Aerobatic Geese

[The500man]

Slow-mo video (http://www.newscientist.com/blogs/nstv/2012/01/first-slow-mo-video-of-goose-flying-upside-down.html?DCMP=NLC-nletter&nsref=goose) of geese rolling inverted to slow down for a landing! There's also a link to an aerobatic fly! Nature is cool right? :cool:

[Flying Binghi]

Looks like them geese got to a higher plain of lernin..:)

“Why is it,” Jonathan puzzled, “that the hardest thing in the world is to convince a bird that he is free, and that he can prove it for himself if he’d just spend a little time practicing? Why should that be so hard?” via Johnathan Livingston Seagull





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[welliewanger]

Definitely worth a gander :E

[BackPacker]

It's definitely a nice video and an interesting phenomenon, but I doubt whether the commentary is accurate.

Upside down wings generate more drag causing a goose to slow down quickly

Although I agree with the first part (upside down wings generate more drag), I doubt whether geese (or birds in general) are able to properly fly, or float, upside down. In the sense that they fly level and their bodies experience minus 1G.

Birds are "high wing" creatures for a reason: Muscles can only generate tension, not compression. So they need to be underneath the wing, just like the strut on a C172. At the other end they are attached to the breast bone which is comparatively huge, compared to non-flying animals.

Now turn the bird upside down so that it flies inverted properly. Where are the muscles and the attachment points that are able to sustain these forces?

Personally I think what they're doing is a sort of barrel roll, but from level flight. This allows them to rapidly lose height without picking up a lot of speed. In the video you can see that the bird in the upper right corner of the frame loses height rapidly, in what seems to me a more or less ballistic flight path. So they're not properly flying inverted (-1G). As a result of that, you cannot claim that their wings are inverted, and that that creates a lot of drag.

Nevertheless, very nice video. Shame it ends so quickly.

[abgd]

Now turn the bird upside down so that it flies inverted properly. Where are the muscles and the attachment points that are able to sustain these forces?I can't see the video from here, but assuming the bird intends to lose height, it won't need to flap its wings. It only needs to hold them extended and - though I don't know avian anatomy well - certainly has muscles to enable it to do this, though they won't be as strong as the muscles powering the downstroke. After all, if you watch birds at rest, they move their wings upwards to preen. Hummingbirds almost certainly have an active upstroke as well as downstroke, and humans have flexors and extensors and abductors and adductor muscles for all the relevant axes.

But... Interesting point. Perhaps there is some more subtle reason for the maneuver.

[Shaggy Sheep Driver]

Interesting, but I doubt they are doing it to lose height, as they are still flapping which indicates they are using energy to maintain or gain height. Why would they keep flapping if they wanted to descend? They'd just go to high AoA, dangle their legs, feet outstretched for max drag, and perhaps roll 30 degrees or so side to side.

They would certainly stop flapping!

I find it quite common that ornithologists just don't understnd even the most basic principles of flight!

[Brian Abraham]

I believe it's a just for fun manoeuvre, something done for the joy of it. When sitting on off shore oil rigs is common to see sea gulls disporting them selves in the same fashion.

[gaxan]

It's well known that Ducks cannot fly inverted - otherwise they would quack up !! BOom boom !

[rmac]

Used to feed the sea eagles from the back of my boat in Langkawi.

We would throw chicken bits on the water and they would launch from their cliff top nests, tuck everything in and come down like a freefall bomb...and at the last minute throw everything out, max brakes, stopping just short of the water to grab the bits with their talons...

Never ever tired of watching natures aerodynamics at work :)

[hhobbit]

they have learned to avoid gentle descents, more target time for shooters. Said so on one or two links in.

[tmmorris]

Totally agree, every time I watch a bird fly I am awed by the subtletly of it all - drag control, AoA control &c. Even a pigeon; but the bigger the bird, the easier it is to see it all happening (it's all too quick on a sparrow!)

Tim