You can look up to the skies and you see these really charismatic V-Formation flocks and people go “Why are they flying like that? How are they flying like that?” And we really wanted to try and answer that question.
So we were able to work with this pioneering conservation organization called The Waldrapp Team and what they’re doing is they’re reintroducing the critically endangered Northern Bald Ibis into its historical range in Europe. What that enables us to do is to work with their birds who are undertaking actual migratory flight to begin studying these aerodynamic interactions between the individuals and the flock.
Though what happens is when the birds are hatched they’re imprinted immediately onto these human foster parents and the human foster parents spend every waking moment of every day with these birds and they become completely imprinted; they spend all their time together. As the birds get older they’re told to fly behind a Microlight, which the human foster parent sits in and calls these birds to follow. What that enables us to do is to use our technology that we’ve developed in our lab: these little loggers here. They don’t look like much but what they are is amazingly powerful tools for understanding how animals move.
What we do is we put the loggers on the birds, these birds take off, they follow this Microlight, they undertake a portion of their migratory flight, they then come back down to earth, and we take the loggers off and start looking at the data that’s come off them.
The first interesting result is that the birds are positioning themselves in aerodynamically optimal positions. So they’re seemingly very aware of where the other birds are in the flock and they put themselves in the best possible position.
So what happens when a bird is flying forward is behind most of the bird you get ‘downwash,’ but off the wing tips you get this beneficial ‘upwash’ coming off which gives you a little extra lift – it can give you a bit of a free ride for the bird that’s following. So what the other bird wants to do is to put his wingtip in the upwash of the bird in front.
They’re not just putting themselves in the right position but they’re doing the right thing when they’re in that position…and that right thing is they’re timing their wing beats perfectly to match the good air coming off the bird in front. And what it means is that the bird in front’s wing tip is doing this, with the good air coming off it and the other bird that’s following makes sure that its wing tip takes the same path through the air. So its wingtip is in the upwash throughout the flap cycle. So it’s really maximizing their ability to capture this upwash. Somehow they’re sensing this coming off the bird in front.
What they were able to do is amazing when you think how dynamic the environment is. They’re up there in the sky in this huge 3D environment and despite that they’re able to somehow 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.