Paolo Patrizi Photographer

Many thousands of birds wheeling through the sky above Rome at sunset prepare to roost together for the night, providing both breathtaking aerial displays and a public nuisance in the form of noise and bird droppings. A starling flock like this is called a 'murmuration', a word that perfectly describes the rustle of thousands of pairs of wings.
The coordinated evolutions of large flocks of starlings at dusk represent one of the great wonders of nature. These flocks remain incredibly cohesive under attack by predators, never leaving a bird isolated. When attacked, the birds spread apart; conversely, when the flock makes a directional change, they merge closer together. Throughout these incredible manoeuvres, individual birds always remain integrated with the flock, no matter how drastically the group's shape and intensity changes.
Remarkably, after an attack forces the flock to expand, it can regroup quickly because cohesion does not depend on the distance between birds. Instead, interaction is based upon the number of neighbouring birds rather than their distance apart, which implies complex cognitive capabilities in these creatures. These findings may have implications for understanding other animal groups and even human behaviour. The birds' behaviour could mirror the herding responses seen in human beings—with particular relevance to stock-market panics. Just as starlings coordinate with their neighbours, individual people imitate each other to create collective phenomena, strongly influenced by their neighbours, fashions, and fads.

"Rome in winter, shortly before dusk, means one thing: wheeling, elegant flocks of starlings – murmurations – performing extraordinary aerial ballets that, from a distance, look like ink smudges” The Guardian