| Title | Feathered Flock Fluidity Finally Figured | |
| Date | Monday July 28 2014, @10:22AM | |
| Author | azrael | |
| Topic | ||
| from the flapping-fantastic dept. | ||
In a fascinating read, Science Mag describes new research on the seemingly perfectly coordinated turns of large flocks of birds.
Long a topic of speculation and study, these turns were even attributed to telepathy by ornithologists in the 1930s. In the 1990s the proposed theory, that each bird simply matches the direction of an adjacent bird's turn, didn't adequately explain in detail how the flock turns as one, and didn't explain why there were few if any stragglers. Even studies as late as 2011 suggested "each starling was connected to every other" by some unknown mechanism.
In the new study, the team, led by physicists, used high-speed cameras to film starlings, which form spectacular synchronized flocks. There is no "connection", simply a self preservation instinct and rapid information signaling.
Using tracking software on the recorded video, the team could pinpoint when and where individuals decide to turn, information that enabled them to follow how the decision sweeps through the flock.
The tracking data showed that the message to turn started from a handful of birds and swept through the flock at a constant speed between 20 and 40 meters per second. That means that for a group of 400 birds, it takes just a little more than a half-second for the whole flock to turn. The birds mimic not only the direction but also the sharpness of the turn of neighbors in three dimensions. Information about direction changes propagates across the flock with a linear dispersion law and negligible attenuation.
The fact that the information telling each bird to turn moves at a constant speed contradicts the 1990's model, and explains in detail how the signal flows through the flock to precisely coordinate turns which are signaled by which ever birds happen to be on the leading edge or the edge nearest a threat. The signal's speed and near absence of attenuation, mislead earlier investigators into imagining some "connection".
Being physicists, the researchers couldn't help but notice that the formula modeling this process was mathematically identical to the equations that describe superfluid helium. When helium is cooled close to absolute zero, it becomes a liquid with no viscosity at all, exhibiting a cohesion that's mathematically similar to a starling flock.
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printed from SoylentNews, Feathered Flock Fluidity Finally Figured on 2024-04-23 13:24:10