Birds that fly in v-formation use amazing tricks!
“Use what talents you have; the woods would have little music if no bird sang their song except those who sang best” - Reverand Oliver G Wilson.
How beautiful !! Birds fly in V-shape. What can be the reason? Everyone wants to complete his task in an optimized way. Similarly, birds take the benefits of it after optimizing aerodynamic drag force with the help of skein formation. Mainly migratory birds takes this advantage because they have to fly thousands of kilometers from cold place to suitable warm place and one flight journey can be maximum of 16 hours. So in this difficult time, they take the benefits of other group members(‘strength of unity’). So they form vic-formation and cooperate with each other for switching the position as the bird in front experience a maximum drag force and minimum by last ones. Nowadays benefits of this Vic formation is also used by humans. Eg: Military flight- as fuel consumption reduced and almost 20% fuel is saved because of reduced drag surfing and taking advantage of another aircraft.
Here is the standard explanation for V -formation: It was an interesting study, which confirmed that birds benefit from flying in V shape. In 2001, Henri Weimerskirch did an experiment, when he fitted pelicans with heart rate monitors. He finds that birds at the back of the V had a slower heart rate than those in the front, and flapped less often. But it didn’t tell why or how they do so. But Steven Portugal wanted to know about that, so he takes help of Johannes Fritz who is working for an American conservation organization that is trying to save northern bald ibis (a species of birds-a critically endangered species). They planned to follow the flock of ibis birds by the support team as they stop at fixed places along the route. That gave Portugal plenty of chances to fit the birds with loggers, record every flap of their wings for long stretches, and retrieve the data a few hours later. After all efforts recording gave the same result as predicted by theoretical simulation: birds fly around a meter behind the bird on the front, and another meter off to the side. But flying in a V isn’t just about staying at the right place but it’s also about flapping at the right time. Here the two important term plays an important role
- Downwash: When a bird flaps its wings, a vortex of air directly behind it is pushed downward called downwash.
- Upwash: The air further back and to the sides responds by pushing up called upwash.
So here birds take the advantage of upwash created by the bird in front because any bird situated in upwash of another bird has to spend less energy to stay aloft since they already pushed upward. Sometimes bird caught into a downwash of a front bird while switching the position. If that happens, they change their flapping so that they’re doing the opposite of what the bird in front does.
It’s interesting, right? But how do they manage? No one knows. They might be using their wing feathers to sense the airflow around them. Or they could just be relying on simple positive feedback. “They’re flying around, they hit a spot that feels good, and they think: Oh, hey, if I flap like this, it’s easier,” says Portugal. Whatever it is, this isn’t a skill they are born with. It took time for them to fly in V and they learned from each other. Eventually, Nature is really interesting but the thing is we need to feel it and start observing what is happening around us.Written by Sagar Ror on 20 Oct 2020