Birds guard each other

BRISTOL, England, April 19 (UPI) -- British researchers say some birds serve as guards to keep their foraging colleagues safe while looking for food.

The findings, published in the journal Current Biology, suggest that the distinctive watchman's song of the pied babblers is a rare example of cooperative behavior in the animal world, the University of Bristol said in a release.

"The unselfish behavior of the sentry was rewarded further down the line by the improved survival of individuals, which in turn leads to a larger group size," researcher Andy Radford said in a statement. "This increases the sentinel's chances of survival when the group is under attack or having to repel rivals from the territory."

Radford said when a sentry bird was present the group was able to spread out more and spend more time in the open, allowing the group to catch bigger and better prey.