Starling murmuration ... sounds like a song doesn’t it? The reality is just as lovely as you would imagine.

Starlings are small- to medium-size birds that have a short tail and a pointed head with glossy black feathers streaked with hints of purple and green. In large numbers, starlings can create a “murmuration” when huge groups of these birds gather together, moving in one large mass across the sky. They don’t simply fly in a flock. They twist and turn into all different shapes during this sky show.

Experts aren’t exactly sure how, but a murmuration forms when one starling copies the behavior of its seven neighbors, and then those nearby starlings copy each of their seven neighbors, and so on until the entire group moves as one.1

Why Starling Murmurations Form?

Maybe the best comparison for this “celestial strangeness” is a school of fish moving as one in the ocean to avoid a predator. The fish dart rapidly from one direction to the next to distract and tire their predators. A starling murmuration works in much the same way. Starlings produce a synchronized cloud of movement over their chosen roosting site. A roost is where they will rest as a group for the night, which is why murmurations occur most often at sundown.2

Scientists hypothesize that starlings use their choreographed dance to deter larger predators like hawks or falcons from attacking the group. Moving as one not only confuses the predator but also decreases the individual risk each starling faces.3

Another hypothesis centers on body heat. A murmuration can attract other starlings in the area to one central roosting site. Especially in the colder months, more starlings congregated together creates a warmer roosting spot.3 However, roosts are usually largest in the late summer, when a starling group can reach 100,000 or more.45

Scientists have also proposed starlings assemble together to share information about their environment for feeding purposes. This “information center” hypothesis rests on an evolutionary idea that when food is difficult to find, a species must rely on a free sharing of information to survive.

A study published in the Proceedings of the National Academy of Sciences in 2010 attempted to explain this incredible phenomenon with physics, citing “scale-free correlation” and synchronization caused by sound as the source behind starlings’ such coordinated movements.6

The scientists who authored the study applied velocity and the physics of magnetism to murmuration groups, observing that birds move in similar ways to how electrons move when nearby particles become magnetized.6

These are hypotheses, however, and despite applying the latest technology, the reason and methods driving murmurations have continued to stump biologists, physicists, engineers, and mathematicians.

The starling flocks move as one large being and not one single bird is responsible for the murmuration’s movement.7

When and Where Do Starling Murmurations Occur?

While starling murmurations occur most often in the United Kingdom, starling numbers have grown tremendously in the United States after its purposeful introduction into the country in the late 1800s by Shakespeare fans (even though starlings are mentioned only once in Shakespeare’s entire portfolio: Henry IV, Act 1).

It is estimated that 150 million starlings currently reside in the United States, bringing with them their “black sun.”4 Many Americans consider this species a pest, however, due to its growing presence.

Though these birds will separate into small groups to feed, most swarm back together at sundown to participate in the murmuration. The name for this activity comes from the sound starlings’ wings make when thousands are fluttering together in one large liquid mass.