A starling murmuration, hundreds or thousands of birds moving together as one, is one of nature’s most extraordinary sights.
Scientist Grainger Hunt writes, these aerial spectacles are caused by a falcon near the edge of the flock. It turns out that the beauty of a murmuration’s movements often arises out of defense, as the starlings strive to put distance between themselves and the predator.
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 responds 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.
Researchers 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. Findings suggest 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.”
From an 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. We found that the range of 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.
Has the Creator taught us something about the unity of His Church through creation? (Galatians 5:11, 6:12)