Black vultures are the most populous vulture in the Western Hemisphere, but they’re relatively new to New York State. Here are some things to keep in mind next time you see a dark shape circling above.
Scientists aren’t sure why they’re moving north.
Up until the mid-20th century, the black vulture ranged from South America to Virginia. Since then, it’s continued to move north, nesting in New Jersey in the 1980s and New York in the 1990s. Some believe global warming could be a factor, but Kevin McGowan, an ornithologist at the Cornell Lab of Ornithology, says that’s not always the case when an animal moves north. He pointed out that recent surveys show just as many bird species moving south as north.
Other possible factors include increased food availability, especially more deer roadkill, phasing out of DDT, and changing attitudes about vultures. “It used to be legal and socially acceptable to shoot vultures,” said McGowan.
The first breeding nest was discovered on the Mohonk Preserve, and that’s still one of the best places to spot one.
Former research associate at the Mohonk Preserve Joe Bridges discovered a nest on the eastern side of Bonticou Crag in 1997 while climbing. “I saw a black vulture sitting on a rock at ground level and I thought it was curious,” he remembers. “And shortly after that I looked at a hole between two rocks and saw another black vulture, and that one moved back in a few minutes and I saw two eggs on the ground.” He didn’t realize it at the time, but he’d just observed the first breeding pair of black vultures in New York State.
Today, hikers at Bonticou Crag and at other parts of the preserve often get a close look at both black and turkey vultures, sitting on rocks and in trees surveying the valley below, and gliding at eye level, taking advantage of the thermals created by the Shawangunk Ridge’s steep rise.
They let turkey vultures lead them to food, then team up to chase them away.
Turkey vultures can smell carrion from over a mile away. Black vultures, who have a limited sense of smell, fly above turkey vultures and wait for them to discover food and follow them to the carcass. Turkey vultures are larger than black vultures, but they’re no match for a group working together.
Although the turkey vulture is on the losing end of these interactions, so far there’s no sign it’s affecting their population numbers which, like the black vultures, continue to increase. It seems there’s enough roadkill to go around.
They’re not closely related to Old World vultures.
They share the name, bald head, circling flight and highly acidic digestive system, but New World vultures like the black vulture, turkey vulture and California Condor aren’t closely related to Old World species like the griffon and Egyptian vultures. Their common vulture characteristics are a result of traits selected for a similar lifestyle. New World vultures are actually more closely related to storks, with which they share a foul, though effective, means of thermoregulation. (See next entry.)
To cool off, they defecate on their legs.
Humans sweat. Dogs pant. New World vultures… have another means of generating moisture to affect evaporative cooling. It’s called urohidrosis, from the Greek for “urine” (uro) and “hidrosis” (sweating).
They sometimes prey on live animals.
Some Native American tribes called the turkey vulture “peace eagle” because it survives without killing. That’s not true of the black vulture, which is known to sometimes prey on weak and newborn live animals. The frequency of this behavior is disputed. Ranchers in some states estimated tens of thousands of dollars in annual losses, while scientists question how many of these cases are due to coyotes or death by other means. “It’s possible but man, they’re just not made to be predators,” said McGowan, the Cornell ornithologist. Vultures lack talons and their bills are made to pick, not kill. “They’re not really capable of delivering a convincing killing blow.”
They can be destructive.
When black vultures roost in a populated area they can cause problems. They’ve been known to pick at and destroy rubber roofing materials, shingles, screen doors, windshield wipers and sunroof gaskets. Scientists aren’t sure why they do this. They don’t collect the material or use it to build nests. They just tear it. One explanation could be that they’re just inherently curious about certain man-made materials, and the destruction is a form of play.
They’re very social.
Curiosity and sociability often come together. So it is with the black vulture. In addition to working together when feeding, they spend much of their time together, often roosting in large numbers. Related birds stick together and preen one another, while most fights seem to be between non-kin.
How to tell the difference between black and turkey vultures.
Turkey vultures: Slightly larger, red head, legs held tight to body, wings form shallow-V in flight, less flapping, silvery wings when viewed from beneath.
Black vulture: Smaller, black head, legs often hanging down, wings held straight in flight, more flapping, wings black except white patch on tips when viewed from beneath.