part of the evolutionary history of humans, the researchers noted, “our results may help to explain the first steps towards complex, coordinated group signals in humans, which themselves are the likely forerunners to modern music.” LATWP