Starling Murmurations – How And Why Do They Do It?

Starling Murmurations – How And Why Do They Do It?

Courtesy of Phil Baum, Unsplash

Have you ever been lucky enough to see a starling murmuration? It is one of nature’s most awe-inspiring spectacles. How do these birds make these formations without crashing into each other and why?

The word “murmurate” comes from the Latin murmare, to murmur, and is possibly one of the most onomatopoeic words used as the foundation for a collective noun.

If you’ve ever witnessed a starling murmuration and been close enough for it to pass overhead or at least nearby, you’d have to admit it’s the closest word you could get for a description of the noise that you hear.

It is a sound like no other, an ethereal mad fluttering whoosh of wings, like a rift in time being rubbed on a colossal polyester jumper.

The word ‘murmuration’ is used to name the weird, hypnotically unpredictable swirl and surge of so many birds.
Courtesy of Sudokuhani, Wikimedia Commons

The word ‘flock’ is used to describe a grouping of birds, but only when they are in a mostly linear form of movement, for example east to west or from that side of the field to the other. The word ‘murmuration’ is used to name the weird, hypnotically unpredictable swirl and surge of so many birds, moving together and yet individually, seemingly in a prearranged pattern, but spontaneously throughout.

Starlingsare famous for this behaviour, although other species like bees, bats, fish and bison murmurate, as well as other birds: raptors, geese, red knots, robins, flamingos, dunlins; all have been known to move about the sky in this way.

Starlings seem to be the flag-bearers of the word exclusively, though. This may be more to do with the sheer size of the group that comes together, combined with the relative ease of accessibility that we humans can get to view the spectacle. Starlings will perform this fantastic aerodynamism every evening just before dusk during the autumn and winter months, before they settle for the night.

Starlings usually roost in reedbeds, and there are some fine examples of that kind of habitat in many countries. With greater understanding of scientifically sensitive habitats like wetlands, more has been done to preserve this environment for birds than any other type.

Courtesy of Celuici, Wikimedia Commons

Murmuration sizes can be anything from a few hundred to millions of birds. In 1999 the largest one ever recorded was estimated to be over 6 million birds! This took place at Shapwick Heath in Somerset, UK, where a huge bird reserve exists.

The lanes and gateways surrounding this reserve are usually chock full of cars as people come from all over the country to try to witness the amazing sight of an evening murmuration.

Murmuration sizes can be anything from a few hundred to millions of birds.

But why do they do this? Surely it uses a lot of precious energy, but they do it anyway, without fail, every year. Scientists have come to agree this takes place for a few reasons:

  • Safety in numbers – despite creating an eye-catching display that will warrant a lot of attention, predators have a very hard time latching onto one specific bird when there are thousands of them confusingly wheeling about over more or less the same spot. Falcons and hawks will already be hanging around known roost locations, so it makes sense to band together to increase chances of survival. The sudden shift in patterns in a murmuration will usually have a bird of prey at the centre of them, desperately trying to catch one.
  • Shared heat – smaller groups gather from across the countryside from all directions to form this hyper-colony, boosted by migrants from the continent seeking out our comparatively warmer winters. This behaviour only occurs as the temperatures get colder and the weather gets worse. More feathers mean more warmth. When the birds suddenly finish their display and slide downwards into the reeds, like so many grains of rice being poured from a cup, they will roost there all night at an incredible density of 500 birds per cubic metre, until the dawn light stirs them upwards again.
  • Shared information – colder temperatures = less abundant food sources after the bountiful months of spring and summer, so this is highly likely a perfect opportunity to tell each other where the food is. This theory is known as the information centre hypothesis.

So those are the probable whys. What about the how? This question was largely unanswered until a few decades ago. But first, one of the earliest proposed explanations in 1930 was by our good friend Edmund Selous who pioneered the virtues of bird watching.

He suggested that the birds shared some kind of psychic ability, telepathy perhaps, for what other explanation could there be for so many birds to instantly know where to go all at the same time?

Later on, in the 50s, observation of other swarming groups like insects and fish showed that this movement wasn’t actually instantaneous, there was a microscopic delay between one creature moving one way and the next one following suit. But it wasn’t until the 1980s when advances in computer modelling showed what was actually happening.

Courtesy of Airwolfhound, Wikimedia Commons

In group dynamics, there are two types of large response behaviour: top-down control, instigated by a leader (think of the singer of a band clapping to the beat and the audience copying them), or self-organised, where the individual is responsible for the movement but has been influenced by the movement of another in close proximity. The dynamics of a murmuration made it quite clear that there was no leader; who was influencing who?

The dynamics of a murmuration made it quite clear that there was no leader.

In 1987, computer scientist Craig Reynolds managed to create a simulation of a flock of birds, calling the individuals “boids”.

The digital creatures only had to obey three simple rules: nearby boids would move further apart, boids would align their direction and speed, and more distant boids would move closer.

Famously, this model was then used in the 1992 Batman Returns film for a huge colony of bats and an army of penguins, and other films thereafter, so lifelike was the construct to what occurs in nature.

This model was the gateway for ever more advanced studies, and in 2013 an Italian team headed by Princeton Professor Naomi Leonard showed, using over 400 shots from video footage of the displays, that a “rule of seven” was the reason behind the movement: each individual bird’s movement was influenced by the seven nearest neighbours, and nothing else.

Seeking to match the direction and speed of their neighbours, starlings navigate the skies over our heads with startling ease, just by paying attention to each other.

Given a bird’s ability to see and react far quicker than us, these reactions are so mind-bogglingly rapid that when viewed as a whole, the impression given is a co-ordinated and rehearsed dark, brooding cloud of such stunning beauty that it’s hard to believe there are individuals in the midst of it taking their cue from just a handful of chums.

To our slow eyes, it also appears as if there are quicker and slower portions of the grouping, but it is now thought that they are all moving at the same rate: as we are watching a 3D display against the appearance of a 2D backdrop, the open sky, this illusion is created.

A word of warning, however: that’s a lot of birds up there, essentially getting ready for bed. If you do get the opportunity to witness one of these wonderful displays, wear a hat.

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