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Scary Scavengers

Despite unpleasant habits such as defensive vomiting, vultures play a key role as nature's garbage collectors.

By Sheryl Smith-Rodgers

Michele Dudas only meant to help when she spotted what looked to be a bird foot sticking out the back end of a dead cow. "I was clueless about vultures," she says. "Now I know better!"

Remembering that fall morning more than 20 years ago still makes Dudas laugh. At the time, though, it wasn't funny at all.

"I was living in a rent house on a ranch northwest of Lake Bridgeport," she recalls. "Near the barn, I saw a pregnant cow so big she was ready to burst. It stormed that night, and I made up my mind to check on her the next morning."

Sadly, the cow didn't survive the night, and neither did her calf, which was apparently eaten by coyotes. As Dudas surveyed the carnage, she noticed the cow's abdomen move, and then she saw a bird's foot. Thinking it was stuck inside the carcass, Dudas began to tug on the bird, which turned out to be a black vulture.

"He was quite messy," Dudas says. "I got him out, and he ran a few feet away from me. Then he turned around, raised his wings, and spewed this awful, purple, nasty, smelly goo all over me! I thought, 'Why, you ungrateful thing!' I had to walk home with the stuff all over me. I was a mess."

Dudas, who works as a naturalist at the Heard Natural Science Museum and Wildlife Sanctuary in McKinney, has since learned more about black vultures, namely that they can vomit with a vengeance when threatened.

Vile. Hideous. Disgusting. Ugly. Spooky. Such are the adjectives commonly used to describe the low bird on the animal totem pole. Much like spiders and snakes, vultures have few admirers. What's to love about a scrawny-headed creature that relishes road kill on a regular basis? Confirming that age-old view, the Old Testament classifies vultures as an "abomination." Edgar Allan Poe gave his murder victim the "eye of a vulture" that ultimately drove the killer insane. Walt Disney portrayed vultures in his animated productions as goofy and witless.

They may look goofy to most, but to others, vultures have been an important source of inspiration and guidance. Orville and Wilbur Wright designed their first powered aircraft based on a turkey vulture's curved wingtips. Folklorist J. Frank Dobie, who often watched them glide and soar, wrote that "nothing in the sky is more serenely graceful."

Until recently, ornithologists classified vultures as raptors, along with eagles, hawks and falcons. Studies of DNA, however, concluded that New World vultures are more closely related to storks, gulls, pelicans and loons; thus, the birds were reassigned to the order Ciconiiformes. Though commonly referred to as buzzards, technically, vultures are not buzzards. The misnomer comes from the French word busard, which means hawk. In the Old World, busard refers to the genus of soaring hawks called Buteo.

Two vulture species, both predominantly black in color, occur in Texas - the turkey vulture (Cathartes aura) and the black vulture (Coragyps atratus). Like their namesake, turkey vultures have a bright red, bald head. Their wing spans can reach up to 6 feet. When flying, turkey vultures hold their wings in a shallow V formation called a dihedral, tilting and rocking as they soar.

Black vultures aren't as graceful in the air. Slightly heavier with both a shorter tail and wingspan (5 feet), they alternate between quick wing flaps and short glides. Black vultures have a white patch on their wings' undersides and featherless gray heads.

Males and females of both species are indistinguishable. Pairs usually mate for life. Females typically deposit two eggs on the ground in a clearing, on cliffs and in tree cavities; no nests are constructed. Both parents incubate the eggs for approximately 40 days. They also jointly feed the nestlings regurgitated stomach contents; weak talons preclude them from carrying food.

Vultures lack a syrinx (voice box) so they're generally silent, but they will occasionally hiss or grunt.

As Mother Nature's garbage collectors, vultures have several built-in mechanisms for staying healthy. Their bald heads shield them against bacteria that would otherwise cling to head feathers when scavenging inside carcasses. Infected meat deadly enough to kill a coyote doesn't phase a hungry vulture; its digestive tract somehow destroys virulent pathogens, which curtails the spread of diseases in nature.

Even a vulture's impolite method of defecating protects him. The bird urinates a white mixture of uric acid and feces directly on its legs and feet, which cools the bird as the urine evaporates. The highly acidic mixture also kills any bacteria and parasites clinging to the vulture's feet from a previous meal.

Surprisingly, vultures are very clean birds. They enjoy bathing in water and will spend two to three hours preening their feathers every day.

Though similar in appearance, the two species differ in temperament. Black vultures, the more aggressive of the two, occasionally kill small birds, mammals and young livestock. At carcasses, they shove turkey vultures aside. If threatened or trapped, black vultures will struggle violently and vomit vile goo at their attacker, whereas turkey vultures have been known to roll over and play dead. Even so, they vomit, too.

Vultures - sometimes numbering in the hundreds - congregate in the evening at communal roosts in trees and on power line structures. The two species often roost side by side. In the morning, turkey vultures take off to eat first, then search for carrion. Their keen sense of smell and sight enable them to locate food miles away. Returning to the communal roost toward day's end, they somehow communicate to other vultures about their finds, and the next morning everyone reports to the scene to dine. Black vultures often tag along after the turkey vultures and barge in at the lunch table.

In February 2003, turkey vultures inadvertently assisted in the recovery of astronauts' remains in Texas following the Columbia disaster. Bill Kohlmoos, former president of the Turkey Vulture Society, advised FBI officials regarding the vultures' reconnaissance habits. They learned to watch for birds flying in a circle. If they began spiraling downward in a tighter circle, that meant the vultures had spotted something. Federal authorities plotted locations by GPS and then sent recovery teams to designated sites. "They did have success using the turkey vultures," says Kohlmoos, who later received a letter of commendation from the FBI.

What vultures lack in looks, they make up for with brains and an affectionate, fun-loving nature. Ramona VanRiper, Turkey Vulture Society president, can vouch for vultures being sweet and personable because she's known several, including one named Clem. "Vultures raised by humans learn quickly to love and trust us," she says, "and will often respond to human attention long after they have successfully reassimilated into their natural communities."

Vultures enjoy games, both in the air and on the ground. Several years ago, Brush Freeman of Utley observed two juvenile black vultures playing with a stone in eastern Travis County. "One would pick up the rock and drop it, the other would do the same, back and forth," he recalls. "This went on for several minutes, like clockwork every 15 seconds. It was a very strange thing to see in birds."

Playful. Smart. Graceful. Clean. Such are just a few of the adjectives that vultures everywhere certainly deserve. It's about time they got some good press.

For more information and vulture anecdotes, visit the Turkey Vulture Society's Web site at vulturesociety.homestead.com

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