ROME — There is nothing quite as overpowering as the acidic stench of the fresh, wet feces from more than 4 million birds that have apparently decided to winter in Rome this year.

The sickly sweet smell, which is unavoidable in much of the center of Rome, is accompanied by a slick sheen of sh*t covering everything from sidewalks and cobblestones to churches, park benches, and café tables. And it is more than just an annoyance. It has become a death trap causing scores of car and moped accidents and nearly 100 fractures and sprains attributed to pedestrians falling on the slippery stuff.

The crisis, which has been brewing for more than a month, came to a head over the weekend, when the first serious winter rains fell on the Italian capital, making the gluey guano even more treacherous. The city of Rome even closed the busy thoroughfare that runs along the Tiber River for more than 10 hours so crews could sand and scrape the slime after more than a dozen accidents were reported in less than an hour as scooters slid and pedestrians plummeted to the pavement.

The messy birds are European Starlings, which always make their mark on Rome as they migrate through the capital in the late fall months on their way to warmer climes. They spend their days gorging on the remains of fresh olives in the hinterland outside of Rome and come to the warmer city to nest at night in the trees along the Tiber River that runs through the city.

During the late-afternoon hours, they put on a mesmerizing, magical synchronized show over the city as they swarm in uniform. Then they bed down in the city’s trees and digest their olives, dropping their rain of terror onto the streets—and anyone on them—below.

Roman residents know all too well to carry umbrellas and not park for long on tree-lined streets during the starling season. But this year, for a variety of reasons, the busy birds have not moved on and their flock has grown from the usual million or so to an estimated 4 million, which has turned their nightly show into something more of an Alfred Hitchcock horror film, as they often collide and come tumbling down in a thud on the busy streets.

The reason the birds are so bad this year has been blamed on everything from global warming with unseasonably warm winter temperatures to the Mafia Capitale scandal under which the city of Rome has been bilked for decades. The theory goes that as the city tried to clean up its coffers, valuable contracts for secondary services like bird chasing slipped through the cracks, leading to what is seen as a largely “too little-too late” approach to the problem.

The city is without a mayor at the moment, and the last time the city council met to discuss non-essential matters was Oct. 30. “It’s an embarrassment,” says Fabrizio Ghera, a former city council member who had apparently warned the interim city government that they’d better act fast or the, uh, excrement would hit the fan. “We are a world class capital in the midst of a Holy Jubilee and the tourists are covered in crap,” he said.

The strong Green Party in Italy has also been blamed since years ago they were able to get the city to vow never to engage in mass poisoning or outright hunting of the feathered pests for population control—no matter how deep the city was in fecal matter.

Since November, the city of Rome has spent more than $45,000 on more than 60 attempts to scare away the birds, including a bizarre plan to enlist five Harris hawks named Cami, Niky, Gimmy, Giorgio e Angela that originally hailed from Texas to hunt the birds, which proved unsuccessful after the predatory birds, overwhelmed by the size of the flock, gave up and flew the coop.

The city then found the budget it had previously cut when cleaning up the Mafia Capitale mess to reinstate the marginally successful and incredibly annoying “birdmen” loudspeaker system, whereby agents in hazmat suits carrying megaphones and bullhorns blast the sound of screeching predator birds under the nesting birds to scare them away. This system has historically chased most of the birds away within a few weeks of their arrival, but because the city is administratively challenged in the absence of a mayor, no one got around to calling in the experts in time this year. And because the city only decided late to spend the $20,000 for the speaker screeching, it hasn’t been much help yet, since the bird population has been multiplying fast.

But it may just be Mother Nature who solves the problems. On Saturday night, temperatures in Rome finally dropped to seasonal lows and the Fauna Urbus city environmental agency, which runs the speaker scare program, promised the birds would soon be on the move. “They’ve started making their way further south,” Alessandra Bruscemi, head of the group said. “But because we started so late, we may be chasing the birds away until March.”

In the meantime, Roman residents have little to do but sit around and wait, and wade through the mess.