Bird deaths down 70 percent after painting wind turbine blades (arstechnica.com)

The study ran for nine years at Norway’s Smøla wind farm.

Experts say “When a bird comes close to the rotating blades, the three individual blades can ‘merge’ into a smear and birds may no longer perceive it an object to avoid. One black blade interrupts the pattern, making the blending of the blades into a single image less likely.”

You can read more about the research here  https://group.vattenfall.com/press-and-media/newsroom/2022/black-turbine-blades-reduce-bird-collisions