How Dangerous Are Wind Turbines to Bird Populations?

What’s the story?

• Wind turbines are an effective way to produce sustainable energy, but a usual counterargument to wind farms is their impact on birds. While this infrastructure can be responsible for a slight decrease in bird populations, many wonder whether this outweighs the need for this form of green energy. 

How lethal are wind turbines? 

• In the U.S., three major studies found that wind turbines kill around 100,000 to 450,000 birds a year. Compared to other causes of bird deaths, these figures are relatively low. Yearly, about 1 billion birds are killed by colliding with buildings, while cats in the U.S. kill up to 4 billion birds. According to this research, wind farms kill .01% to .04% of birds killed by buildings and cats. 
• While these figures aren’t too notable, conservation groups still raise concern over the expansion of wind farms throughout the world. Animal activists especially fear an exponential increase in wind turbines as we try to move away from fossil fuels and towards renewable energy sources. 
• The U.S. Fish and Wildlife Service estimates that turbine-related bird deaths will grow as there are more and more wind farms annually. It’s predicted that globally, bird deaths from wind farms will increase to over 2 million per year by 2050. 
• However, this estimate is pale in comparison to the birds that will die if the climate crisis isn't addressed through solutions like renewable energy. 

How do wind turbines kill birds?

• Birds can be killed by the spinning blades of wind turbines and the collision with high-voltage electric power lines that travel to and from wind farms. Birds are unlikely to see a turning wind turbine blade as an object they need to avoid. While a bird’s eye is typically stronger than a human’s, its vision is flat and lacks depth perception. 
• Wind turbines threaten predatory birds in particular, such as Peregrine and Prairie Falcons, Golden and Bald eagles, Red-tailed and Swainson’s hawks, and kestrels. These birds spend much of their day soaring and scanning the ground for prey, making them more likely to fly into a wind turbine blade unknowingly. 

How to protect birds from wind turbines

• The best way to limit bird deaths from wind turbines is to build wind farms away from conservation areas and migration paths. The U.S. Fish and Wildlife Service developed a guide for wind turbine installers to help avoid these regions and protect bird populations. 
• Energy companies will also work with conservationists and ecologists to avoid these population impacts. Some wind farms have AI sensors that can shut off the turbines for incoming birds. 
• Turbine manufacturers have begun installing sonic deterrents to ward away birds by sending out ultrasonic frequencies. 
• A more straightforward solution is painting turbines with UV paint, or even purple, which birds can spot and know to avoid. 

Are you concerned about wind turbines killing birds?

-Jamie Epstein

(Photo credit: iStock/Ian Dyball)