An in-depth study using GPS-sensors placed on northern bald ibises may finally explain why birds fly in V-formation.
Scientists found each ibis flew at a 45-degree angle positioned an average of four feet behind the bird in front of it. This position is precisely the place to catch the rising air, or “upwash,” from the flapping wings of the bird in front, according to the study published in Nature Thursday.
"Downwash is bad," explained lead researcher Dr. Steven Portugal. "Birds don't want to be in another bird's downwash as it's pushing them down."
"They're seemingly very aware of where the other birds are in the flock and they put themselves in the best possible position,” he tells the BBC.
Just as precise as their positioning, they also timed wing beats precisely so they continuously catch the upwash – their wingtips tracing the same path in the air as the bird in front.
"This can give a bit of a free ride for the bird that's following," he said. "So the other bird wants to put its own wingtip in the upwash from the bird in front."
These results "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."
“What these birds are able to do is amazing," Portugal said. "They're able to sense what's going on from the bird in front, where this good air is coming from and how to position themselves perfectly in it. So from a sensory point of view, it's really incredible."