Lasers, cannons, effigies: The surprising science of shooing vultures away

As hundreds of vultures flock to an Alabama school, many have wondered: How to scare off the birds? Science has an answer.

For several months, a flock of more than a hundred black vultures has settled atop Opelika Middle School in east Alabama. They peer down at students as they arrive, soar in lazy spirals over soccer practice, and streak the field’s floodlights with feces.

Despite administrators’ best efforts, the birds keep coming back, unnerving some students who have to walk past a gauntlet of vultures every day.

In response to a nuisance report from the school superintendent, a local U.S. Department of Agriculture representative recommended shooting several of the birds and hanging their corpses upside-down in nearby trees. These “effigies” swinging in the wind should serve as a warning to the rest of the flock to steer clear, the USDA representative said, according to a memo from Opelika Mayor Gary Fuller.

Community members balked, pointing out that the birds play an important ecological role in the disposal of dead animals and pose no threat to students. Some even like the vultures being around. Others argue there must be a less grisly way to get the scavengers to disperse.

And the science backs them up. Since the early 2000s, researchers have developed an arsenal—more like a toybox, really—of tools to humanely encourage vultures to move along. It’s dramatic fare, from fireworks and air cannons to lasers. Welcome to the whimsical world of vulture dispersal.

Nature’s dirty work

Two species of vultures are largely responsible for cleaning up North America’s dead animals—the mild-mannered turkey vulture and its rascally cousin the black vulture. As scavengers, they’re like stinky “little Buddhists of the sky,” says Amanda Holland, an independent wildlife biologist and unabashed vulture fan. “They don’t kill much, if anything at all.”

And they’re clean, despite their carrion-eating ways and charming habit of expelling putrid-smelling vomit when they feel threatened. A vulture’s stomach is a roiling acid bath, neutralizing pathogens the birds ingest as they scarf down roadkill and predators’ leftovers. Vultures are immune to leprosy, cholera, and anthrax, and they are essential for preventing the spread of carcass-borne diseases.

The bigger nuisance, to some humans, is the property damage. Black vultures, which gather in groups of anywhere from 25 to 400 birds, seek out tall structures to perch upon, like towers, buildings, and transmission lines. Turkey vultures sometimes join the flock too. The high acid content of their droppings can corrode metals over time and lead to power outages at electrical transmission towers, according to the USDA.

Their curiosity can also get them into trouble, Holland says. Common vulture mischief includes peeling off shingles, stripping caulking from windows, liberally redistributing the contents of trash cans, and yanking the rubber off windshield wipers. They also have a peculiar zeal for tearing up vinyl-like plastics.

Despite their antics, there’s a lot to love, Holland says. “When they pick up a thermal, especially on a really good windy day…They just look like they’re having the time of their life up there.”

Razzle-dazzle ‘em

Vultures are protected in the U.S. by the Migratory Bird Treaty Act, which makes it illegal to harass or kill them, even on private property. Violators can face penalties of up to $15,000 and six months in prison.

Obtaining a special nuisance permit from the USDA opens up a range of options to legally harass the birds, however, including shooting a few to make effigies.

Effigies have been popular among USDA wildlife managers since 1999, when researchers first piloted freeze-dried turkey vulture carcasses as a dispersal agent in Ohio. In one field study, vulture populations at communication towers shrank by over 90 percent within days of an effigy’s installation and stayed low for months after it was removed.

But effigies aren’t a silver bullet, especially when it comes to black vultures, says Bryan Kluever, a biologist at the USDA who studies interactions between humans and wildlife. In 2012, a Florida early childhood education center hung three vulture carcasses in trees in hopes of banishing an unwelcome flock of hundreds of black vultures. The birds stayed put, which wasn’t exactly shocking to researchers who had watched the group devour the carcasses of other vultures that died on the property.

“Any sort of hanging disturbance can suddenly become sort of an attractant or enrichment toy,” says Bracken Brown, a wildlife biologist at Hawk Mountain Sanctuary in Pennsylvania who’s tracked vultures across the U.S. for more than a decade. Vultures are so inquisitive, he says, it’s a constant push and pull between what the birds might find scary and what they’ll want to investigate.

Some wildlife managers swear by “evil-eye balloons,” helium-filled mylar painted with giant eyespots invoking some behemoth predator. But other managers just laugh and share pictures of vultures nibbling on the balloons.

Motion-activated sprinklers have proven effective on roofs and boat docks. But too much water can create a pool that vultures find perfect for splashing and sipping.

Lasers, another USDA standard, do work as long as someone’s willing to stand there and trace the light around each vulture’s feet, one by one. When vultures are gathered in large flocks, sometimes called committees, that’s a laborious process.

Pyrotechnics—“flashers” and “bangers” fired from specialized pistols—can also work, but they have to be set off often. They’re an airport favorite, standard issue at Hartsfield-Jackson in Atlanta, the world’s busiest airport.

In December, a North Carolina high school mounted a propane cannon on its roof to shoo away dozens of vultures. Propane cannons boom at 130 decibels, about as loud as standing next to an ambulance’s siren. After repeated use the vultures left, “although they didn’t seem to move far,” says Kristy Woods, a math teacher at the school. “Apparently they have decided to hang around the local Subway.”

Vultures are creatures of habit, Brown emphasizes, so it’s important to disrupt their routine before it solidifies. Remove any attractants, such as unsecured garbage or pet food, and go about your business loudly around roosting time.

This month, government scientists also plan to start testing tube men, those flailing balloon guys often used at car dealerships.

Currently, the USDA recommends a multi-sensory shock-and-awe campaign to disperse vultures, at least when initial efforts don’t work. Such a multi-pronged effort is employed at the Gainesville Regional Airport, which uses air cannons, anti-perching devices, and an effigy.

“Our biggest success continues to be the effigy,” says Shaun Blevins, the airport’s operations manager and veteran vulture-discourager. It’s a single taxidermy vulture dangling from an antenna in the middle of the airfield, replaced yearly at a cost of about $300, he says.

That’s a bargain since black vulture strikes were responsible for more than $120 million in damage to aircraft from 2010 to 2019 in the United States, according to the Federal Aviation Administration.

The future of vulture dispersal—and vultures

Conservationists hope that efforts to rebrand vultures from ominous to essential will make people more willing to coexist. While populations of black and turkey vultures are climbing in North America, their scavenging relatives are threatened or endangered in much of the world.

Removing vultures from an ecosystem can lead to disaster. In India, for example, more than 95 percent of the vulture population has been wiped out through accidental poisoning by a veterinary drug in cow carcasses. Feral dogs and rats stepped in to fill the carrion-eating void, leading to a surge in human rabies cases. (Learn more: Here’s why we need to save vultures.)

Rebranding efforts, in Opelika at least, seem to be working. Many credit the Southeastern Raptor Center, in nearby Auburn, with helping locals see the oft-maligned species in a new light.

“After meeting our raptor ambassadors, perceptions about vultures change quickly,” says Andrew Hopkins, an educator at the center, which cares for birds like Melvin, a black vulture who imprinted on humans as a chick. Melvin loves solving puzzles for treats, and despite his five-foot wingspan, only weighs four pounds.

Fuller, Opelika’s mayor, says he plans to meet this week with local USDA wildlife managers to discuss non-lethal—and less grisly—tactics. “The overwhelming number of folks that I’ve heard from don’t want us shooting any vultures.”

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