MIAMI — Over the last few years, staff members at Everglades National Park have experimented with ways to scare off flocks of vandals that lurk in parking lots every winter, sporadically defacing cars, trucks and boat trailers.
They’ve tried yelling at them, squirting them with water, even dangling dead ones upside down in trees.
But nothing has curbed the curious appetite that migrating vultures have developed for windshield wipers, sunroof seals and other rubber and vinyl vehicle parts. So this winter, the park is shifting to purely defensive tactics against the big birds, expanding a program that provides visitors at the most trouble-prone sites loaner “anti-vulture kits” consisting of blue plastic tarps and bungee cords.
“It’s recognition on our part that they’re part of the park and we’re the intruders in their world,” said park wildlife biologist Skip Snow. “The vultures are doing what comes naturally.”
Naturally, as in flying south for the winter and congregating in the Everglades. The car-munching, on the other hand, is a departure from the normal diet of the dead and decaying and a habit that largely perplexes scientists.
The birds, usually black vultures native to the Southeast that swell the year-round resident buzzard population during cold months, can be found many mornings perched on cars or trucks at Anhinga Trail, the park’s first and most popular tourist stop, or in Flamingo, an isolated outpost on Florida Bay. Much of the time they do little or no damage but once they get going, the destruction can sometimes be extensive, shocking even experienced Glades hands.
Adam Gelber, a consulting biologist and frequent Everglades angler, found that out early this winter when he took visiting scientists from California on a scenic tour of park waters, finding rare crocodiles, bald eagles and wake-riding dolphins.
“It was a National Geographic kind of day in the park,” Gelber said.
At least until he walked back to the Flamingo boat ramp. Vulture dung covered the hood of his GMC Yukon. Worse, just about every piece of rubber and plastic on his sunroof, windows and hood was ripped away and shredded. The insurance company paid $1,850 for the damage, he said — and that was before he discovered the birds had also apparently yanked out the seals on the bottom of the doors as well.
“It took the guys from the insurance agency 10 or 15 minutes to even figure out how to code it,” said Gelber, who has since decided to invest in his own anti-vulture kit.
The park’s vulture problems are certainly odd but they’re not unique.
Though known primarily as scavengers, vultures have caused similar problems in many states, attacking a wide variety of materials from roof shingles to pool screens. Scientists have studied the behavior for years and developed some tactics for discouraging it, but they can still only speculate on what whets the birds’ appetites.
“Exactly why they do it or when they do it or why they choose one vehicle over another, any reasons for that are pretty much unknown,” Snow said.
A variety of theories have been debunked. One is that rubber releases an aroma that attracts the birds, possibly from some chemical or other ingredient in the material, such as fish oil. But experiments with various emissions from the stuff that goes into car parts have provided no clear answers and the black vultures, biologists say, don’t have a great sense of smell anyway — which is probably good, given the dead and rotting meat they typically consume.
Another, more plausible theory is that the naturally social and curious birds may simply be sampling available fare as they pass time in the morning hanging out, waiting to warm up and take to the air to forage. Or it could be young birds engaging in ritualistic feeding behavior.
One thing does seem clear: The birds aren’t nibbling because they’re hungry. They rip the rubber from vehicles but typically discard it, eating little or any of the material.
One recent morning, several dozen vultures lolled in the Flamingo lot, perching in small groups on a handful of trucks and trailers — including one protected by a billowing blue tarp — but utterly ignoring other vehicles. On this morning, none seemed particularly rapacious, absently pecking now and then at a hard vinyl around a pickup window or worn carpet on trailer bunks. A few squabbled over a two-foot strip of weather seal in the parking lot.
After a daylong outing in the Everglades backcountry, Matthew Seeburger of Plantation was shocked to see photos of his truck and boat trailer adorned with a half-dozen vultures. They’d done little, thankfully, other than peck at the carpet on the boat trailer.
“Wow, that’s what was going on while I was gone?” he asked. “Now that I see this, I should probably get a tarp myself.”
Though most vehicles escape any damage, Gelber and others can attest to the heavy price if the birds take a fancy to an unattended car. More than a few videos also posted on YouTube show vultures in the Everglades going to town on cars and trucks, including one series capturing a small group shredding a rental recreational vehicle roof like it was carrion.
After complaints increased from visitors, the park posted warning signs a few years back and began consulting with federal wildlife experts to try to develop methods to break the car habit. But the options were limited for a protected species that naturally occurs in a national park.
“Harassment” techniques like making noise or squirting water are too time-consuming and disruptive and work only for short periods. A dumpster near the fish-cleaning station in Flamingo that seemed to be attracting the birds was moved farther from the parking lot. The most startling tactic, tried in 2010: effigy birds, road-kill vultures dangled from trees near Anhinga Trail.
The results, said Snow, were mixed. They disrupted the birds for a few weeks but the carcasses grew gamey, required frequent replacement and also disturbed some visitors.
In the long run, said Snow, there proved to be no cheap or easy solutions to changing the habits of birds, so the park decided to instead ask visitors to adapt to the vultures. Park Superintendent Dan Kimball said complaints have declined since the loaner tarps were distributed at Anhinga Trail in 2011 and expanded to Flamingo this winter.
The kits are intended mainly for occasional visitors, who are asked to return the tarps and bungees when they leave the parking lot. Regulars, like Flamingo anglers, are advised to buy their own better-fitting covers. So far, Kimball said, the park hasn’t lost a single tarp. Once the weather warms, and the vulture population thins out as many head north, the risks dwindle.
Snow acknowledged that many visitors might view the vultures as ugly nuisances in a park filled with elegant wading birds and soaring ospreys and eagles but “they are indeed a useful part of the ecosystem and we certainly want them around as much as any other bird.”
Victor Lugo, a maintenance worker at Flamingo, said he has come to appreciate the role they serve. When an alligator was killed along the main road a few months ago, he pulled it off the road and nature’s clean-up crew quickly took over.
“Within two days, they’d picked him clean from the inside,” he said. “These are the cleanest roads in America.”