Wind energy is one of the cleaner ways to generate electricity. But as wind farms expand, they can create another environmental challenge: bird collisions with rotating turbine blades.

Raptors, including white-tailed eagles, can be particularly vulnerable. At Norway’s Smøla wind farm, for example, researchers have recorded several white-tailed eagle deaths each year. So, could a small change to a turbine make a big difference? Researchers decided to test an unusually simple idea: paint one of the three rotor blades black.

Why Paint Just One Blade?

The answer lies in how birds see moving objects. When all three turbine blades rotate, their rapid movement can create what researchers describe as “motion smear.” In simple terms, the blades can become difficult to distinguish as separate objects.

Painting one blade black may make the rotating structure more visible against the background. The idea was inspired by earlier laboratory experiments in the United States that explored whether making moving objects more visually distinct could help birds detect them.

Researchers at the Norwegian Institute for Nature Research tested the approach at the Smøla wind farm, located off Norway’s western coast. The results were striking. According to the study, turbines with one painted blade recorded more than 70% fewer bird fatalities compared with neighbouring turbines whose blades remained unpainted.

Does One Black Blade Really Make a Difference?

It could—but researchers say the story is not quite that simple. The study suggests that making turbine blades easier for birds to see may help them avoid collisions. However, the researchers caution that the effectiveness could vary depending on the location and the bird species involved.

More studies are therefore needed at other wind farms before the approach can be considered broadly effective. Research is already being considered at sites in countries including the Netherlands and South Africa.

Can Wind Energy and Wildlife Coexist?

The finding opens an interesting possibility: perhaps some wildlife protection measures do not require major changes to wind turbines. A simple paint job could potentially become an additional tool where bird collisions are a known problem. However, conservation groups stress that the first priority should still be choosing wind farm locations carefully, away from areas where they could pose significant risks to wildlife. 

The bigger question, then, is not whether wind energy or wildlife should win. It is how we can design cleaner energy systems that leave more room for nature too.