Vulture Season

Forrest M. Mims III

Some vultures spent the winter down here in South Texas, but most headed south. Now they're back doing what they do best. Two wild hogs someone shot and dumped by a roadside were quickly devoured by a dozen of them.

Vultures are often called buzzards. But that's a European name for what we usually call hawks.

Two kinds of vultures do business in Texas and much of the US. The largest is the turkey vulture (Cathartes aura) , which can have a wing span of two meters (six feet). The smaller black vulture (Coragyps atratus) has a wing span of one and one-half meters (four and one-half feet). Both species are very efficient scavengers.

If you see vultures snacking along the roadside, the ones with bald, red heads are turkey vultures. The ones with a bare face are black vultures.

If you see these big birds in flight, the ones with white wing tips are black vultures. If they're too far away to see the white wing tips, you can tell them apart by the angle of their wings. The wings of turkey vultures are tilted upward, while those of black vultures are held flat.

Figure 1. Turkey vultures spread their wings to dry after rain, but this one may have been allowing the sun's ultraviolet to sanitize its feathers. Photograph by Forrest M. Mims III.

The crested caracara (Caracara cheriway), or Mexican eagle, is sometimes confused with vultures, with which it often associates at meal time. The caracara is a tropical bird closely related to falcons. They have white wing tips like the black vulture and can be told apart by their distinctive white neck.

A group of vultures orbiting over a perspective meal is known as a kettle. From a distance, the profile of the circling birds resembles a kettle, but I think the name has a double meaning.

When vultures are drenched by rain, they find a place to perch and spread their wings to dry. But sometimes they spread their wings when there has been no rain.

Last year two vultures perched high atop a dead hackberry down by the creek on our place. There had been no rain, but the upper one shaded the lower one with its outstretched wings. Perhaps it was allowing the sun's ultraviolet rays to disinfect its wings.

It's fairly easy to take photos of vultures when they're dining along a road, but I've long wanted to get a picture of one arriving for a feast from the perspective of the main course. So recently I went down to a field by the creek and lay on the ground with a camera.

The first vulture to drift by kept on going, but the second one dropped down for a closer look. Evidently it wasn't impressed, for it circled back up and headed east. The third one turned toward the house, so I did, too.

I'll try this again and, if successful, include the best photo in a future column. My wife Minnie said I can't do this anymore, so I'll have to hide this column from her.

Forrest M. Mims III and his science are featured online at www.forrestmims.org and www.sunandsky.org. "World of Science" columns are selected and sometimes revised from columns published in the San Antonio Express-News or the Seguin Gazette-Enterprise. The columns are intended for a general audience.