Phys.org, Brian Wallheimer
Wind turbines are known to kill large birds, such as golden eagles, that live nearby. Now there is evidence that birds from up to hundreds of miles away make up a significant portion of the raptors that are killed at these wind energy fields.
Using DNA from tissue and stable isotopes from the feathers of golden eagle carcasses, researchers from Purdue University and the U.S. Geological Survey found that golden eagles killed at the Altamont Pass Wind Resource Area in northern California can come from hundreds of miles away. Golden eagles are a species of conservation concern, so understanding population-level differences and how individuals interact with turbines is key to meeting a U.S. Fish and Wildlife Service target of no net loss to their populations.
The APWRA is one of the oldest wind farms in the country and one of the largest in the world originally with around 5,000 turbines. Worldwide, such facilities have been responsible for the deaths of 140,000 to 328,000 birds and 500,000 to 1.6 million bats, raising questions about their effects on population sustainability.
“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,” said J. Andrew DeWoody, a Purdue professor of genetics in the Department of Forestry and Natural Resources. “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.”
Collaborator David Nelson, a stable isotope ecologist with the University of Maryland Center for Environmental Science, tested the birds’ feathers for stable hydrogen isotopes, which can be used to determine where the birds likely grew their feathers. The research team determined that about 75 percent of the 62 birds were from the local population. The remaining 25 percent likely migrated into the area before they were killed. Read article