The described scenes of Indiana farmlands and elsewhere seem like they’ve jumped from a page in a horror novel, with black vultures descending into the woods and meadows of the Midwest and beyond.
Farmers tell of relentless attacks on their animals: the wake of large black forehead birds, feeding on newborn calves as they emerge from their mothers, and sometimes preying on the mothers themselves.
“In the last few years, they’ve become very aggressive,” said John Hardin, a rancher in Scott County in southern Indiana, about 20 miles north of Louisville, Ky., who often sees eight to 10 of the birds on his farm. . At least two of his calves have been killed by vultures, maybe more. “They love the navel area and they’ll take it all the way to the bone and hide.”
Vultures are often referred to as “nature’s garbage disposal” because their highly modified digestive systems and immune systems allow them to eat dead and diseased carcasses with impunity. Though scavenger is considered a vital ecosystem service, reports of black vultures preying on live animals are relatively unheard of, some experts say, with some expressing skepticism that predation is actually taking place.
The situation in Indiana this summer proved alarming enough that farmers can now quickly obtain permits — obtained from the US Fish and Wildlife Service through the Indiana Farm Bureau — to “capture” or kill up to three birds, a new program in effect. in other Midwestern states.
“These migratory birds are crossing the Ohio River,” said Greg Slipher, a livestock specialist at the Indiana Farm Bureau. “I got a warning from my counterpart in Kentucky, and he said, ‘They’re coming your way’ and he was right. In the last three or four years we have gone from a few reported incidents to many.”
Much is still unknown about the bird and why its numbers are growing in states where they were unseen a decade ago. They were traditionally found in the southern United States and Central and South America, and it is unclear why they significantly expanded their range north and west. Some speculate that milder winters due to climate change may be a factor.
From 2007 to 2019, black vulture breeding populations increased by one percent to four percent annually across the species’ range in the United States, excluding small areas of the Gulf Coast and South Central Florida, according to an eBird analysis. data by the Cornell Lab of Ornithology.
The extent of predation by black vultures is far from established as they have moved to new territory. One of the country’s leading ornithologists is highly skeptical and has expressed concern about the permits granted to kill them. Black vultures are one of approximately 1,100 species protected under the age-old International Migratory Bird Treaty Act; harming them without permits can lead to heavy fines or even jail time.
“I’m going to take an extreme stance here and say they don’t kill healthy calves,” said John W. Fitzpatrick, the recently retired director of the Cornell Lab of Ornithology in Ithaca, New York.
For seven years, he ran the Archbold Biological Station in Central Florida, which includes a working cattle ranch home to black vultures. “They are often seen around calves in problems that are stillborn or dying and they jump on it quickly,” he said. But, he added, “the idea that they are predatory on livestock is false.”
“In my opinion, it should be considered lore because it is not well documented,” he said. The vultures may occasionally attack a healthy calf, he said. But, “are we really talking about something so ubiquitous and economically destructive that we have to allow the destruction of a protected bird?”
The vultures are large birds, weighing nearly five pounds, covered in what appears to be a helmet of gray featherless skin. They have a large wingspan of up to five feet, which provides loft as they fly on thermals and spot prey. They are one of three species of vulture in the US; the turkey vulture and the endangered California condor are the other two.
“The black vulture is an amazing bird,” said Dr. Fitzpatrick. “They are faithfully mated, have great and complex social behavior and are super smart. They guard the nest well. The eggs hatch and become these fluffy white chicks, and over a month or six weeks you can always find out that one nest is nearby, because one of them is sitting in the same place day after day, week after week.”
dr. Grant Burcham is a veterinary diagnostician at the Heeke Animal Disease Diagnostic Laboratory at Purdue University, which owns a research livestock farm.
dr. Burcham said he received a calf killed by vultures and euthanized two others who were attacked. Autopsies showed the calves were not healthy — two had “scabies,” an intestinal disease, and the third a broken leg — and possibly selected by vultures sensing their vulnerability. “The animals were dehydrated and would have been visibly sluggish, which is why they were presumably targeted.”
A recent paper concluded that the incidence of scavenger predation in Argentina, including the black vulture, while considered frequent, was not common at all.
Patrick Zollner, a professor of ecology at Purdue University, agreed that empirical evidence for predation was lacking. “What’s totally unknown in Indiana and most places is how often this happens,” he wrote in an email. “Addressing that gap is one of the goals of our ongoing research.”
Marian Wahl, a doctoral student with Dr. Zollner at Purdue, who studies the birds in Indiana, said she believed there were several million black vultures in the United States, and in Indiana from just a few decades ago to about 17,000 now.
While the U.S. Fish and Wildlife Service can issue special permits to kill birds that cause harm, the process of obtaining them can be lengthy and cumbersome, costing $100 each. The relatively new program in Indiana and elsewhere allows state farms to obtain a large number of permits and issue sub-licenses, which experts say is more responsive.
Mr Slipher said he has received 45 requests for “take” permits and authorized 22 since the program went into effect in early August.
While the permits allow each person to shoot three birds, Mr. Slipher says there is a better strategy.
“I advise, don’t go out and shoot all three on the first day,” he said. “One of the things we know about this particular species is that they respond substantially to effigies of their own species. We encourage our producers to shoot that first bird and hang that bird in effigy.”
It’s an approach that has helped the hardest hit producers in Kentucky — somewhat. While real and fake hanging effigies are widely used to propagate the birds, and there are studies showing they work, their effectiveness is not well understood.
“If you use an effigy to spread out a roost, does that keep them away from livestock or do they just go to a roost further down the road and keep going back to the same farm?” asked Mrs. Wahl.
Joe Cain, of the Kentucky Farm Bureau, said the black vultures started showing up in his state in the early 2000s and that Kentucky had started in 2015 with the new licensing system that had just been instituted in Indiana.
“We’re only hitting the hot spots,” Mr. Cain said. “The ones with the biggest problems are the ones who call us. There are many more people who see predators, but at least they know there is a program to help them protect their livestock.”
The permits have not significantly reduced the number of cattle killed, officials said. In Kentucky, about 500 to 600 cows are killed each year, they noted, adding that more lambs, goats, free-range chickens and turkeys have been cut as vulture populations increase.
Other tactics include making loud noises with devices such as propane cannons, firing fireworks, spraying the birds with high-pressure hoses, and using guard dogs. Since the vultures often sleep in large dead trees to survey the landscape and look for prey, cutting down those trees can also provide relief. The efficacy of these measures is part of the research conducted by Ms Wahl and Dr Zollner.
mr. Cain would like to see federal law changed to help farmers. “We have asked Congress for a safe harbor facility,” he said. “If they see looting taking place, it’s unreasonable to say, ‘I’m going to go back home and apply for a permit and wait two days before I get the permit.’ If they see it happening, it makes much more sense to protect your livestock.”
A vulture’s attack on live prey is a grim scenario, farmers say. “The birds come in during birth – essentially at the most vulnerable time,” Mr Slipher said. “Literally when the calf is on its way out of its mother, we get black vultures attacking the calf and attacking the mother.”
The bird often plucks the eyes, nose, mouth and navel. Farmers say every animal that dies is valued at $1,000.
They’re a nuisance for other reasons too: They rip asphalt shingles off homes, tear windshield wipers and rubber seals around vehicle sunroofs, and tear seat covers on farm machinery and boats.
Their stomach acid is almost as corrosive as battery acid, and their feces, urine and vomit can eat away at rooftops, towers and other places where they sleep.
But vultures are also a proven and crucial part of the ecosystem. In India, for example, massive deaths of vultures have occurred due to the widespread use of a veterinary drug that is toxic to the birds. That led to an increase in rabies. Vultures used to clear up dead livestock and other waste; when they disappeared, dogs started feeding on the waste, and as their numbers increased, so did the incidence of rabies.