Birds fly in 'V' formation to save energy, study finds (Update)

Jan 15, 2014 by Malcolm Ritter
In this undated photo made available by journal Nature on Jan. 15, 2015, northern bald ibises (Geronticus eremita) fly in formation. A new study released Wednesday, Jan. 15, 2014 says the birds choreograph the flapping of their wings, getting a boost from an updraft of air in the wake of the flapping wings by flying behind the first bird and off to the side. When a flock of birds take advantage of these aerodynamics, they form a V. (AP Photo/Markus Unsöld)

The next time you see birds flying in a V, consider this: A new study says they choreograph the flapping of their wings with exquisite precision to help them on their way.

That's what scientists concluded after tracking a group of large black birds—each equipped with a tiny GPS device—that had been trained to follow an ultralight aircraft. One expert in animal flight said just gathering the data, which included every wing flap, was a remarkable accomplishment.

Scientists have long theorized that many birds like these rare northern bald ibises adopt a V formation for aerodynamic reasons.

When a bird flies, it leaves a wake. The idea is that another bird can get a boost from an updraft of air in that wake by flying behind the first bird and off to the side. When a bunch of birds use this trick, they form a V.

It's been difficult to study this in the wild, but researchers from the University of London's Royal Veterinary College and elsewhere met that challenge by partnering with a conservation program that is trying to reintroduce the endangered wading bird in Europe.

For about a decade, the program has hand-reared ibises from zoos and taught them their migration route by leading the way with a piloted ultralight craft. Normally, the leader of a V-formation would be a parent bird.

In this undated photo made available by journal Nature on Jan. 15, 2015, northern bald ibises (Geronticus eremita) fly in formation next to a microlight aircraft. A new study released Wednesday, Jan. 15, 2014 says the birds choreograph the flapping of their wings, getting a boost from an updraft of air in the wake of the flapping wings by flying behind the first bird and off to the side. When a flock of birds take advantage of these aerodynamics, they form a V. (AP Photo/Markus Unsöld)

With the program's help, the researchers tracked 14 juvenile ibises as they migrated between Austria and Italy.

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.

A graphic showing how groups of birds coordinate in flight to perfect their migration techniques

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.

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The scientists reported their results online Wednesday in the journal Nature. It's the first experimental evidence that birds can adjust their flapping to take advantage of the wake, Florian Muijres and Michael Dickinson of the University of Washington wrote in an accompanying commentary.

Kenny Breuer of Brown University, who did not participate in the work, said collecting the study data from the free-flying birds was "quite an astonishing feat."

In this undated photo made available by journal Nature on Jan. 15, 2015, a northern bald ibis (Geronticus eremita) flies in Tuscany, Italy. A new study released Wednesday, Jan. 15, 2014 says the birds choreograph the flapping of their wings, getting a boost from an updraft of air in the wake of the flapping wings by flying behind the first bird and off to the side. When a flock of birds take advantage of these aerodynamics, they form a V. (AP Photo/Markus Unsöld)


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User comments : 13

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markheim
5 / 5 (3) Jan 15, 2014
This is really old news. It's because of reduced air drag. They even take turns sometimes!
Whydening Gyre
5 / 5 (1) Jan 15, 2014
Ya.. like 20 years, at least....
qquax
5 / 5 (1) Jan 15, 2014
It's such old news that V formation flight has even been proposed for civil aviation to save on fuel, as reported on this very site: http://phys.org/n...ion.html
PsycheOne
5 / 5 (3) Jan 15, 2014
I believe the "new" news is that each birds flaps its wings in phase with the bird in front. They either fly half a wave length or a full wave length behind and depending on which, they flap in synch or opposite.

The fact that a bird can figure this out would be astonishing to anyone who assumes they are not too smart. The fact that a group of birds who have never been taught by their parents to fly in formation figure out how to do fly in a V and synch their wings when flying behind a human in a light aircraft is even astonishing to me.
Iochroma
5 / 5 (1) Jan 15, 2014
The physics of this formation was taught to me 40 years ago in college; film of birds flying was analyzed to understand how the birds stayed in phase. What is so new that the journal Nature would publish it? The writer of this article failed to make it clear.
antigoracle
1 / 5 (3) Jan 15, 2014
Hmmm... I always thought, it was because the one behind did not want the one in front to crap in it's face.
Mimath224
not rated yet Jan 15, 2014
Didn't NASA also do considerable research into wingtip vortices etc?

I believe the "new" news is that each birds flaps its wings in phase with the bird in front. They either fly half a wave length or a full wave length behind and depending on which, they flap in synch or opposite.

The fact that a bird can figure this out would be astonishing to anyone who assumes they are not too smart. The fact that a group of birds who have never been taught by their parents to fly in formation figure out how to do fly in a V and synch their wings when flying behind a human in a light aircraft is even astonishing to me.

Is that really the case or do birds automatically drift into the v form due to the other flight vortex 'persuasions'?
kochevnik
not rated yet Jan 16, 2014
Birds do not fly in a V formation. They fly in a formation dictated by triangular numbers, so that the vortices fractally nest
AeroSR71
not rated yet Jan 16, 2014
I'm sure birds are genetically controlled when and how they decide to migrate. I suppose the V formation would have stood out as the most economically feasible mode of transportation.
Dug
1 / 5 (1) Jan 16, 2014
"It's the first experimental evidence that birds can adjust their flapping to take advantage of the wake, Florian Muijres and Michael Dickinson of the University of Washington wrote in an accompanying commentary." This is not an experiment - no variables were changed and the resultant changes recorded and compared. The "evidence" is only observed natural behavior. This was an observation, not an experiment. And as apparently we all know - it's far from a first observation of this phenomena - or explanation of the observed aerodynamic physics.
shavera
not rated yet Jan 16, 2014
The key to the article is the synchronization of wing flapping that facilitates the long-proposed aerodynamic efficiency. Ie, we've assumed it was more efficient, and this helps to provide additional evidence to support that assumption.
meBigGuy
not rated yet Jan 18, 2014
Have you ever wondered why one leg of the V is longer than the other?

We did an extensive study on that last year. We discovered that the longer leg had more birds.
Whydening Gyre
not rated yet Jan 19, 2014
Have you ever wondered why one leg of the V is longer than the other?

We did an extensive study on that last year. We discovered that the longer leg had more birds.

Which leg is longer? The right or left?