If you see vultures circling overhead, it doesn’t mean you’re about to die—in fact, you could just be near a power plant.
The large, bald-headed birds float on rising currents of warm air known as thermals, which they use to soar high into the sky without beating their wings, thereby saving energy.
Now, scientists have shown that vultures also use air currents from power plants to get a lift. Thermal power plants, which produce power through steam, generate stronger and hotter thermals than those that occur naturally, making for an extra speedy vulture elevator.
Researchers surveyed six power plants in the central Amazon in Brazil and found black vultures or turkey vultures soaring above the plants in nearly 80% of the surveys, they report in the current issue of The Wilson Journal of Ornithology. The researchers counted the largest numbers of vultures in late afternoon, but location mattered: Power plants near areas where the vultures tended to roost had more visitors in the early morning and late afternoon, whereas power plants near feeding sites had more at midday.
Birds congregating at power plants could be bad news for airplanes—vulture strikes are a significant problem in Brazil. The authors suggest that new thermal power plants should be built more than 20 kilometers from airports, and air traffic controllers should alter flight paths to avoid existing ones.