Do Wind Turbines Kill Birds?

Sadly, global bird populations are in decline, according to numerous ornithological studies, and there are many culprits. Loss of wildlife habitat, overexploitation, and climate change are some leading causes. Although it is responsible for a relatively low number of bird fatalities, by comparison, wind turbines do play a role.

In the United States, scientists estimate that wind turbines are responsible for one million bird fatalities in the United States annually. However, this dwarfs when compared to other causes. 

Leading causes of bird fatalities in the United States:

  • Collisions with communication towers – 6.5 million
  • Power lines – 25 million
  • Pesticides – 67 million
  • Automobiles – 200 million
  • Windows – up to 1 billion
  • Cats – 1.3 to 4 billion

Wind turbines do kill birds, but wind power is also helping protect bird populations by slowing climate change, which poses an enormous threat to bird populations. Therefore, the best way to protect birds is by dilligently siting wind farms to mitigate bird collisions and using wind energy and other renewables to replace polluting fossil fuels.

Why do birds collide with wind turbines?

Unfortunately, numerous barriers and obstructions cover much of the planet and take a staggering toll on birds, whose populations are already declining at an alarming rate. It seems that the visual abilities of some birds is not good at detecting obstructions. 

Also, another factor may be motion smear, which makes rapidly moving objects appear blurry. For example, the wings of a hummingbird in flight are not very clear, but humans can intuit their existence, even if they do not clearly see them. One possible explanation for bird collisions is that the wind turbine blades are moving fast enough that birds do not see them.

In addition, wind turbine blades are commonly painted white. However, they can blend with the background, especially with clouds of a similar color. 

Is wind energy sustainable if it causes bird collisions?

Fossil fuels, in particular, have grave ecological effects. The environmental impact from extracting and burning oil, gas, and coal destroys wildlife habitat and pollutes the water and air. Then, building pipelines and transporting fossil fuels have been responsible for further contamination and wildlife destruction. However, every type of energy production has an environmental impact, even solar and wind energy. 

The manufacturing of solar panels requires extracting natural resources. Unfortunately, solar modules are costly and difficult to recycle into high-value goods. Therefore, solar panels are ending up in landfills, especially in countries that do not have laws prohibiting this practice. 

Despite issues with bird fatalities, there are many aspects of wind energy that make it particularly sustainable. Wind turbines need very little oil for maintenance, and most of the components are readily recyclable, except for the turbine blades. Unlike most power plants, wind farms do not require water, which helps preserve this precious resource. Also, wind turbines rely on the wind instead of fossil fuels and do not produce greenhouse gas emissions. Therefore, renewable energy, including solar and wind power, are critical for slowing climate change. 

In fact, climate change poses an ever-growing threat to birds. A report by the American Audubon Society estimates that more than two-thirds of North America’s bird species will be vulnerable to extinction due to range loss and altering migration patterns, according to the current warming trend of 3 degrees Celcius by 2100. Thus, dramatic and immediate action is needed to slow the warming trend to 2 degrees Celcius. 

For this reason, the American Audubon Society supports the wind energy industry because of its potential to reduce global greenhouse gas emissions and pollution that threaten birds. It also advocates for properly sited wind farms, that help reduce avian fatalities. “Audubon strongly supports wind energy that is sited and operated properly to avoid, minimize, and mitigate effectively for the impacts on birds, other wildlife, and the places they need now and in the future. To that end, we support the development of wind energy to achieve 100% clean electricity.”

One of the best ways to slow climate change is to quickly reduce global greenhouse gas emissions. Transitioning to clean energy sources, such as wind power and solar energy, while dramatically reducing the consumption of fossil fuels is critical to protecting wildlife populations.

“Fortunately, the global network of bird conservation organizations taking part in this study have the tools to prevent further loss of bird species and abundance,” Ken Rosenberg from the Cornell Lab, co-author of State of the World’s Birds. “From land protection to policies supporting sustainable resource use, all of it depends on the will of governments and of society to live side by side with nature on our shared planet.”

How can wind farm owners reduce bird fatalities?

Although proper siting of wind farms can reduce bird collisions, researchers are testing ideas for ways to warn birds that wind turbines are nearby. If effective and affordable, these actions are especially promising because wind farm owners can utilize them on existing wind farms that are already in operation.

Roel May, a researcher at the Norwegian Institute for Nature Research (NINA), and his team are investigating if painting one of the wind turbine blades black can help reduce avian collisions by reducing motion smear. The preliminary finds show that bird fatalities can be reduced by 70% from this relatively simple and cost-effective action. 

The idea is that painting turbine blades black help birds notice the turbines and correct their flight path accordingly. The study used a specialized team to paint by repelling onto the blades and painting them in mid-air. There are four wind turbines with painted blades and four without. Staff with trained dogs searched for bird carcasses around the wind project site for seven and a half years before the blades were painted and three and a half years after. Although the findings are very promising, eight turbines is a very small sample size. Therefore, more research is needed in this area, but some is already underway.

Researchers from the American Wind Wildlife Institute (AWWI), a nonprofit that brings scientists and the wind industry together to study and reduce wind energy’s impact on wildlife, are experimenting with deterrence systems that alert birds. 

“When you detect something that you think might be an eagle within a certain distance of a turbine, you emit sounds that will first alert the bird,” says Taber Allison, director of research at AWWI. “If the bird keeps coming, you send a second signal that—you know, the hope is it will persuade the bird to change its flight path.” The turbines will warn the birds to keep their distance, and an AWWI report estimates this method could reduce collisions by 33% to 53%.

How can wind energy help protect bird populations by reducing pollution?

Conserving wildlife habitat and diligent placement for wind turbines is critical for maintaining healthy bird populations. However, wind energy can also help preserve the environment by displacing the use of polluting fossil fuels. 

For example, surface coal mining can devastate ecosystems and contaminate water and land. Large amounts of water are pumped from surrounding aquifers which diverts is from other critical uses like agriculture and for wildlife. Bulldozers and excavators remove top soil to access coal deposit. Large amounts of rock are piled up, which disturbs plant and animal communities and contaminates water supplies due to heavy metals and sometimes toxic substances. 

Likewise, oil and gas extraction can have a large impact on water quality and wildlife populations. Now that most of the oil reserves that are easiest to access have already been depleted, oil and extraction is largely in remote areas far below the earth’s surface. This means that drilling is more difficult and the oil and gas needs to be transported longer distances, increasing the risk of spills. 

Oil pipeline leaks and spills can devastate birds communities because the added weight of oil makes it difficult to fly and requires more calories.  Also, seabird populations are particularly vulnerable to oil spills, because the oil inhibits birds’ ability to repel water and conserve heat, which causes hypothermia.

“Feathers are the most important feature of a bird,” says Ivan Maggini, lead author of a study published in the Journal of Experimental Biology and an ornithologist at the University of Western Ontario. “They allow birds to jump off the ground and soar into the air, plunge at incredibly high speeds, and even shoot in and out of water. But these feats are only possible if a bird’s feathers are unencumbered.”

Therefore, electrifying transportation and transitioning to clean energy is essential for protecting bird populations and wildlife from the impacts of polluting fossil fuels. As wind energy deployment increases, it displaces polluting forms of energy, like coal and oil.

Do wind farms impact birds in other ways?

Yes, there are other impacts on wildlife populations besides just collisions with wind turbines, just like any form of development has an impact on habitat. For example, transmission and distributions lines are needed to carry the electricity from wind farms to population centers. Unfortunately, birds can have fatal collisions or be electrocuted from power lines. 

Likewise, the construction of wind farms can result in habitat loss on the project site. As wind turbines become more efficient, this helps minimize the impacts on landscapes proportionate to the power production. However, the single greatest threat to wildlife populations is climate change and renewable energy deployment is essential for minimizing it.

Do wildlife organizations support wind energy?

Yes, there are numerous wildlife organizations across the globe that strongly support responsible wind energy deployment because of its ability to promote wildlife conservation and even racial equality while preventing pollution.

For example, the Royal Society for the Protection of Birds (RSPB) states on its website, “Climate change poses the single greatest long-term threat to nature, and the RSPB recognises the essential role of renewable energy in addressing this challenge.”

The World Wildlife Fund (WWF) EU takes a similar stance and states, “If we are to prevent dangerous climate change then we need move to 100% sustainable renewable energy as soon as possible…But renewables still face unfair competition from fossil fuels, often burnt in plants that don’t pay the real price of the carbon pollution they cause. The EU has set a 32% target for renewable energy by 2030, but this is not enough.” 

The National Audubon Society, an American non-profit environmental organization dedicated to conservation of birds and their habitats, also supports responsible wind energy deployment. “Top scientific experts from around the world, including Audubon’s own scientists, agree that the effects of climate change are happening now and will get worse if warming is not limited to 1.5 degrees C. Expansion of renewable and carbon-free energy is an essential piece of meeting this goal, and wind power is currently one of the most economically competitive forms of renewable energy. Beyond the climate impacts, wind power also avoids air pollution caused by fossil fuel combustion that disproportionately affects low-income communities and communities of color.”

In the United States, there are numerous examples of the pollution from oil and gas operations disproportionately impacting African American neighborhoods. Sadly, this pollution can have grave health effects on these communities. 

How can wind farm siting help protect birds?

Altamont Pass Wind Farm in Northern California, United States, is one of the oldest wind parks in the country. Even though wind farms have become more prevalent today than when Altamont Pass Wind Farm was construted, it still has one of the largest concentrations of wind turbines globally. Sadly, it is responsible for the deaths of numerous birds, and scientists estimate that Altamont Pass kills 880 to 1,300 birds of prey annually,  including up to 116 golden eagles, 380 burrowing owls, and 300 red-tailed hawks.

According to the Center for Biological Diversity, “The bird kill fiasco at Altamont Pass is a result of poor planning that allowed wind turbines to be built along a major raptor migration corridor in an area with high wintering concentrations of raptors and in the heart of the highest concentration of golden eagles in North America.”

Before constructing a wind farm, it is critical to consider the impacts on birds and other wildlife. 

According to the United States Office of Efficiency and Renewable Energy’s website, “Project developers should identify and avoid locations with favorable habitat characteristics to limit potential negative impacts to sensitive species, such as low-level flight paths, areas with high prey density, maternity roosts, winter ranges, nesting sites, migration stopovers or corridors, and wetlands.” 

Wind farm developers can collaborate with wildlife experts to determine which sites are most suitable for wind farms to protect bird populations. Likewise, policies that make it easier to obtain permits in “low impact” areas will help advance the wind energy industry while protecting key species.

Research into the impacts of wind farms on wildlife is advancing thanks to numerous scientific studies. As a result, there is far more information available to wind farm developers on how to reduce the effects of a wind farms on wildlife populations. For example, researchers in Europe are using tracking devices to determine which potential and existing wind farms would be most problematic for birds. Such information can help balance the need between preventing bird collisions and expanding clean energy production.

Do all wind farms have an issue with bird collisions?

Although some wind farms, like Altamont Pass have earned a negative reputation for bird fatalities, some wind energy developers have had very different experiences while operating wind parks. Mark Wilson, technical director of WindCare Limited, one of the United Kingdom’s latest

wind turbine servicing companies, has visited thousands of wind turbines over the last twelve years. 

“I have never seen or been made aware of any dead birds or bats at the foot of or even in the vicinity of any wind turbines,” explains Wilson in an interview with Wind Turbine Magazine.

“To put this into context, we looks after hundreds of wind turbines— all in rural locations throughout the whole of the United Kingdom—which we visit at least twice a year to perform scheduled services.”

In fact, he has actually found two bird nests that were constructed within the wind turbine nacelles, which sits atop the tower adjacent to the rotor and houses all the generating components of a wind turbine. “Most birds do not seem to have a problem with avoiding the moving blades or shafts and actually nest inside them,” says Wilson. He now installs mesh on the nacelles and hubs to avoid birds nesting on operational wind turbines. 

“On two occasions I have personally removed almost two full buckets of nesting material. This

happened twice before we installed mesh to stop the birds entering the nacelle. As you can imagine, there must have been a large amount of visits to the turbine to make two nests

this size, each time avoiding the rotating blades and other moving parts. The nest I removed was

about 10 inches deep.”

Such experiences highlight that the prevalence of bird collisions at wind farms varies widely between project sites and that the existence of wind turbines isn’t synonymous with bird fatalities. 

Are smaller or bigger wind turbines better for birds?

Although there are numerous factors to consider when reducing avian mortalities, one critical consideration is the sweep area of the wind turbine blades. This is the area covered as a wind turbine rotates around in a circle. 

Therefore, turbines with longer blades have a larger sweep area. Conversely, wind turbines with shorter blades have a smaller sweep area. However, a larger sweep area allows the unit to capture more kinetic energy. Therefore, larger wind turbines have a bigger area that can cause bird collisions. Still, they produce proportionately more energy, which reduces the total amount of wind turbines needed to generate the same amount of energy.

“Not all turbines are equal,” says Tim Norman, U.K. director, and vice president for offshore at Niras, an international engineering consultancy. “The bigger you get, the more efficient they are. So they need less swept area for the same energy generation.”

Thus, one large wind turbine can result in fewer bird collisions than several large ones. One big trend in wind energy is that wind turbines are getting bigger and taller because this increases energy production and is more economical. When wind developers retrofit existing wind farms, they often replace two or three older and smaller wind turbines with one larger one, which has similar energy yields and can help reduce bird collisions.

Are offshore wind turbines harmful for birds?

Both onshore and offshore wind projects can be harmful to birds, but there are ways to help protect them. Many seabirds have an affinity for the surface of the water because they either dive down for food or they are surface feeders. Therefore, wind turbines with shorter towers that are closer to the sea surface can cause more bird collisions that turbines with longer towers. In particular, increasing the air gap or the space between the surface of the water and the lowest reaches of the turbine blades is essential.

However, offshore wind turbines tend to be very large and to have tall towers already, like  the 14 megawatt Siemens Gamesa 14-222 DD. It has a rotor diameter of 222 m and the hub height is site specific. Yet, the dimensions of offshore wind turbines continue to increase, making units with taller hub heights and a bigger air gap more likely in the future

Are bird populations at risk?

Sadly, the populations of numerous bird species are in decline. According to the study, the study, “State of the World’s Birds,” 48% of existing bird species are known or suspected of undergoing population declines. The populations for 39% of species are stable. A mere 6% show increasing population trends, and the status of 7% remains unknown. 

“We are now witnessing the first signs of a new wave of extinctions of continentally distributed bird species,” said Alexander Lees, senior lecturer at Manchester Metropolitan University in the United Kingdom and also an associate researcher at the Cornell Lab of Ornithology. “Avian diversity peaks globally in the tropics and it is there that we also find the highest number of threatened species.”

Certainly, the world’s bird populations need protection. Because there are numerous threats, many approaches are needed to preserve their populations. Designing windows that prevent bird collisions, reducing the population of outdoor cats, using pesticides that are safer for birds, siting wind turbines responsibly, and curbing climate change can all help. Collaborations with wildlife experts, policymakers, manufacturers, wind farm developers, non-profit organizations, and community stakeholders are critical for thriving bird populations.

Edward Rivis

I co-own a fleet of wind turbines, and I'm passionate about renewable energy and it's critical role in helping avoid irreversible damage to our planet.

Recent Posts