Why Do Birds Fly in V-Formations?
FAQ in Science #1
In sweltering Greater Los Angeles, it's that wonderful time of year again. For the first time in months, it's actually enjoyable to be outside! The new season's cool winds bluster from the northeast, forcing out the hundred-degree-plus weather that kept us all cowering under shade. And, in my neck of the woods, a familiar honk rings in the fresh autumn breeze.
Canadian Geese. In gaggles, they fly over the San Fernando Valley to their winter retreats. Through closed windows, over the hum of a rumbling AC, sounds the honk-a-lonk of hundreds of flying Canadian tourists.
As a kid, I adored watching them fly by. Their strange V flying pattern was unmistakable and surprisingly impeccable! I often wondered why they chose to do something that seemed like so much additional effort. "Why would these birds fly in a V? Why not just fly in a chaotic swarm like the other flocks I've seen?"
After many years of study and a newfound hobby in birding, I finally found the answer.
Why do some birds travel in v formations? Because they've learned a trick or two by being frequent flyers.
Working Smarter
If you've ever been towed behind a boat, you've likely noticed that the center isn't the best spot to be. Getting pulled straight behind a pontoon is a bumpy, uncomfortable ride. The best rides are when your captain makes twists and turns that cause you to hit the wake behind the boat. In a narrow section, your tube hits a sweet spot that's smooth, easy, and breezy.
In flock flight, a surprisingly similar phenomenon occurs. Except, instead of a water wake, our feathered friends are riding a sweet spot in the wake of air.
In this video below, you can see the wakes that are generated by bird flight. Vortexes of air are formed by a bird's wingtips and tail feathers:
In a study from 2001, a scientist named Henri Weimerskirch found that pelicans who use these air wakes have increased flying efficiency. In his experiment, where he attached small heart monitors to a flock of pelicans, he discovered that pelicans towards the back of the V-formation had significantly lower heart rates. Considering just how much effort it is for birds to keep in flight (see this goose heart rate study for more info), this formation could save a massive amount of energy for long-distance flyers like pelicans and geese.
Birds of a Feather
With Weimerskirch's study, scientists had a good idea of the benefits of this flight formation and a great way to test it. Pairing this new idea with a wealth of flight physics studies helped confirm the notion. But, alas, the reason why some birds chose to do this was still pretty fuzzy.
In the 2010s, a proper answer finally began to emerge. In 2015, a team of researchers at the University of Oxford noticed that northern bald ibises changed their positions in these V-formations rather frequently! In the group they studied, the scientists found that a pair of birds was switching off being the frontrunner.
The swapping they noticed was rapid, and it indicated to the research team that a sort of reciprocal altruism was taking place. Reciprocal altruism is a behavior where an individual makes a sacrifice to help another individual, with the expectation that the other individual will return the favor later. Much like you might pay for a friend's lunch with an understanding that they'll pay for yours next time, birds are displaying this effort-trading behavior to each other while in the air!
Interestingly, this behavior might be unique to flight relationships. The relationships and willingness to cooperate by the same flock of individuals appeared different when not flying in a V. More research is necessary to confirm whether V-formation birds have evolved a flight-specific form of cooperation.
Nature or Nurture?
Scientists are still sorting out the specifics, but the working hypothesis is that this behavior is self-taught. In a V-formation experiment in 2013, to the surprise of the human participants, scientists were able to help teach ibises a modification of the behavior. When they first began, the birds were reportedly not very good at the behavior. But, with practice, they began to refine their methods in an impressive display of autodidactic reasoning.
But, researchers aren't yet all convinced. A single study is, of course, not enough to make a theory or law out of.
Though this debate is still underway, and many studies are needed to confirm the phenomena's reasoning, this author (hello, reader!) is inclined to suppose that most v-formation species build the skill of wake-flight as they go. Much like how we can practice wakeboarding or riding an innertube behind a boat, birds might just be working on their own ability to fly in the right spot (and correct technique) on their air-wake.
About the Creator
Olivia L. Dobbs
Science Enthusiast, Naturalist, Dreamer, Nerd.
I crosspost my Medium articles here :)
You can find my main account on Medium: https://medium.com/@oliviadobbs13
Check out my science! -> bit.ly/DobbsEtAl
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