What is a murmuration? And why do Starlings do it?
‘Murmurations’ are the astounding aerial ballet that Starlings perform outside of the breeding season, in the autumn and winter.
Starling murmurations begin to form in November, though this varies from site to site, and some can begin as early as September. More and more birds will flock together as the weeks go on, and in some places the number of Starlings in a roost can swell to about 100,000 or more.
As the sun starts to fall the birds will all gather around their roosting spot, forming a huge close-knit flock that moves in the air like a shoal of fish. From the ground, it looks as if the flock is shape-shifting – waving and twisting in perfect unison. With the orange sky and chill air, it truly is a special experience.
For a long time, it wasn’t known how they move in such perfect synchrony – some scientists back in the 1930s even thought murmurations were evidence that some birds have psychic powers. Now we know that each individual Starling is following three simple rules: 1. Don’t crash, 2. follow the direction of your neighbours, and 3. stay close to your neighbours. Each Starling applies these rules to their seven closest neighbours and, since they’re following their seven closest neighbours in turn, the whole flock moves seemingly as one.
It turns out these simple rules apply to a lot of other big swarms of living things, whether fish or insect. They’ve even been applied in animation and film-making – animators created the swarm of bats in Tim Burton’s Batman Returns and the stampeding wildebeest in the original The Lion King using these principles.
As to why Starlings do this in the first place, that is a bit less certain. It is thought that they group together to seek safety in numbers from predators such as Peregrines – it’s hard to target just one bird in a flock of hundreds, or even thousands. Starlings also gather at night to keep warm, so a murmuration is a way for all Starlings to come together before roosting. Once the birds are satisfied that the coast is clear, birds will peel off from the main group in coordinated descents, settling into the roost with a loud flurry of wings and chattering – a spectacle in itself.