Why Birds Fly In a V Formation:By Exploiting Aerodynamics And Conserving Energy, Migratory Birds Can Travel Obscene Distances
Migratory birds are a true feat of nature, from their precise navigation to their ability to migrate unseemly large distances. Why they fly in a V formation is another mystery that has amazed nature lovers for years. A new study published in Nature, however, claims to have figured it out: the formation is designed to exploit aerodynamics so as to conserve energy. It turns out that migratory birds coordinate their wing flaps with utmost dexterity, designed to reap the best energy savings for flying in formation.
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Earlier studies on V formation observed in migratory birds such as geese indicated that this formation helped them save energy. The earlier theoretical models also showed that the birds needed exceptionally precise coordination to benefit from the formation, and many scientists, according to Dr. Steven Portugal at the Royal Veterinary College in Hatfield, UK did not believe that birds could perform this amazing feat while flying.
For the birds to take maximum advantage of the V aerodynamics, they must be able to position their wings over the upward moving portion of the air vortex created by the bird in front. As the bird in front flaps its wings, the vortex moves up and down - meaning that the birds behind must be precise in their timing in order to maneuver and keep riding the "upwash," or lift. Scientists didn't expect this high level of precision from the birds, so they suggested alternative reasons for the formation. They had two hypotheses: first that the V formation helped the birds defend against predators, or, second, that the formation made it possible for the better navigators fly ahead.
The new study attempted to test the aerodynamics hypothesis. They designed instruments to record the Global Positioning System (GPS) location of the birds in sync with an accelerometer to count wingflaps. The GPS data could be recorded five times per second. In order to find a flock of free-flying, yet tame enough birds to track, Portugal's team turned to Dr. Johannes Fritz, who had been working on a conservation project with flocks of the northern bald ibsis. Fritz had trained the birds to follow human foster 'parents,' and together, the team was able to fixed data loggers to 14 young ibises in August of 2011.
After analyzing the resulting data, Portugal was surprised to learn that the birds' formation matched the theoretical aerodynamics prediction. In other words, the birds were seen flapping at the best time while positioning themselves in the best place, according to Portugal. Nonetheless, it was intriguing for the scientists to note that birds frequently shifted from optimal to less optimal positions - for apparently no reason, the birds would shift out of the energy-saving V formation.
The answer may come, according to behavioral ecologist Martin Wikelski of the Max Planck Institute for Ornithology in Radolfzell, Germany, with the application of better GPS technology that can measure both vertical and horizontal positions of birds.
Photo of migratory birds via Shutterstock.
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