MAPLETON, Iowa — In cowboy movies and TV shows, the sight of vultures circling overhead usually is a sign of doom and despair.
For residents of some Siouxland communities, feces and vomit might come to mind instead.
Due to growing populations, turkey vultures are coming into closer proximity to humans, and it’s not always a pleasant interaction, as Mapleton Mayor Brent Streck can tell you.
A group of 15-20 turkey vultures has taken a liking to a cell tower near the cemetery on the southeast side of town, but that’s not the problem. The vultures fly into town to visit a couple favorite trees, where they roost and then defecate and vomit, causing a mess and potentially damaging paint on vehicles and houses.
“Nobody cares if they’d just fly around town. It’s what they create and leave behind that’s the issue,” Streck said.
Other communities face similar issues with flocks of the scavengers perching in or near town.
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With their big, black bodies and bright red, featherless heads, vultures face an image problem, no matter how beneficial they are in nature.
“You look at the bird, and it’s understandable,” Iowa Department of Natural Resources wildlife biologist Andy Kellner said. “The image of a large, black bird with their wings spread out, it’s an appearance factor which is just unfortunate for the bird.”
It is unfortunate, considering how much good vultures do.
Using their highly developed sense of smell to locate food, turkey vultures clean up the ecosystem by eating dead animals. In doing so, they reduce the spread of illness and disease.
Humans look past those benefits when their property is covered in vulture droppings. If that’s not bad enough, vultures vomit when scared or feeling threatened. Filled with acidic digestive juices, the vomit stinks, a means of defense to drive away predators.
“It’s good to have them around, but understandable you wouldn’t want them roosting over your garage or a public building,” Kellner said.
The use of DDT and other pesticides in the 1960s and ’70s decimated vulture and other raptor species populations, Kellner said. Since the ban of many of those chemicals, bird populations have slowly recovered over decades, leading to growing numbers and closer contact with humans.
Old-growth timber with its tall trees is declining, Kellner said, forcing the social birds to find other perches large enough to hold a whole group and also tall enough to provide safe views of any approaching predators. It’s why cell towers and water towers attract them.
Turkey vultures return to the same nesting site, often in remote areas, year after year. Meanwhile, the juvenile vultures congregate elsewhere and cause many of the problems. Vulture-related calls to the DNR’s depredation program, which deals with conflicts between wildlife and humans, have increased in the past 15 years, Kellner said.
Noisemakers such as fireworks can scare a flock of vultures away, Kellner said. They don’t like to get wet, so spraying them with water might drive them off. Hanging a dead turkey vulture — or a large bird decoy painted to look like one — upside down near a roosting site also can be an effective deterrent.
If that doesn’t work, community leaders may opt for lethal options. Like many migratory birds, turkey vultures are protected under the federal Migratory Bird Treaty Act. It’s illegal to kill them without a permit from the Wildlife Services division of the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service.
Shooting just one or two vultures might be enough to scare away a flock, Kellner said.
The city of Mapleton has obtained a permit for the past three years after first trying other scare tactics. Streck said law enforcement officers have shot a few of the birds, and it seems to scare some of them away.
“We don’t want to wipe them all out, that’s not the intent,” Streck said.
Permits limit the number of vultures that can be killed, Kellner said, because they’re so important to the ecosystem.
As is often the case, a balance must be found between nature and modern civilization. Those circling vultures might not be waiting for some poor cowboy to die of thirst in the desert, but their natural behavior could instead doom them if they begin to mosey into town.