There’s a reason—or two—vultures like hanging out near your home.
It’s no secret that humans often create problems for wildlife with their relentless clearing, building and other forms of “progress.” Not so for at least one species, which has been increasing in numbers in the Blue Ridge region and elsewhere since the late 1960s.
Researchers, of course, wanted to know why.
A study begun about 20 years ago was actually funded by an unlikely source: the U.S. Air Force.
“Vultures are a problem for aircraft collisions because they’re a large, soaring bird,” says Jacob Hill, a postdoctoral research associate at the University of Georgia’s Savannah River Ecology Lab and lead author of the report. “So the Air Force was interested in the factors that contribute to high vulture densities in places where people live, in the context of understanding them to prevent future collisions.”
In an effort to find out where vultures roost after dark, Hill and his research team analyzed detailed data gathered from 18 turkey and black vultures for nearly 8,000 nights on a military base in Beaufort, South Carolina. The birds were outfitted with transmitters that tracked their movements.
The decision to compare the two types of vultures was anything but random. Despite their scavenging similarities, turkey vultures can locate carcasses by smell, while their black-headed cousins can’t. To compensate, black vultures fly higher, following their rivals, kicking them off a carcass and consuming it.
Ultimately, the UGA researchers surmised that although vultures tend to steer clear of highly developed areas, they “tended to have more roosting in places where there was sort of a moderate amount of human influence—roads or a bunch of different types of habitat in a small area,” says Hill. In some cases, the birds even fared better in human-modified landscapes.
“They are extremely adaptable to human environments because they can roost on buildings and cellphone towers,” Hill says. “And they also will scavenge road kill and eat a lot of trash. In another study, we found about half of the vultures had some kind of plastic or trash in their diet. So human areas tend to provide most of the resources that they need, which is a place to roost and a high abundance of food.”
There’s another reason, too, why vultures like to hang out near humans. The combination of developed and open areas produces air currents that create an updraft that helps them fly. Larger than many birds, they rely on the thermals for lift.
The birds’ comfort level with humans can, however, cause conflict. “People don’t like them roosting on their property because they can be a little bit gross,” Hill says. “So having your garbage securely tied up and put away so they can’t access it might deter them from roosting on property and causing damage.”
Although they’re neither cuddly nor cute, vultures perform a valuable service to humans by removing decaying animal matter, which reduces the prevalence and spread of disease. Hill gives the example of a vulture decline that led to an unwanted domino effect in Asia. When the birds ate dead cows that had been given antibiotics, their kidneys shut down. Without natural scavengers to get rid of animal carcasses, feral dogs took over, leading to a higher incidence of rabies in people. Compounding the problem: Once vultures start to die off, it takes a while for them to rebound because they’re slow to grow and reproduce.
“They do have a really important role in the environment,” Hill says. “So it is very important that we make sure that they stay around.”
The story above first appeared in our January / February 2023 issue. For more like it subscribe today or log in with your active BRC+ Membership. Thank you for your support!