On Saturday, Sept. 3, the world observes International Vulture Awareness Day.
Because they are the antithesis of cute and cuddly, vultures may seem an odd choice for their very own day. The reason is purely ecological. Though the two North American species of vultures (turkey and black) are common and widespread, the same cannot be said of species in other parts of the world.
Among the species of concern are members of the genus Gyps. The white-rumped vulture (Gyps bengalensis), for example, ranges from Pakistan and India eastward into much of southeast Asia. As recently as 1985, it was considered to be the most abundant raptor in the world.
But thanks to a dwindling supply of carrion — fewer large wild ungulates and improved animal husbandry — the vulture population began to decline. In the mid 1990s, its population suffered a sudden and significant decline. The white-rumped vulture’s population crash was exacerbated by the use the veterinary anti-inflammatory drug, diclofenac.
Vultures that ate livestock treated with the drug died of renal failure. From 2000 to 2007, Indian white-rumped vultures suffered annual population losses of almost 44 percent. Do the math; no population can sustain such losses for long.
Today, captive breeding programs show promise. But concern for Gyps vultures is not just another endangered species story. The loss of white-rumped vultures in India led to an explosion in the feral dog population, which was now free to feed on the growing number of dead animals.
As feral dog numbers increased, so did the risk of rabies. Vultures’ digestive systems destroy many pathogens. As the vultures disappeared, these pathogens were free to infect dog, rats, and people. Furthermore, feral dogs are a food source for leopards, and increasing leopard populations invade urban centers in search of dogs to eat.
Nature’s cleanup crew
These leopards then sometimes prey on human children. These are just a few reasons why we care about vulture populations all around the world. They are an important part of nature’s clean-up crew, and they make the world a safer place for people.
Fortunately, turkey and black vulture populations are healthy in North America. Turkey vultures are widespread and easily recognized by their bright red, naked head and, in flight, by wings held in a shallow “V.”
Black vultures on the other hand are a more southern bird. Their naked heads are black, they hold their wings flatter in flight, and they show white “windows” on their wings. Many people mistakenly call vultures “buzzards.”
This misnomer dates back to the 1600s when Europeans began colonizing the New World. In Europe, large hawks were (and still are) called buzzards. When colonists saw vultures soaring overhead, they naturally called them buzzards. If you’ve ever seen a vulture up close, you know it’s a creature only a mother could love.
But many of their habits are even more revolting than their appearance. Their table manners come immediately to mind. Vultures eat dead, rotten, and even putrid flesh. The more aromatic, the better. Field experiments have shown that turkey vultures use odors to find food. And compared to other raptors, a vulture’s bill and talons are relatively weak.
Decayed meat is tender and easier to tear apart than fresh meat. Vultures’ taste for carrion also explains why they have featherless heads. Because they spend so much time poking their heads into dead body cavities, their head feathers would be forever soiled.
The naked head promotes cleanliness and hygiene. But vultures don’t restrict their vile habits to eating. During hot summer weather, they practice evaporative cooling by urinating on their legs. And if cornered at a nest, they discourage predators (and overzealous ornithologists) by projectile vomiting a foul, soupy fluid in the direction of the intruder.
Fortunately, most of us never witness these offensive behaviors because we usually see vultures soaring overhead, often at great heights. Vultures have elevated gliding to an art form. Usually they’re content to ride the atmosphere’s thermal currents.
It’s easy to dismiss vultures as disgusting creatures. But to vultures, their habits are normal, natural and adaptive. And as inhabitants of other parts of the world have learned the hard way, vultures are an essential part of healthy ecosystems.
Send questions and comments to Dr. Scott Shalaway, RD 5, Cameron, WV 26033 or by email via my web site, http://scottshalaway.googlepages.com