Claremore Daily Progress

Community News Network

January 21, 2014

Why birds fly in a V formation

Anyone watching the autumn sky knows that migrating birds fly in a V formation, but scientists have long debated why. A new study of ibises finds that these big-winged birds carefully position their wingtips and sync their flapping, presumably to catch the preceding bird's updraft - and save energy during flight.

There are two reasons birds might fly in a V formation: It may make flight easier, or they're simply following the leader. Squadrons of planes can save fuel by flying in a V formation, and many scientists suspect that migrating birds do the same. Models that treated flapping birds like fixed-wing airplanes estimate that they save energy by drafting off each other, but currents created by airplanes are far more stable than the oscillating eddies coming off of a bird. "Air gets pretty darn wiggy behind a flapping wing," says James Usherwood, a locomotor biomechanist at the Royal Veterinary College at the University of London in Hatfield, where the research took place.

The study, published online Wednesday in Nature, took advantage of an existing project to reintroduce endangered northern bald ibises (Geronticus eremita) to Europe. Scientists used a microlight plane to show hand-raised birds their ancestral migration route from Austria to Italy. A flock of 14 juveniles carried data loggers specially built by Usherwood and his lab. The device's GPS determined each bird's flight position to within 30 cm, and an accelerometer showed the timing of the wing flaps.

Just as aerodynamic estimates would predict, the birds positioned themselves to fly just behind and to the side of the bird in front, timing their wing beats to catch the uplifting eddies. When a bird flew directly behind another, the timing of the flapping reversed so that it could minimize the effects of the downdraft coming off the back of the bird's body. "We didn't think this was possible," Usherwood says, considering that the feat requires careful flight and incredible awareness of one's neighbors. "Perhaps these big V formation birds can be thought of quite like an airplane with wings that go up and down."

The findings likely apply to other long-winged birds, such as pelicans, storks, and geese, Usherwood says. Smaller birds create more complex wakes that would make drafting too difficult. The researchers did not attempt to calculate the bird's energy savings because the necessary physiological measurements would be too invasive for an endangered species. Previous studies estimate that birds can use 20 percent to 30 percent less energy while flying in a V.

"From a behavioral perspective it's really a breakthrough," says David Lentink, a mechanical engineer at Stanford University in Palo Alto, California, who was not involved in the work. "Showing that birds care about syncing their wing beats is definitely an important insight that we didn't have before." To definitively say that the birds are drafting off each other, however, the exact location of the eddies and the areas of downdraft would need to be measured on ibises, which would require flying them in a wind tunnel - a far more intrusive process than simply carrying a data logger.

Scientists do not know how the birds find that aerodynamic sweet spot, but they suspect that the animals align themselves either by sight or by sensing air currents through their feathers. Alternatively, they may move around until they find the location with the least resistance. In future studies, the researchers will switch to more common birds, such as pigeons or geese. They plan to investigate how the animals decide who sets the course and the pace, and whether a mistake made by the leader can ripple through the rest of the flock to cause traffic jams.

"It's a pretty impressive piece of work as it is, but it does suggest that there's a lot more to learn," says Ty Hedrick, a biologist at the University of North Carolina, Chapel Hill, who studies flight aerodynamics in birds and insects. However they do it, he says, "birds are awfully good hang-glider pilots."

 

1
Text Only
Community News Network
  • Screen Shot 2014-04-16 at 12.51.22 PM.png VIDEO: Toddler climbs into vending machine

    A child is safe after climbing into and getting stuck inside a claw crane machine at a Lincoln, Neb., bowling alley Monday.

    April 16, 2014 1 Photo

  • Victimized by the 'marriage penalty'

    In a few short months, I'll pass the milestone that every little girl dreams of: the day she swears - before family and God, in sickness and in health, all in the name of love - that she's willing to pay a much higher tax rate.

    April 15, 2014

  • Allergies are the real midlife crisis

    One of the biggest mysteries is why the disease comes and goes, and then comes and goes again. People tend to experience intense allergies between the ages of 5 and 16, then get a couple of decades off before the symptoms return in the 30s, only to diminish around retirement age.

    April 15, 2014

  • treadmill-very-fast.jpg Tax deduction for a gym membership?

    April marks another tax season when millions of Americans will deduct expenses related to home ownership, children and education from their annual tax bill. These deductions exist because of their perceived value to society; they encourage behaviors that keep the wheels of the economy turning. So why shouldn't the tax code be revised to reward preventive health?

    April 15, 2014 1 Photo

  • Google acquires drone maker Titan Aerospace to spread Internet

    Google is adding drones to its fleets of robots and driverless cars.
    The Internet search company said it acquired Titan Aerospace, the maker of high-altitude, solar-powered satellites that provides customer access to data services around the world. Terms of the deal weren't disclosed.

    April 14, 2014

  • E-Cigarettes target youth with festivals, lawmakers say

    The findings, in a survey released Monday by members of Congress, should prod U.S. regulators to curb the industry, the lawmakers said. While e-cigarettes currently are unregulated, the Food and Drug Administration is working on a plan that would extend its tobacco oversight to the products.

    April 14, 2014

  • Why Facebook is getting into the banking game

    Who would want to use Facebook as a bank? That's the question that immediately arises from news that the social network intends to get into the electronic money business.

    April 14, 2014

  • Screen shot 2014-04-11 at 4.49.09 PM.png Train, entertain your pets with these 3 smartphone apps

    While they may not have thumbs to use the phone, pets can benefit from smartphone apps designed specifically for them.

    April 11, 2014 1 Photo

  • Stepping forward: The real Colbert

    Letterman changed the late-night TV game between his run on NBC's "Late Night" and starting the "Late Show" franchise in 1993. And while it's tough to replace a pop-culture icon, Colbert, in terms of pedigree and sense of humor, makes the most sense.

    April 11, 2014

  • Millions of Android phones, tablets vulnerable to Heartbleed bug

    Millions of smartphones and tablets running Google's Android operating system have the Heartbleed software bug, in a sign of how broadly the flaw extends beyond the Web and into consumer devices.

    April 11, 2014