Starling Murmuration
An example of global community

"From bird flocks to fish schools, animal groups often seem to react to environmental perturbations as if of one mind. Most studies in collective animal behavior have aimed to understand how a globally ordered state may emerge from simple behavioral rules. Less effort has been devoted to understanding the origin of collective response, namely the way the group as a whole reacts to its environment. Yet, in the presence of strong predatory pressure on the group, collective response may yield a significant adaptive advantage. Here we suggest that collective response in animal groups may be achieved through scale-free behavioral correlations. By reconstructing the 3D position and velocity of individual birds in large flocks of starlings, we measured to what extent the velocity fluctuations of different birds are correlated to each other. We found that the range of such spatial correlation does not have a constant value, but it scales with the linear size of the flock. This result indicates that behavioral correlations are scale free: The change in the behavioral state of one animal affects and is affected by that of all other animals in the group, no matter how large the group is. Scale-free correlations provide each animal with an effective perception range much larger than the direct interindividual interaction range, thus enhancing global response to perturbations. Our results suggest that flocks behave as critical systems, poised to respond maximally to environmental perturbations."

Below are several videos of Starling birds exhibiting what has been called swarm intelligence, murmuration, or scale-free correlation. These behaviors can be a GREAT example for humans who need to "see" how to work together for the benefit of all life.

One Shared Myth

The murmuration of Starlings could be a useful model for global community.

- John Burch

Oct 10, 2020

Watch this [VIDEO].

Apparently, from studies done at Princeton University and elsewhere, these birds manage to fly together by relating to exactly seven others. Not six, not eight. Seven.

I wonder why?

There is no leader. No one is "in charge."

The birds fly successfully together by adopting and sharing the ego of the whole.

• Could we learn from this as we move into the unknown? (see post 46)
• Is there a lesson here as we attempt to become a global community? (see posts 45, 47).
• What principles (see post 59) do these birds have, or need to have, to fly together?

There are many images of starlings and murmuration on the Internet. The one at the top of this post is interesting to me as it appears the birds are forming the image of a bird, flying from left to right.

Here is another [VIDEO] to ponder.

An Article from Cornell Labs

So how do these masses of birds move so synchronously, swiftly, and gracefully? This isn’t an idle question—it has attracted the attention of physicists interested in how group behavior can spontaneously arise from many individuals at once. In 2010, Andrea Cavagna and colleagues at the National Council of Research and the University of Rome used advanced computational modeling and video analysis to study this question. They found that starling flocks model a complex physical phenomenon, seldom observed in physical and biological systems, known as scale-free correlation.

Surprising as it may be, flocks of birds are never led by a single individual. Even in the case of flocks of geese, which appear to have a leader, the movement of the flock is actually governed collectively by all of the flock members. But the remarkable thing about starling flocks is their fluidity of motion. As the researchers put it, “the group respond[s] as one” and “cannot be divided into independent subparts.”

When one starling changes direction or speed, each of the other birds in the flock responds to the change, and they do so nearly simultaneously regardless of the size of the flock. In essence, information moves across the flock very quickly and with nearly no degradation. The researchers describe it as a high signal-to-noise ratio.

This scale-free correlation allows starlings to greatly enhance what the researchers call “effective perceptive range,” which is another way of saying that a starling on one side of the flock can respond to what others are sensing all the way across the flock—a huge benefit for a starling trying to avoid a falcon.

Last week, a new study on starling flocks appeared in the journal PLOS Computational Biology. The researchers, led by George Young at Princeton, did their own analysis of murmuration images to see how the birds adjust to their flockmates. They determined that starlings in large flocks consistently coordinate their movements with their seven nearest neighbors. They also found that the shape of the flock, rather than the size, has the largest effect on this number; seven seems optimal for the tightly connected flocks that starlings are known for.

Imagine a game of telephone: one person passes a message along to the next person, who repeats it to another, and so on. For humans, the telephone message loses information very quickly—that’s what makes the game fun. The first finding, by Cavagna’s team, suggests that very little information is lost in a starling flock. The second finding, by Young’s team, suggests that starlings “play telephone” with their seven nearest neighbors. Somehow they are able to process messages from those seven neighbors all at once, and this is a part of their method for achieving scale-free correlation.

Still, neither finding explains how starlings are capable of such extraordinary collective responses. As the researchers admit, “How starlings achieve such a strong correlation remains a mystery to us.”

Murmurations remind us that nature’s beauty can take limitless forms, and can shock and inspire us. A number of commenters on the River Shannon video mention a feeling of connection that they experienced while watching the video. It’s as if seeing that synchrony, that seemingly perfect connection between each starling, also reminds us to value our connection to the world around us, for connection can be truly beautiful.


Abstract

From bird flocks to fish schools, animal groups often seem to react to environmental perturbations as if of one mind. Most studies in collective animal behavior have aimed to understand how a globally ordered state may emerge from simple behavioral rules. Less effort has been devoted to understanding the origin of collective response, namely the way the group as a whole reacts to its environment. Yet, in the presence of strong predatory pressure on the group, collective response may yield a significant adaptive advantage. Here we suggest that collective response in animal groups may be achieved through scale-free behavioral correlations. By reconstructing the 3D position and velocity of individual birds in large flocks of starlings, we measured to what extent the velocity fluctuations of different birds are correlated to each other. We found that the range of such spatial correlation does not have a constant value, but it scales with the linear size of the flock. This result indicates that behavioral correlations are scale free: The change in the behavioral state of one animal affects and is affected by that of all other animals in the group, no matter how large the group is. Scale-free correlations provide each animal with an effective perception range much larger than the direct interindividual interaction range, thus enhancing global response to perturbations. Our results suggest that flocks behave as critical systems, poised to respond maximally to environmental perturbations.

More

Collective response is the way a group as a whole reacts to its environment. It is often crucial for a group, or for subsets of it, to respond coherently to perturbations. For gregarious animals under strong predatory pressure, in particular, collective response is vital. The remarkable thing about a flock of birds is not merely the globally ordered motion of the group, but the way the flock dodges a falcon's attack. Collective response is the trademark of self-organized order as opposed to a centralized one. Consider a group where all individuals follow a leader, without interacting with one another. Such a system is strongly ordered, as everyone moves in the same direction. Yet, there is no passing of information from individual to individual and hence behavioral fluctuations are independent: The change of direction of one animal (different from the leader) has very little influence on that of other animals, due to the centralized nature of information transfer. As a consequence, collective response is very poor: Unless detected directly by the leader, an external perturbation does not elicit a global reaction by the group. Response, unlike order, is the real signature of self-organization.

In self-organized groups the efficiency of collective response depends on the way individual behavioral changes, typically forced by localized environmental perturbations, succeed in modifying the behavior of the whole group. This key process is ruled by behavioral correlations. Correlation is the expression of an indirect information transfer mediated by the direct interaction between the individuals: Two animals that are outside their range of direct interaction (be it visual, acoustic, hydrodynamic, or any other) may still be correlated if information is transferred from one to another through the intermediate interacting animals. The turn of one bird attacked by a predator has an influence not only over the neighbors directly interacting with it, but also over all birds that are correlated to it. Correlation measures how the behavioral changes of one animal influence those of other animals across the group. Behavioral correlations are therefore ultimately responsible for the group's ability to respond collectively to its environment. In the same way, correlations are likely to play a fundamental role in other kinds of collective decision-making processes where informed individuals (e.g., on food location or migration routes) can extend their influence over many other group members.

Of course, behavioral correlations are the product of interindividual interaction. Yet interaction and correlation are different things and they may have a different spatial (and sometimes temporal) span. Interaction is local in space and its range is typically quite short. A former study shows that in bird flocks the interaction range is of the order of few individuals. On the other hand, the correlation length, namely the spatial span of the correlation, can be significantly larger than the interaction range, depending chiefly on the level of noise in the system. An elementary example is the game of telephone: A player whispers a phrase into her neighbor's ear. The neighbor passes on the message to the next player and so on. The direct interaction range is equal to one, whereas the correlation length, i.e., the number of individuals the phrase can travel before being corrupted, can be significantly larger than one, depending on how clearly the information is transmitted at each step.

Although the correlation length is typically larger than the interaction range, in most biological and physical cases it is significantly smaller than the size of the system. For example, in bacteria the correlation length was found to be much smaller than the size of the swarm. In this case parts of the group that are separated by a distance larger than the correlation length are by definition independent from each other and therefore react independently to environmental perturbations. Hence, the finite scale of the correlation necessarily limits the collective response of the group.

However, in some cases the correlation length may be as large as the entire group, no matter the group's size. When this happens, we are in the presence of scale-free correlations. The group cannot be divided into independent subparts, because the behavioral change of one individual influences and is influenced by the behavioral change of all other individuals in the group. Scale-free correlations imply that the group is, in a strict sense, different from and more than the sum of its parts. The effective perception range of each individual is as large as the entire group and it becomes possible to transfer undamped information to all animals, no matter their distance, making the group respond as one. Here, we provide experimental evidence that bird flocks exhibit scale-free correlations and we discuss under what conditions such correlations may arise in animal groups.

A model of global community exists! We can learn from it.

- John Burch

Oct 11, 2020

Scale-free correlation gives a long and effective perception range to individual agents which is much larger than the direct inter-individual (agent-agent) interaction range. This means that any small change in one agent causes change in the whole group.

Wow! Double wow!

I believe we have, here, a viable model for emerging the global community we seek!

To watch the uncanny synchronization of a starling flock in flight is to wonder if the birds aren’t actually a single entity, governed by something beyond the usual rules of biology. New research suggests that’s true.

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.

In starlings, “being critical is a way for the system to be always ready to optimally respond to an external perturbation, such as predator attack,” wrote researchers led by University of Rome theoretical physicist Giorgio Parisi in a June 14

Parisi’s team recorded starling flocks on the outskirts of Rome. Some had just over 100 birds, and others more than 4,000. Regardless of size, the correlations of a bird’s orientation and velocity with the other birds’ orientation and velocity didn’t vary. If any one bird turned and changed speed, so would all the others.

In particle physics, synchronized orientation is found in systems with “low noise,” in which signals are transmitted without degrading. But low noise isn’t enough to produce synchronized speeds, which are found in critical systems. The researchers give the example of ferromagnetism, where particles in a magnet exhibit perfect interconnection at a precise, “critical” temperature.

“More analysis is necessary to prove this definitively, but our results suggest that starling flocks are a critical system," said study co-author Irene Giardina, also a University of Rome physicist.

According to the researchers, the “most surprising and exotic feature” of the flocks was their near-instantaneous signal-processing speed. “How starlings achieve such a strong correlation remains a mystery to us,” they wrote.

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Of all distinctive traits of collective animal behaviour the most conspicuous is the emergence
of global order, namely the fact that all individuals within the group synchronize to some
extent their behavioural state. In many cases global ordering amounts to an alignment
of the individual directions of motion, as in bird flocks, fish schools, mammal herds and in
some insect swarms. Yet, global ordering can affect also other behavioural states, as it
happens with the synchronous flashing of tropical fireflies or the synchronous clapping in
human crowds.

The presence of order within an animal group is easy to detect. However, order may
have radically different origins, and discovering what is the coordination mechanism at the
basis of order is not straightforward. Order can be the effect of a top-down centralized control
mechanisms (for example, due to the presence of one or more leaders), or it can be a bottom up self-organized feature emerging from local behavioural rules. Distinguishing between
these two types of global ordering is not trivial. In fact, the prominent difference between the
centralized and the self-organized paradigm is not order, but response.

Collective response is the way a group as a whole reacts to its environment. For
gregarious animals under strong predatory pressure collective response is vital. The
remarkable thing about a flock of birds is not merely the globally ordered motion of the
group, but the way the flock dodges a falcon’s attack. Collective response is the trademark of
self-organized order as opposed to centralized one. Consider a group where all individuals
follow a leader. Such system is strongly ordered, as everyone moves in the same direction.
Yet, there is no passing of information from individual to individual and hence behavioural
fluctuations are independent: the change of direction of one animal (different from the leader).

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They call it "scale-free correlation," and it means that no matter how big the flock, "If any one bird turned and changed speed, so would all the others."

It's a beautiful phenomenon to behold. And neither biologists nor anyone else can yet explain how starlings seem to process information and act on it so quickly. It's precisely the lack of lag between the birds' movements that make the flocks so astonishing. Having imported a theoretical physicist to model the flock movement, perhaps a computer scientist would be the right choice to describe the individual birds' behavior.

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Biologists speak about a “Superorganism” as an organism consisting of many organisms capable of using a collective intelligence unknown to the single individual.

Watch this example of Swarm Intelligence.