look! up in the air! it’s a bird! it’s a plane! no, it’s a bird. hey there flappy birds, jules here for dnews! you’ve probably seen birds migrating, orjust making short trips for feeding, and you’ve probably noticed that birds tend to fly ina v-shape. there’s usually one bird up at the frontleading the way, and each successive bird
lines up back and to the right or left ofthe bird in front of it. there are other basic shapes, such as j-formations,and inverted versions of both, and these groups are actually types of “echelon formationsâ€,meaning that they line up linearly. v-formations have been used extensively, notjust by birds, but by military generals. from the earliest days of war, allegedly stemmingback to when the thebans were fighting the spartans in 4th century bc, all the way totoday, the formation is used in sea battles and aerial warfare. birds, planes, boats, and people all havesimilar reasons for doing this. lining up in a v gives each member a clearline of sight ahead of them.
in some cases, it also takes less energy totravel in this formation. see, when a bird flaps it’s wings, a vortexof air directly behind it is pushed downward, called ‘downwash’. the air further back and to the sides respondsby pushing up, called ‘upwash’. any bird situated in another bird’s upwashhas to expend less energy to stay aloft, since they’re already being pushed upwards, anda v-formation situates each member back and to the side, directly in its neighbor’supwash. in 2001, researchers at the french nationalcenter for scientific research put heart-rate monitors on pelicans flying in v-shapes, andthey found that the ones farther back had
slower heart rates and did not have to flaptheir wings as often to stay afloat. in fact, there was an 11-14% total energysavings for the birds. another study from the proceedings of thenational academy of sciences also found that the flock also tries to makes sure that thebird up front doesn’t get too tired. since it doesn’t receive any benefits fromthe communal upwash. the leader bird rotates among the flock, althoughscientists still aren’t sure if there is a hierarchy of who “gets†to be the leader. of course, all this mess could be avoidedif we taught birds how to order plane tickets. one bird, the arctic tern, flies roughly 56,000miles round-trip and is able to sleep while
in flight. but how does the tern, and plenty of otherbirds pull off the ability to sleep mid-air? find out in this video. and do you have any animal questions for us? ask us in the comments, don't forget to subscribe,and come back here for more dnews every day.