Many birds are well known to relay distress calls to other members of their immediate population when threats appear. One species of bird native to Africa, the pied babbler, takes this behavior a step further. The birds forage and hunt in groups of six or seven, only one of those members does nothing but stand lookout. That bird spends its time scanning the area for predators and singing a song of all’s well. The other birds rely on the song in order to focus their efforts on finding food.
The behavior is more cooperative and altruistic than the way a bird like the robin finds its food, which often hunts in large groups for safety in numbers. A small group hunting that way would have to spend a disproportionate amount of time looking up and listening for trouble. The pied babbler lookout allows the other birds in its group to let down their guard and concentrate on the hunt.
Although the guard bird doesn’t benefit directly during a particular foraging session, the researchers think the behavior has evolved because of the advantages it confers on the group as a whole.