Starlings and their fascinating flight formations

Starlings fly in tight formation in Scotland's evening sky, forming a shape-shifting, cloud-like appearance — a true natural wonder. Usually, these birds flock together ahead of sundown before rapidly returning to the ground to rest.

These two starlings are fighting over food at Berlin's central train station — even though they are mostly sociable birds. In early summer, immediately after breeding season, young starlings begin forming groups. As autumn approaches, these groups grow larger and larger.

They tend to gather in very large flocks by September and October, as seen here in a small village in northern France, before migrating to southern and western Europe. Sometimes, these birds will fly up 2,000 kilometers (more than 1,200 miles) to reach milder climes.

Ornithologists say starlings gather into flocks primarily as a defense strategy against attacks by birds of prey. Faced with the dense formations, such as this flock over a field near Kiryat Gat, Israel, attackers hardly have any room to flap their wings — and ultimately fall out of the cloud.

It's thought that flying in such fluid, pulsating flocks prevents attackers from focusing on individual starlings. The same phenomenon can be observed underwater, where herring and other fish swim in tight schools.

Thanks to the bird's short wings and tail, the flock is easily able to adjust its flight path. Instead of following one leader, starlings in the Italian night sky simply adjust to the flight pattern of the few birds surrounding them.

Starling murmurations, as the swooping and swirling starling formations are called, can change directions in seconds. Starlings keep a distance of roughly one wingspan to other birds in the flock. But if one or several birds changes course, others will follow.

This well-timed photograph of a starling flock appearing to resemble the shape of a sperm whale was taken in southern Israel in 2015.

Rome sees scores of starlings arriving each year as temperatures drop in central and northern Europe. Flocks sometimes consist of 1 million birds, who produce considerable noise and unwelcome bird droppings as they pass overhead.

The Italian capital has launched a program to get rid of starlings in the city center and places like Termini railway station. In an attempt to clear the area, loudspeakers blast out artificial bird calls to chase the starlings away.

These impressively large starling formations in the sky are deceptive. In reality, starling numbers are dropping in Europe. This is because two of their main food sources, inland floodwater mosquitoes and marsh crane flies, are becoming increasingly rare with livestock now mainly held in stables, rather than in open fields.