When migrating in their signature V-shaped formation, birds diffuse a particular "social dilemma" by rotating the leader of the flock.

According to BBC News, an international team of scientists published a study in the journal Proceedings of the National Academy of Sciences on the northern bald ibis. Rotation of leadership over the flock was also revealed to be a method to conserve energy, as leading can be taxing.

"These birds go from Austria to Italy - a journey of 1,500km," study lead author Bernhard Voelkl, a zoologist at the University of Oxford, told BBC News. "Mortality is really high - 30 percent of juveniles don't survive the first migration."

Leading the flock into migration was previously seen as a selfish act, in one bird is draining its energy faster for the betterment of the group. But the new study proves these migrating flocks are thinking of the group's collective energy.

"Our study shows that the 'building blocks' of reciprocal cooperative behavior can be very simple: ibis often travel in pairs, with one bird leading and a 'wingman' benefiting by following in the leader's updraft," Voelkl said in a press release. "We found that in these pairs individuals take turns, precisely matching the amount of time they spend in the energy-sapping lead position and the energy-saving following position.

"The checking that went on within these pairs was sufficient on its own to prevent any freeloaders hitching a free ride within a v-formation without leading," he said. "In fact, surprisingly, we found no evidence of 'cheating' of any kind within these flocks with the level of cooperation, with individuals benefiting from following 32 percent of the time, significantly higher than expected."