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Painting A Wind Turbine Blade Black Reduces Bird Deaths By 70%, Study Finds

Updated September 8, 2021

The future will be powered largely by clean, fossil-fuel-less renewable energy and it's visible in how solar farms and wind turbines are increasingly popping up. Indeed, the U.S. even saw a period of 40 days in 2020 when energy output from renewable sources like solar, wind, and hydroelectric power exceeded the energy generated by coal.

However, wind power in particular has seen significant opposition, especially due to its effects on bird populations. A project that would have seen a large investment in wind turbines along Lake Erie was recently put in jeopardy by Cleveland's city council, for example, over concerns it would seriously harm migratory birds.

Perhaps it might be worth paying attention to a study out of Norway that found a simple solution to the bird problem.

One of the biggest issues with wind turbine blades is that they kill too many birds.

Unsplash | Dimitry Anikin

The U.S. Fish & Wildlife Service reported that wind turbines cause between 140,000 and 500,000 bird deaths every year. Mind you, the FWS also estimates that power lines kill between 8 and 57 million birds every year, and house cats kill up to 3.7 billion birds per year.

Nevertheless, bird deaths have made wind turbines a political target on numerous occasions, as with the Cleveland project. Even President Trump referred to wind turbines as "bird graveyard[s]."

And so researchers have been studying ways to reduce the harm wind turbines pose to birds, and they've found a surprisingly effective solution.

Ecology and Evolution

As with glass on buildings (which is responsible for up to 988 million bird deaths a year in America, according to the FWS), birds seem to have trouble detecting when certain objects are in their flight paths. The rotating blades of a wind turbine certainly qualify.

So, to make the blades easier to see, researchers painted a single blade on a wind turbine black.

Compared to other, unpainted wind turbines, painting a single blade reduced bird deaths by 70%.

NINA | Roel May

It was a fairly significant study, undertaken at the Smøla wind farm, one of the largest onshore wind farms in Norway. There, the 68 turbines stand about 70 meters (230 feet) tall, each with three 40-meter (130-foot) blades.

Between 2006 and 2013, regular checks of four wind turbines found 18 bird carcasses, dead from collisions with the turbines, including six white-tailed eages.

Those four turbines all had a single blade painted black, and over the next three years, only six birds died after colliding with the turbine blades.

Facebook | Norsk institutt for naturforskning

Nearby turbines with all-white blades were responsible for 18 bird deaths. The researchers concluded that the single black blade provided just enough contrast to make them easier for birds to see and avoid.

"The expectation is that this design reduces so-called motion smear, making the blades more visible to birds," study co-author Roel May of the Norwegian Institute for Nature Research told the BBC.

While the study is promising, wildlife experts are expressing some caution.

Facebook | Norsk institutt for naturforskning

It is, after all, just one study. Even May acknowledged that what worked in Norway might not work elsewhere.

"Although we found a significant drop in bird collision rates, its efficacy may well be site- and species-specific," May told the BBC. "At the moment there exists interest to carry out tests in the Netherlands and in South Africa."

The study was published in Ecology and Evolution.

h/t: BBC

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