Sydney Morning Herald:
Birds of a feather may flock together, but why they fly together in V formations has never been known for certain. Now, with the help of 14 northern bald ibises fitted with lightweight sensors on a 1000-kilometre migration from Austria to Tuscany, researchers are suggesting that the explanation is one that was long suspected but never proved: the formation helps the birds conserve energy.
Reporting in the journal Nature, the scientists write that the ibises positioned themselves in spots which were aerodynamically optimal, allowing them to take advantage of swirls of upward-moving air generated by the wings of the bird ahead. The lead bird gets no lift advantage; the ibises regularly switched leaders.