A study from the Norwegian Institute for Nature Research (NINA) found that painting one out of four white wind turbine blades black reduces the number of birds killed by the blades by 72%.

Wind turbine tweak

Why does this work? The scientists say it’s because of something called “motion smear.” The movement of the all-white blades makes them appear invisible to birds, who have excellent peripheral eyesight, but they can’t see as well when they look forward. So having one black blade is easier for the birds to spot.

The study, which is published in Ecology and Evolution, was conducted on Norway’s island of Smøla for 7.5 years before the blades were painted and 3.5 years after treatment.  

Of the eight wind turbines used in the research, four were painted and four were left bare. There were a total of 1,275 searches by sniffer dogs conducted for dead birds between 2006 and 2016. The birds that benefited the most from the painted blade were large birds and birds of prey, such as eagles and vultures.

Wind turbines killed six white-tailed eagles before they were painted, but no deaths were recorded after the black blade was added.   

Further, painting the towers black helped, too. “We painted the lower part of 10 turbine towers black. This reduced the mortality for willow ptarmigan by almost 50% compared to unpainted wind turbines in the same area,” says NINA researcher Bård Stokke.

Electrek’s Take

We at Electrek have written about birds and wind turbines before. Of course every bird that can be saved is a huge win, so this is a simple yet innovative solution that should just become standard practice and make green energy even better. But wind turbines are not a leading cause of bird deaths. Here’s what is:

Agriculture, deforestation, and urbanization. Simply put, it’s habitat destruction. And let’s include pesticides here, under the category of agriculture. According to Sibley Guides, “Pesticides may kill 72 million birds per year or possibly many more. The sublethal effects of pesticides may also make the birds more susceptible to predators or unable to reproduce, essentially killing them.”

Fossil fuels and climate change. Oil fields could kill up to 1 million birds a year, according to the Bureau of Land Management via factcheck.org. Oh, and climate change, of course, which threatens two out of three bird species in the US. As the Guardian explains, “Climate change compounds those problems by altering bird habitats.”

Sibley Guides estimates oil fatalities at an even higher rate. The bird reference guide says:

Oil spills kill hundreds of thousands of birds a year or more. Some of this occurs in dramatic large spills, but most probably occurs in thousands of small incidental spills that are never reported or documented.

Oil and wastewater pits may kill up to 2 million birds per year.

Cats and windows. In 2014, Treehugger [via USA Today] listed the greatest threats to birds by fatality numbers. According to the 2014 State of the Birds Report (the most recent report with these statistics), wind turbines came in eighth. The top threat to birds is cats (2.4 billion), followed by windows (599 million), cars (200 million), power lines — collision (25 million), communication towers (6.6 million), power lines — electrocution (5.6 million), agricultural chemicals (US number unknown, Canada is 2.7 million), and wind turbines (234,000).

A couple of blue jays keep flying into my living room window — and they get my (indoor-only) cat all riled up. So the above doesn’t surprise me at all.

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