Dangers of Wind Energy: Wind Turbines Deadly to Golden Eagles, Migratory Birds

There's a disadvantage in using wind turbine for energy -- it's killing birds. A team of researchers has found that this technology for wind energy is not only deadly to local birds but also those migrating from hundreds of miles away.

According to the study published in the journal Conservation Biology, a team of researchers from Purdue University has discovered that wind energy fields could kill birds not local to the area including large species like the endangered golden eagle.

In order to assess how deadly wind turbines are, the team used the DNA and isotopes from the dead golden eagle's feathers. By using the stable isotopes in the bird's feather, scientists were abe to determine where the bird originated. The researchers found out that about 75 percent of the 63 birds found dead in the area were local birds while the remaining 25 percent were migratory birds.

Read: Wind Farms Threaten Breeding Success Of White-Tailed Eagle, New Study Shows

Results also showed that the golden eagles found dead at the Altamont Pass Wind Resource Area (APWRA) located in Northen California came from hundreds of miles away, specifically in the western U.S.

"Eagles tend to use that habitat around the turbines. It's windy there, so they can save energy and soar, and their preferred prey, California ground squirrels, is abundant there," Purdue University professor J. Andrew De Woody explained via Science Daily.

"As they soar, these eagles are often looking straight down, and they fail to see the rapidly moving turbine blades. They get hit by the blades, and carcasses are found on the ground under the turbines," he added.

APWRA, one of the oldest and largest wind farms in the world, has been responsible for 140,000 to 328,000 bird deaths and 500,000 to 1.6 million bat deaths. Todd Katzner, co-author of the study, said that to evaluate the effect of a wind farm to the environment, local birds are not the only that should be taken into consideration but migratory birds too, such as golden eagles.

This new discovery is important because of the growing concern in the golden eagles' declining population in several states. Unerstanding the effect of wind turbines to the birds' fatality rates could shed more light to the population loss.