Monday, June 4, 2012

Unpopular birds do important work

A wake of vultures make fast work of an unfortunate raccoon

Vultures have many names. When flying, they are a kettle. When perched, a venue, a committee or a volt. But the label I find most fitting is when a group of these large, black-feathered, bald-headed scavengers are standing around the carcass of a recently killed animal. Then they become a wake.

I chanced upon a wake of vultures as I was heading out the driveway. Although on my way to town, I put my mission on hold to investigate theirs. What I observed piqued my curiosity about these seldom-appreciated birds.

Two species of vultures live in Florida — the turkey vulture and the black vulture. Both are carrion eaters that make fast work of recently killed or decaying carcasses. The four birds I saw were all black vultures (Coragyps atratus). Each of the 2-foot tall, 4- to 6-pound creatures was fixated on the dead body of a mature raccoon. So intent were the birds on their impending feast they barely budged when I pulled up alongside and parked the car.

Vultures have bodies well suited to their role as the animal kingdom's cleanup crew. Their sharp, slightly hooked bills can tear through tough skin and fur while their featherless heads make venturing after internal organs a less sticky, messy affair. The bald heads of turkey vultures are red while the bumpy-skinned tops of black vultures are black or gray.

In addition to having different head colors, black vultures are smaller than turkey vultures and only the tips of their wings are white while the entire underside edge of turkey vulture wings is a grayish-white color. Black vultures also have white legs, a feature turkey vultures lack.

The two species have other differences as well. Turkey vultures tend to be solitary animals that use their strong sense of smell — a rare characteristic in birds — to pick up the odor of ethyl mercaptan, a gas released just after an animal dies. Once a turkey vulture picks up the scent of decay, it settles in for a prolonged feast.

Unless it is chased away by a kettle of black vultures.

Black vultures don't share their cousin's strong sense of smell or their desire for solitude. They are pack animals, traveling, feeding and roosting in groups. The food they eat is also different from what turkey vultures consume.

While turkey vultures only eat carrion, black vultures will occasionally attack vulnerable live animals like newborn calves. They are also not above frequenting landfills, gleaning road kill and stealing food away from their turkey vulture relatives.

I don't know how the raccoon in my yard died or what killed it but as I watched, its lost life provided others with a substantial meal. Rather than rush in, the black vultures stood patiently around the ill-fated mammal until one bird stepped forward to make the first move. After that, much ripping and tearing ensued as the scavengers competed with one another for prime pieces of meat.

It took about three days for the vultures (with help from ants, flies, beetles and a neighbor's stray dog) to convert the raccoon's fur-covered flesh into a scattering of bones and teeth. By then, the vultures were gone, probably neck-deep in other decaying matter.

Despite their diligent efforts to keep the planet free of decaying bodies, we humans don't think much of vultures. If we give them any thought at all, it is a dismissive disparaging one. They're ugly. They're vulgar. They are harbingers of doom. But distasteful as it may be to watch one animal plunge headfirst into another critter's carcass, these solemn stalkers of the dead and dying play a vital role in the circle of life.

No matter what they are called — a kettle, committee, venue, volt or a wake — vultures do the dirty work of keeping the world clean and for that, we should be grateful.

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