Researchers explain impossibly choreographed starling flights
For the record, a flock of European starlings is called a murmuration.
And if you are lucky enough to witness one in flight, you'll likely never forget this aerial dance.
When hundreds or thousands of these birds take off from a roosting spot, they can form what resembles massive black clouds that shift shapes, rippling and twisting in the sky.
These performances seem impossibly choreographed and synchronized, birds communicating in a split second to dart here, there and everywhere as one.
But these murmurations are not just for show.
"Any time you see a large aggregation of animals, it's usually anti-predator (behavior) or food finding," said Kevin McGowan, a researcher at the Cornell Lab of Ornithology in Ithaca, N.Y.
"For a little bird like starlings, they're finding safety in numbers."
European starlings are an invasive, non-native species in the United States. In the 1890s, a group of Shakespeare enthusiasts released about 100 of the birds in New York's Central Park, according to the Cornell lab.
The group hoped to introduce to North America every bird mentioned in Shakespeare's plays. Although the starling was referenced just once in Shakespeare's Henry IV, more than 200 million descendents of those first birds now take flight across North America, according to the lab. An estimated 2.6 million call Ohio home.
In the United States, the birds haven't exactly received a warm welcome. Starlings eat just about anything, and their love for crops makes them an enemy of farmers.
All of that food makes them prolific poopers, often covering our cars, said Jim McCormac, a wildlife expert with the Ohio Department of Natural Resources. Starlings also displace native cavity-nesting birds, including bluebirds and woodpeckers, by stealing their holes in trees, he said.
Then again, predators such as falcons love them. One on one, anyway. But when a group of starlings takes to the sky as one in a defensive formation, things change.
A 2011 study by a team of Italian researchers found a correlation between the aerial formations and a reduced success rate of predator attacks.
Two years later, Princeton University professor Naomi Leonard and several colleagues conducted another study to research how massive flocks maneuver in unison.
It turns out that the birds react to the movements of their closest neighbors in the murmuration, Leonard said.
"We were able to show that six or seven neighbors per bird did sort of an efficient management of uncertainty in the sense that it wouldn't pay off for them to pay attention to more neighbors," she said.
The formation starts taking shape when the birds closest to the predator spot the threat and alert their neighbors with an alarm call or by accelerating, according to the 2011 study. As more birds are alerted, a wave ripples through the flock, traveling away from the threat.
McGowan said the wave is driven by every bird trying to get away from the predator as fast as possible.
"There's no captain here," he said. "There's nobody shouting, 'company left.' There's sort of a group decision-making that goes on that we're still investigating."
The defensive tactic confuses predators by making it difficult to pick out a single target, McGowan said. Schools of fish and a handful of other birds use similar defensive formations.
Despite the starlings' shortcomings, those displays make them irresistible to bird-watchers.
"When you see these formations, it's worth just stopping and saying, 'Wow, that's pretty cool,' " McGowan said.
