The starling is a medium-sized bird of the Sturnidae family. It is found in Europe, Asia and Africa. During winters, starlings arrive in several flocks above a (usually communal) roosting site which coalesces into a swirling mass of birds that twists and turns through the air. The various shapes these swarms make in the air are known as murmurations. It is believed that they are formed to help evade attacks from birds of prey. Pictured here is a murmuration in the Welsh town of Aberystwyth.Once the birds know that there is no danger, they break off from the main group in coordinated descents. This is a murmuration in the Potteric Carr Nature Reserve in Yorkshire, England.According to scientists, the change in the behavioural state of one bird affects and is affected by that of all other birds in the group, no matter how large the group is. Physicists call it ‘scale-free correlation’. This is how a huge murmuration is able to respond to a predator attack as effectively and fluidly as a small flock. Pictured here is a murmuration in Rome, Italy.