The familiar “V” formation birds assume when in flight, engrained in our shared cultural cognizance by the 1992 Walt Disney movie “The Mighty Ducks,” has long baffled scientists who, aside from theories, had little evidence to explain exactly why it is birds benefit from the distinct aerial arrangement. Until now.
A new study published in the journal Nature and led by researchers from Royal Veterinary College in the UK sheds light on the age-old mystery surrounding birds' peculiar flight formation. Scientists have long understood that birds benefit from flying in a “V” – as birds flap their wings, they create a rolling vortex of air that makes the air off to the sides of them push upwards, allowing any bird that flies within these upwash zones to get a free lift – but this new research suggests birds actually know just how to use this phenomenon to their advantage. Like players on a football field assembling themselves for a play, birds are keenly aware of how the formation they take in the air benefits the flock as a whole. In the words of study author Steven Portugal, birds have a “remarkable awareness” of aerodynamics and how to use them to their advantage.
"The intricate mechanisms involved in V formation flight indicate remarkable awareness and ability of birds to respond to the wing path of nearby flock-mates,” Portugal said in a statement, according to Discovery. “Birds in V formation seem to have developed complex phasing strategies to cope with the dynamic wakes [turbulent air] produced by flapping wings."
Bird formations, called echelons, come in many forms. According to Scientific American, the “J” formation is actually more common than the “V” formation, but the V is probably the most widely recognizable. Other flight formations also occur.
To find out exactly why birds fly in a V, Portugal and his team attached sensors to the wings of northern ibises. Led by a small motor-driven aircraft vehicle, the flock took flight while researchers noted their every move. The data revealed that the birds flew just as scientists predicted: around one meter behind the bird in front of it and about a meter off to the side. They also found that the flock members swapped positions frequently and changed leaders.
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“[The results of the study] once again remind us that animals are much more complicated … than we often give them credit for," Kenny Breuer, a professor of engineering and ecology at Brown University who was not involved with the study, told USA Today. "They're reacting in very sophisticated ways to maintain these V formations."
Portugal said ornithologists always assumed birds learned how to fly in a V from adults. The birds Portugal and his team worked with, however, were all adults and learned to fly from a human (the birds were part of a conservation effort in Austria to reintroduce the endangered species into the wild).
Previous studies of birds in flight have shown that flocks that fly in a V actually conserve energy. According to a 2001 report on bird formations, when researchers from the French National Center for Scientific Research attached heart-rate monitors to a flock of pelicans, they found that birds at the back of the formation flapped less and had slower heart rates than those in the front.
"A trailing bird can fit outside the wake of the bird in front, sitting in a passage of rising air," Jeremy Rayner, a bird expert from the University of Leeds, told NPR in 2001. "When the air is rising, it can fly with slightly less energy. We know this works in aircrafts flying in a V-formation."