Doing Maths on the Fly, Birds Form V for Efficiency


Across the globe, hundreds of species of birds can be seen flying in V-formations. We have long suspected that these formation might help birds fly with less effort. Yet the precise mechanics have remained unknown – until now.

Expending less effort in long flights can be the difference between life and death for migratory birds. Higher efficiency saves precious fuel needed for journeys that can often be thousands of kilometres long. Cyclists in Tour de France know this well.

These cyclists ride in a group called the peloton where the leader plows through the onrushing air, while teammates riding behind him burn fewer calories. After some time, the leader swaps places to spread out the effort among the group.

Just like cyclists, it might seem intuitive that birds do the same when flying in a V-formation. But flying is complicated by the fact that birds flap their wings, which changes how the air flows around them.

Aerodynamic theory predicts birds should save energy if they carefully adjust their position and flapping speed in a formation. This made some scientists question whether birds have the required sensory precision to achieve this feat in mid-air.

In a study just published in Nature, an international team led by Steven Portugal of the Royal Veterinary College in London shows that birds defy these expectations: they really can fine-tune their flight formations to be more efficient.

As the crow flies

When a bird flies, it creates spinning loops of air behind it called vortices. Part of the vortex system pushes air upwards– known as upwash – while the opposite side of the vortex pushes air downwards – known as downwash. To fly with less effort, a bird should time its flapping to press its wings through the upwash created by the bird in front of it. It also wants to avoid the downwash.

By precisely recording the spacing of ibises in formation, along with the timing of their wingbeats, Portugal and colleagues were able to show that ibises time their wingbeats for maximum efficiency. That is, they take advantage of the upwash and avoid the downwash. The ibises also altered their wingbeat patterns based on the style of formation: birds flying in a “V” formation timed their movements differently to those flying in a single file line, just as they need to for maximum efficiency.

(Markus Unsold)

The research was done using rare northern bald ibises. These large birds are the subject of a special conservation program to reintroduce them to the wild. Those used in the study hatched at Zoo Vienna, Austria, in March 2011, and were “imprinted” with human foster parents, which allowed the humans to train them in basic survival skills, just as their real parents would have. This they could achieve, because some birds get “imprinted” by the first suitable moving object they encounter during a critical period shortly after hatching. They then follow and learn from this surrogate like they would from a biological parent.

At four months, the birds began doing training flights behind an ultralight aircraft. They were then led along a migration route from Austria to Italy, the route they would then follow in the future when released into the wild.

The ibises were fitted with tiny location loggers and their flight filmed. They flew in formation with one another, following the path set by the paraplane. When the flapping speed and positioning of the birds was analysed after the journey, Portugal found the timing matched what theory predicts the birds should use to maximise their efficiency.

The team used ibises because they had special access to captive-raised birds, but other birds probably use the same trick when they fly in formation. How these birds are able to sense and predict such subtle changes in air flow is still a mystery.

It may be that birds have sensory abilities we weren’t previously aware of. It might also be that ibises, and possibly other birds, have an innate ability to do the required mathematics, quite literally, on the fly: judging the distance to the next bird and counting wingbeat cycles as they go. Either way, it is clear that birds still have a lot to teach us about their abilities and success as flying animals. 

 

Michael Habib does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.The Conversation

This article was originally published at The Conversation. Read the original article

*Image of birds flying in v-formation via Shutterstock.


  • TapestryMood

    Fascinating!

    • rg9rts

      Morning tap Are we annoying anyone this morning or just spreading the wealth of our knowledge?

      • TapestryMood

        You had the knowledge…I just had the ohhhh and ahhhh:-)
        MONSTA was a good =^.^= this morning?

        • rg9rts

          You are on drugs right ? MONSTA behave?? Oxymoron.

          • TapestryMood

            Baaaaad rg…He is lovable ..Nice kitty, kitty…ignore that curmudgeon.
            No, I am not annoying anyone tonight…this morning…just wanderin’ the cyber, sort of lost today…How are you?

          • rg9rts

            Doing the same have to get away from the square to see who else is out here. Nice kitty isn’t stupid kitty. He knows who has the feedbag for him. He is watching me but not snoring yet. We amuse one another constantly….

          • TapestryMood

            I just amused myself seeing who is nominated for the Razzies..all excellent choices..IMO..even though I didn’t see any of them…;-P

          • rg9rts

            That is usually the best.
            So what does star this discussion mean?

          • TapestryMood

            ?? Lost me..what? You mean star the article?
            I guess it gives kudos the the authors..and a count of readers?? So, I do it to let them know I have read them, even when I don’t comment.

          • rg9rts

            At the top opposite the comment count is a gold star and numbers???

          • TapestryMood

            Yes..it’s what I said…click it and it gives Epoch info..your click just counts once, though…if you look at our Epoch Chat Forum about 60 or 70, now. I usually try to mention clicking it so Epoch knows;-)

      • TapestryMood

        ?? I gave you an ^ arrow and it says -1..wtf?

      • TapestryMood

        Hmmm..I refreshed and the ^ and -1 disappeared, so did it again and all is ok..weird stuff;-)

        • rg9rts

          You have to have more than 1 character.

          • TapestryMood

            ? It has always worked just clicking the ^.
            DON’T EXPLAIN…lol..all ok.

          • rg9rts

            I have no idea I’m new to this stuff.Anyone that hacks this unit will die of terminal boredom.

          • TapestryMood

            :-D We are copacetic on that.
            I love watching the Canadian Geese V’s formations here….honking, swerving, but oh, the local golf courses..ack…goose poop is thick on many;-)

          • rg9rts

            I used to have a house on a lake with a dock. You can’t imagine the gifts I was given by the geese.

          • TapestryMood

            :-D But, how wonderful to have lived there! I have such an ache/yearning to live by the ocean, even our cold Washington coast…will be doing so…in the future..at least a couple of months a year…It has always been my solace and renewal and haven’t even been in over 5 years..sigh.
            Back to geese…just hosing off my golf shoes was enough for me…and making sure hub did not put tees in his mouth…or lick his balls..men do it all the time, yuck..LOL..NO COMMENT!!!;-)
            Did you check out the Science Section: Beyond Sunsets-Beyond Northern Lights..truly amazing…When I am in a mood like today, tonight, I go to nature and science wonders..sooth me..

          • rg9rts

            Do you remember the Johnny Carson bit when he interviewed Jack Nicklaus’ wife? He ask her if she did anything for him before a big tournament and without missing a beat OR realizing what she was saying said I kiss his balls……..Drum Roll!

          • TapestryMood

            I thought that was sort of a “folk tale” that just keeps making the rounds? Did you really see it? LOL..She is such a nice woman and Jack is an azz..but, my father loved him from the time he was a college player, on…
            My favorite was the “hatchet throw”..;-)

          • rg9rts

            No NO I saw the clip….Michael Ansara could never live that one down Cochice!

          • TapestryMood

            Well..they sort o looked alike, but it was one of the Ames Brothers…Ed, maybe?.

          • rg9rts

            One of them hollywood injuns I guessed myself

          • rg9rts

            I’ll check out sciences later, I go there environment and of course videos for my latest fix on animals

          • TapestryMood

            :-D I see we have similar tastes..I used to post long, detailed, factual info on Keystone ..and those a-hole trolls just kept the lies about jobs and lowering our gas prices..freaking idjiots..If the Ogallala Aquifer gets spills,..man!

          • rg9rts

            Did those idiots ever wonder why the gas prices haven’t come down now that the US is an oil EXPORTER not an importer any longer??

          • TapestryMood

            They have no clue about truths on ANY issue..period.
            No matter how often you explain how it all goes on the world market, they don’t care or don’t understand.. ..could never get them to understand China’s role in the hideous oil from Canada, if all the pipe links get OK’d..sigh..

          • rg9rts

            Koch mouthpieces,

          • TapestryMood

            Exactly..just like the elected in Congress-House/Senate…and state legislatures…Kochs. ..Big Coal…Oil companies..Monsanto… et al..(.Propaganda United R Us)..and Citizens United ruling just lets them keep feeding the lies..sigh….ALEC is still alive even though journalists have ignored it again…
            Well, it’s been nice connecting with you…I am off to bed….give MONSTA an ear ruffling/tummy rub for me;-) Hope you have a good day..

          • rg9rts

            Nite Nite sorry to rile you up!Sleep well dear and say hi to hubby for me.

          • TapestryMood

            I have “riled” below the surface 24/7…no problem;-) Thank you..I will..You take care..

  • rg9rts

    To really see this in action ignore the peloton and watch the breakaway of several riders from different teams working in unison with lead in constant change as they ride in a line the old leader drifts back while the new one leads for a minute or so. there is always a fresh rider leading and the speed grows.

  • OnyxE

    Geese are famous for their V formation flying and there is a name for this…vortex surfing. The US Airforce is already talking about learning to fly like geese so they can save millions on fuel.

    http://complex.foreignpolicy.com/posts/2013/07/18/how_geese_will_save_the_air_force_millions_of_dollars


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