02 December 2011

A murmuration of starlings


Filmed in Ireland, on the River Shannon, and posted at Vimeo, where it has garnered over 700 comments.  The video is particularly nice for the combination of the aerobatics, the music chosen to replace wind sounds, and the steady hand of the young woman filming from a canoe!

Still photos and a video of starlings in Scotland are also posted at Poemas del rio Wang.

How (and why) they do this is still a bit of a mystery.  The science is discussed at Wired Science.
Mathematical analysis of flock dynamics show how each starling’s movement is influenced by every other starling, and vice versa. It doesn’t matter how large a flock is, or if two birds are on opposite sides. It’s as if every individual is connected to the same network.

That phenomenon is known as scale-free correlation, and transcends biology. The closest fit to equations describing starling flock patterns come from the literature of “criticality,” of crystal formation and avalanches — systems poised on the brink, capable of near-instantaneous transformation.
What puzzles me is how they are able to sense the movement of the others, since birds don't have the lateral line sensors that some fish have.  I remember seeing immense flocks of starlings passing overhead above the parking place at my workplace in Indianapolis, Indiana many years ago - thousands and thousands of them, like a scene from the book Paradise Found (which I still need to write a post about).  Our concern in those years was that the roosts of those birds were sources of histoplasmosis.  But the flocks are truly amazing.

p.s. - re the word "murmur": Reduplication points to imitative, onomatopoeic origin. Cognate with Sanskrit मर्मर (marmara, rustling sound, murmur), Ancient Greek μορμύρω (mormúrō, to roar, boil), Lithuanian mùrmėti (to mutter, murmur, babble), Old High German murmurōn, murmulōn (to mumble, murmur), Old Norse murra (to grumble, mumble).

11 comments:

  1. Loved this when I first saw it. Just a few days later, I saw a murmuration pattern here in central Texas - it was the emergence of 1 million Mexican free-tail bats and they were flowing and morphing in bands all over the sky!
    Here's a photo:
    http://www.flickr.com/photos/26590582@N07/6442488737/

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  2. Hmm. link got truncated. I'll try again:

    www.flickr.com/photos/26590582@N07/6442488737/

    If that doesn't work, go to Flickr and search "bats round rock" for the pic from Jaguarfeather.

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  3. Good photo, David. Some people use the collective term "cloud" when referring to bats:

    http://users.tinyonline.co.uk/gswithenbank/collnoun.htm

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  4. It's actually not a complicated process. I once attended a workshop by the dancer Jennifer Monson, who in an open space in a museum taught about 30 people how to flock like birds. We began by heading in a single direction, and then when someone decided to shift direction, how easy it was for the people around him or her to shift also, with everyone eventually following. We did this for about ten minutes, with no accidents! Here's a website of Monson's--she does a lot of educational presentation like this, besides her own performances, many of which involve migratory bird travels:
    http://ilandsymposium.wordpress.com/bird-brain-educational-resource-guide/

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  5. Wow, David, that’s a great photo. I will insert a link to it in the Murmuration post on Río Wang.

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  6. I know this is a somewhat redundant question but how can they get anywhere flying this way? I would think that the only advantage to this would be to avoid predators because it can be in no way energy efficient. Similar to a school of fish, no?

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  7. it reminds me of a school of fish. very beautiful.

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  8. Lovely find!

    Birds have a huge field of vision, they can hear extremely well, and I'd bet they get a lot of pressure feedback from feathers via nerves in skin.

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  9. I saw a similar event last week while I was driving down the highway. Flock size was maybe a bit smaller than shown in this video, and a farther away. The distance may be an advantage however; it allows you to better visualize the changing patters. I am with anon 1:54 though in wondering what the purpose of this activity is. Maybe just a starling flash mob having fun? I know I enjoyed watching it!

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  10. It's relatively simple as other posters have pointed out. A guy figured out a few years back that by putting in an algorithm that said stay within a certain distance of your neighbor and follow him, but not too close or far... objects could be run in a program that mimics flock behavior very closely.

    His work gets used in the movies now when they animate flocks of animals, be it bees, bats, birds, etc.

    And to be fair, the patterns only look complex to us -from our viewpoint- as we watch ripples and twists run through the pattern. Much more complex would be a completely rigid and fixed 3 dimensional pattern that the birds held flying through the sky (like a Hexagonal bipyramid) whilst also turning and changing direction and rotation of said 3d shape.

    From the birds point of view it's just "follow fred, follow fred, woah! he slowed down, ok turn left, speed up. Crap! stay by bill, stay by bill," etc.

    The resulting patterns from external inputs, and the elasticity of their following distances and reaction times do become mesmerizing, though!

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  11. I don't want to take away from the beauty of the starlings, but as to their sensing ability, humans have a little over 180 degree field of view with eyes facing forward. I'm sure starling's FOV is near 360. Google 'boids' for the story of the computer simulation of flocking behavior(pretty much what beereg said). Interesting info on the dancer Monson, but see also: military close order drill since at least the Spartan hoplite. There is central control in COD, true, but alignment is judged by each individual.

    As to the video, the music was nice, but I wish the starling wings were the sole sound track.

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