Study: Cats, Cell Towers are More Deadly to Birds Than Wind Turbines

Wind energy has famously pitted environmentalists against each other – renewable energy and climate action advocates vs. wildlife conservationists concerned about wind turbines injuring or killing birds. But a new study, funded by the American Wind Wildlife Institute (AWWI), reveals that bird fatalities resulting from collisions with wind turbines are extremely low; in fact, cell towers and cats kill a far greater number of birds than wind turbines do, the peer-reviewed report found.

Wind turbines are responsible for an estimated 214,000 to 368,000 bird deaths each year, according to A Comprehensive Analysis of Small-passerine Fatalities from Collision with Wind Turbines at Wind Energy Facilities. This is a small fraction of bird fatalities compared with the 6.8 million annual deaths caused by collisions with cell and radio towers and the 1.4 to 3.7 billion fatalities from cats, say the report’s authors, environmental consulting firm West, Douglas Johnson from the U.S. Geological Survey and Joelle Gehring of the Federal Communications Commission.

The report, which focuses on passerines (small birds such as songbirds), is the most comprehensive study of the impacts of wind turbines on small bird populations, said Taber Allison, AWWI director of research and evaluation, in a statement.

“While total fatality numbers inform the scale of the issue, one of the most important scientific contributions from this research is our new understanding  of the level of impact on individual songbird and other small passerine species,” said the study’s lead author, Wallace Erickson of West, in a statement. “Using conservative assumptions, we estimate that on an annual basis, less than 0.1 percent (and typically less than 0.01 percent) of songbird and other small passerine species populations in North America perish from collisions with turbines.”

Erickson and his co-authors analyzed data from 116 studies conducted at more than 70 wind energy facilities in the United States and Canada, adjusting for the fact that not all birds killed by wind turbines can be detected during surveys: Some bird carcasses may be scavenged or will decompose before they are counted, while others may be missed by surveyors.

The study’s conclusion? That wildlife advocates should continue to push for bird-friendly locations for wind turbines, but they should also focus on the numerous other “threats that are far more serious in terms of their effect on the populations of these birds,” Taber said.

Climate change is one such threat. The AWWI pointed out that the National Audubon Society has just completed a report for the U.S. Fish and Wildlife Service, finding that climate change puts more than half of all bird species in North America at risk. Of the 588 bird species Audubon studied, 314 species are projected to lose more than 50 percent of their current climatic range by 2080.

Audubon spokesman David Ringer told USA Today that the nonprofit is still reviewing the AWWI’s study, but the organization strongly supports “properly sited wind power as a renewable energy source that helps reduce the threat posed to birds and people by climate change."

The AWWI’s report can be critiqued for concentrating on small birds and not including larger, endangered birds such as bald or golden eagles in the study (passerines accounted for 63 percent of the nearly 5,000 bird deaths observed at wind farms, while raptors made up 8 percent). But the AWWI said it plans to sponsor comprehensive studies of other bird species – including eagles and prairie birds – in the near future. Passerines are actually the largest order of birds and include half the world’s bird species – therefore, they deserve to be studied, too, and were a good place for scientists to start to analyze the effects of wind turbines on bird populations.

AWWI’s study is important in carrying on the conversation between proponents of clean energy and wildlife campaigners – because, at the most basic level, the two sides have the same goal: a planet that is safer and healthier for all living things.

Image credit: Flickr/Patrick Finnegan

Passionate about both writing and sustainability, Alexis Petru is freelance journalist based in the San Francisco Bay Area whose work has appeared on Earth911, Huffington Post and Patch.com. Prior to working as a writer, she coordinated environmental programs for Bay Area cities and counties. Connect with Alexis on Twitter at @alexispetru