Amid concerns about climate change and global warming due to the use of fossil fuel, renewable energy sources have been given priority. Among them, the wind turbine has been a popular choice but there are concerns related to this as well as birds are killed by its blades. But a study has come up with an inexpensive solution to reduce bird mortality by over 70 percent.

The major problem with wind turbines or windmills is that birds are attracted to the blades and get killed. A study done in 2013, found approximately 328,000 birds are killed every year because of wind turbines. The number could be more in 2020 as the number of wind farms has also grown exponentially. That's one of the reasons, why many politicians including U.S. President Donald Trump are not in favor of wind energy. They call it a "bird graveyard".

Wind turbines
Wind turbines causes thousands of bird deaths every year Wikimedia Commons

The sentiment has been echoed in many European countries as well but a group of Norwegian researchers conducted a study to find a solution. They observed that motion smear left by the rotating blades creates a problem for birds and it can't detect the blades.

Black Paint

However, the study conducted at Norway's Smola islands found that a simple coat of black paint on one of the rotating blades could reduce the number of birds strikes and deaths by over 70 percent. Their research was published in journal Ecology and Evolution on Tuesday, August 26.

The wind farm in Smola, Norway is one of the largest in the country with 68 turbines spread over 18 square kilometers, making it the ideal place to conduct an extensive study. The research team was keen on finding out a measure that could reduce bird deaths. During their study, they tested various methods and settled on black paint that reduces motion smear.

painted wind turbine
Painting a blade black of the wind turbine can reduce bird deaths by over 70 percent Ecology and Evolution

"One of the mitigation measures we tested was painting one of three rotor blades black. The expectation is that this design reduces so-called motion smear, making the blades more visible to birds," said Dr May, adding that the concept of motion smear reduction was derived from an experiment carried out in the U.S. in early 21st century.

Limitations of Study

While the experiment successfully reduced bird fatality, Dr May said further testing would be needed in different wind farms to establish the findings. He said the "efficacy may well be site and species-specific."

He further added that the team had received interest from the Netherlands and South Africa to conduct the study in their wind farms. The team would like to see wind farm developers adopt such measures to alert birds.

However, a similar technique already exists where the tips of the blades are painted in red to alert low-flying aircraft. Dr May wants to test that as well. "Any improvements (or co-benefits) of the design could be interest in further study. This does however not preclude implementation of the current design," he told the BBC.

Red tips
Tips of the wind turbines are painted red to warn aircrafts Pixabay

AI Birdwatcher for Solar Farms

In the U.S., apart from wind farms, another clean energy producer solar farm too is responsible for bird deaths. Over 140,000 bird carcasses are found at solar farms each year in the U.S. alone. The number could be more than that as utility companies can't keep a bird watcher just to see the avian species crash to death.

To understand the reason, a similar study is being conducted at solar farms. Researchers are developing an artificial intelligent (AI) bird watcher that could monitor the bird deaths and help them find out a solution.