NEW YORK — The next time you see birds flying in a V, consider this: A new study in the journal Nature says they choreograph the flapping of their wings with exquisite precision to help them on their way.
That's what scientists concluded after tracking 14 northern bald ibises as they migrated between Austria and Italy. The birds were taught to follow an ultralight aircraft as part of a conservation program, and each one was equipped with a tiny GPS device to record its position and every wing flap.
An analysis of a seven-minute period showed that when the ibises flew in a V, they positioned themselves in just the right places to exploit the updraft in another bird's wake, which lets them conserve their energy.
They also appeared to time the flapping of their wings to take full advantage of that updraft, by making a wingtip follow the same undulating path through the air as the wingtip of the bird up ahead. It's like one car following another on a roller coaster.
And when one bird flew directly behind another instead, it appeared to adjust its flapping to reduce the effects of the wake's downdraft. So birds can either sense or predict the wake left by their flock mates and adjust their flapping accordingly - a remarkable ability, the researchers said.
- The Associated Press
The principal author of the Nature study, titled "Upwash Exploitation and Downwash Avoidance by Flap Phasing in Ibis Formation Flight," is Steven Portugal of the Royal Veterinary College. Other authors include Tatjana Hubel, Johannes Fritz, Stefanie Heese, Daniela Trobe, Bernhard Voelkl, Stephen Hailes, Alan Wilson and James Usherwood.