These Migrating Birds Take Turns at the Hard Work of Windbreaking
Posted by Richard Conniff on February 1, 2015
When flying in formation, the lead bird does the aerodynamic heavy lifting, and everybody else benefits by following in the aerodynamically sheltered path of another bird. So why does the lead bird do it? And do they take turns? A new study of Northern Bald Ibises tests that question with multiple observations of migrating flocks.
They find that these birds travel in stable flocks, often including many related individuals. So they know each other and have ample motive for reciprocation. The result is that they do indeed take turns, following certain character patterns of shifting position. The authors conclude: “The V-formation flight of Northern bald ibis does not only provide a convincing example for reciprocal altruism in animals, but it also delivers hints for the conditions that might have favored its evolution.”
Check out the full article in PNAS here.