Gyrating Vultures

While wandering through the woods recently my attention was drawn to five turkey vultures lazily circling. It was like a slow, graceful aerial dance; almost mesmerizing in their elegant undulations. The turkey vulture is a large, unsightly bird, over two feet (65 cm) long, with a wingspan of over five feet (1.7 m). This bird provides a valuable service to the environment by consuming carrion... a major benefit to the world. Without vultures, dead critters would lay around putrefying and spreading disease.

The five birds I saw gracefully circled one another—forming a spiral of wings that slowly revolved. The birds' relative positions were maintained, which caused a sensation for me of seeing their formation as if it was a fixed entity, rather than five individual beings. Yet one bird—near the top of the group—drew my attention, as it moved more independently. It seemed as if it was like a musical conductor of a small, silent vulture orchestra. It was a beautiful sight.

In a few moments I noticed that the vertical axis of the rotating vulture helix was very leisurely drifting westward—reminiscent of a tornado or a water spout, in extreme slow motion. Then I noticed that, for the time that I was watching the show, I had seen no wing flaps. For a couple of minutes or more these birds were soaring—tipping a bit from side to side as vultures do, but with their wings frozen in position, outstretched and in a slight upward angle.

The vultures were being buoyed up by rising warm air at the end of the day, as heat waves from the warm ground rose into the cool evening air. These rising thermals are advantageously used by large birds such as vultures, eagles, and hawks, to soar with minimal energy expenditure. It takes a large effort for these birds to lift themselves from the ground, so they use thermals, much like humans do with hot-air balloons. My vultures were free-riding on a small thermal, that was not strongly rising, so they stayed at about the same 30 foot (10 m) elevation—floating and circling unhurriedly westward.

When people see vultures circling, they expect that the birds are searching for carrion. These birds will float in lazy circles, their exquisite sense of smell (for a bird) seeking those rising odors of decaying flesh. Were these vultures looking for dinner? Was it a family out for an evening flight? Were they simply enjoying themselves, as they received a free ride on the evening warm air? If I could lose my fear of heights and have my arms transform into giant wings—sort of like a hang glider—I'd have wanted to join the vulture ballet that evening. But I was content to remain a grounded human, as I soared with the birds in my imagination.