thousands of birds and bats are killed annually by wind turbines. Causes of death include collision and barotrauma—internal injuries caused by exposure to rapid pressure changes near the trailing edges of moving blades.
The U.S. Fish and Wildlife Service estimates that between 140,000 and 500,000 bird deaths occur at wind farms each year.
The most significant threat is posed to species of large, threatened and high-conservation-value birds such as golden and bald eagles, burrowing owls, red-tailed and Swainson’s hawks, peregrine and prairie falcons, American kestrels and white-tailed kites.
Since large birds have much lower reproductive rates than small birds (golden eagles, for example, have just one or two chicks in a brood less than once a year), their deaths have a far greater impact on the overall population of the species.
Wind turbines have also been found to be one of the leading causes of mass bat mortality—with some studies pinning fatalities at 888,000 bats a year.
“Unprecedented numbers of migratory bats are found dead beneath industrial-scale wind turbines during late summer and autumn in both North America and Europe,” says Paul Cryan, a research biologist with the U.S. Geological Survey. “There are no other well-documented threats to populations of migratory tree bats that cause mortality of similar magnitude to that observed at wind turbines.”
Bats may not be many people’s favorite creatures, but they play an important role in the planet’s ecosystems. Not only do the aerial mammals consume hordes of pest insects—they’re also instrumental in pollinating flowers and dispersing seeds to regenerate rainforests. Bats can potentially be cute too. (Images courtesy of American Wind and Wildlife Institute.)
Bats can potentially be cute too. (Images courtesy of American Wind and Wildlife Institute.)
