How Do Starlings Murmurate?

As the light dims on an autumnal or winter’s evening, starlings will rise from their communal roosting site and wheel and swoop as if one body, moving seamlessly and effortlessly out of one geometric pattern into another, seemingly under the command of a great choreographer in the sky. These stunning displays begin at the start of the starlings’ roosting season, as early as September or as late as the end of November, and can last throughout the winter.

The technical name for this phenomenon is a murmuration, which, by extension, has become the collective noun for a group of starlings. Derived from the mediaeval Latin noun murmuratio, meaning murmuring or grumbling, it is thought to be an onomatopoeic representation of the noise the birds make when they are in flight. While murmurations are not unique to starlings, other birds, such as geese, fly in formalised V-formations to assist in navigation, the term is especially associated with them.

What intrigues the curious of mind is how the starlings perform their acrobatics, moving in perfect synchrony, without bumping into each other and landing in an unseemly heap on the ground. Back in 1931 British ornithologist, Edmund Selous, in his book, Thought-transference (or what!) in birds, surmised that starlings used psychic powers to operate in a flock and avoid colliding. More recently Giorgi Parisi, from the University of Rome, has applied his deep knowledge of theoretical physics to give a more rigorous answer to the problem.

2020 might be characterised as the year of the ultracrepidarian with many of us becoming overnight epidemiologists, talking with faux confidence about R numbers and rates of infection. In reality, all that has happened is that we have gained a better understanding of basic statistical concepts, not least how numbers rise exponentially and the compound effect that even a small event, like the flap of a butterfly’s wing in chaos theory, can have on the whole. It is this understanding that we need to make sense of Parisi’s research.

In a paper published in 2010 in the Proceedings of the National Academy of Science, Parisi looked at how the speed at which one starling flew affected the velocity of the rest. He discovered that the behaviour of one animal affects and is affected by that of all the others in the group, no matter how large or small the group is. A starling changing speed will trigger a corresponding change in the speed of the other birds in the group. Acting as a group they have a wider perception range than they would have as individuals. Drawing upon an analogy from ferromagnetism, Parisi observed that a magnet’s particles showed perfect interconnection at a precise, “critical” temperature. Starlings’ murmurations were just such a critical system and were formed when conditions and group dynamics were optimal.

It took a further paper from Parisi and his team, published in 2012, to explain how a single bird could spark a change in movement in a formation that was busily responding to the actions of others and how that reaction could cause such a speedy response within the group. Rather than looking at speed, which was the focus of the earlier paper, they looked at how a bird’s change of direction could affect those around it.

What they found was that one bird’s movement affected those of just seven of its immediate neighbours, but that the movement of each of its neighbours affected a further seven in its immediate vicinity, and so on, producing a compound effect throughout the flock. The result is a twisting, ever-changing formation where some parts move at one speed in one direction and others at different speeds in other directions. When a single starling changes direction or speed, the whole flock responds through the ripple effect of the power of seven, making it appear as if the information or a command has been passed through the flock in real-time.

The result is a fascinating and thrilling spectacle and one that can be performed in relative safety. And why seven? It seems that is one of those numbers that just seems to work in nature, where the balance between individual effort and group cohesiveness is optimised.

When next I see a murmuration of starlings, I will raise my hat to the power of seven.

This is an abridged version of an article that appeared on Country Life’s website. To see the full  article, go to

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