Guardian bird watches over the flock
Birds living in the wild regularly face the challenge of looking for food, while at the same time keeping a watchful eye out for predators.
British researchers report that small groups of Pied Babblers use a sentinel to watch for predators, allowing the other Pied Babblers to focus on searching for food. The sentinel sings a "watchman's song" to tell other members of its group they are free to forage for food.
The scientists speculate that the unselfish, cooperative behavior of the sentry is rewarded by the improved survival of the group.