ROME, Italy — Every sundown come fall, Rome residents witness an astounding spectacle, or, depending on how you see it, a scene out of an Alfred Hitchcock movie.
For a few hours after dusk, the sky above the city’s riverbank, piazzas and wealthy neighborhoods becomes plagued by thousands of European starlings zooming back and forth in fantastic tornado-like formations. Cacophonous calls echo throughout the city, as the dark-winged creatures soar through the air in sync.
“It’s very, very cool,” said Natalie Rozinova from Australia, as she covered her head with a map of Rome. “I don’t think I’ve ever seen that many birds in one spot, ever!”
But residents know better than to stop and stare. Rome’s pedestrians, along with roads, cars and monuments, soon become targets for a storm of droppings.
Besides complaints of a foul smell and rowdy nuisance, it turns out, starling excrement is a slippery street hazard. This has prompted the city of Rome to get rid of the spooky mob by beating them at their own game — scaring them out of the city.
“We recorded their cry for ‘danger, let’s leave!’ and we blasted it under their roosting sites,” said biologist Andrea Buscemi one evening as she walked along the Tiber River with a megaphone strapped to her back and an MP3 player hung over her shoulder.
“We wanted them to know that this isn’t a safe place for them to spend the night,” she said.
For the past three years, Buscemi and her crew of volunteer bird-busters have spent the month of November broadcasting these calls throughout the greenest neighborhoods in Rome.
Dressed in white surgical uniforms, the volunteers amplify the starling cry for three consecutive nights at a time in each location, hoping to shoo the birds out.
This scientific technique seems to work, at least for a while. But the European Starlings, which prefer nesting in urban and suburban areas, always return.
“We are sure that we’ll never manage to shoo them out of Rome completely,” said Buscemi. “We just want them to move a littler further away.”
These omnivores are native to Europe and have become infamous throughout the continent.
Traveling in flocks of thousands, the starlings migrate to southern Europe in the winter and feed on almost anything, including fruit and olive orchards, destroying local crops in the process.
Known for their aggressiveness, the second-cavity nesters are outnumbering local bird species, as they are able to lay triple clutches of their pale blue eggs in only one mating season.
They have been nominated as one of the “100 worst world invaders” by the Invasive Species Specialist Group, for the threat they pose to biodiversity and agriculture.
The European starling’s fertile advantage is what helped them spread rapidly throughout North America in the last century.
In New York’s Central Park, the first 100 starlings were released in 1890 in an attempt to bring to America all the birds from William Shakespeare’s plays. The English playwright mentions the starling in one passage of “Henry IV.” Since that first release, the dark, pudgy bird has flourished into the millions in the U.S. and is considered a nuisance in the greener cities it flocks to the most.
EU governments have been trying to get rid of the starlings for decades — shooting them, poisoning them and even bombing them — without much success.
In Rome, the city’s only feasible strategy was to trick them. But as the local government takes pride in the idea of outsmarting the starlings, some researchers who live in the eternal city believe that science has a lot to learn from starling flock behavior.
“When starlings are under attack, they actually enhance their coordination and achieve a better global coordination of the flock,” said physicist Andrea Cavagna, who leads a EU-funded project on the starlings.
“This is the opposite of what happens for humans,” he said.
Cavagna’s research group, “Starflag,” is the first of its kind. As statistical physicists they have mapped out the movement of thousands of birds and converted them into mathematical equations.
From these formulas, Cavagna says he envisions a new generation of adroit technology that can produce split-second responses to emergency situations — like starling flocks do with falcon attacks.
The shooing of starlings from the city this fall won’t stop the researchers. Nor will it keep the starlings from returning next year.