Why do wind turbines kill birds

Ever since the first commercial wind turbines came online in the 1980s, there have been people preoccupied by their negative impacts on the environment. Whether it be criticisms of turbines as blights on the landscape, scepticism at the complicated mineral requirements of the technology, or anger at noise produced by the blades as they turn, the anti-wind lobby has been fierce. 

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The wind power market has grown at a CAGR of 14% between 2010 and 2021 to reach 830 GW by end of 2021. This has largely been possible due to favourable government policies that have provided incentives to the sector. This has led to an increase in the share of wind in the capacity mix, going from a miniscule 4% in 2010 to 10% in 2021. This is further set to rise to 15% by 2030. However, the recent commodity price increase has hit the sector hard, increasing risks for wind turbine manufacturers and project developers, and the Russia-Ukraine crisis has caused further price increase and supply chain disruption. In light of this, GlobalData has identified which countries are expected to add the majority of wind power capacity out to 2030. Get ahead and download this whitepaper for more details on the current state of the Wind Power Market.

by GlobalData

One criticism of wind power that continues to draw significant attention is the number of birds killed by spinning blades. Former US President Donald Trump, for example, accused the technology of “killing all the birds”, while current president Joe Biden has been accused of a “great bird slaughter” by the US anti-renewables lobby – but just how dangerous is wind power for birds?  

With wind farms rapidly scaling up across the world, it is hard to find a measure of the number of birds being killed each year that will still be accurate, but Joel Merriman, a wind specialist at charity the American Bird Conservancy, modelled the death rate at the start of 2021. He accounted for the fact that many of the bird death studies were published earlier in the decade and the numbers will have increased since then. He also factored in that many deaths of smaller birds will escape the notice of studies. Merriman concludes that 1.17 million birds are killed by wind turbines in the US each year.

This is a lot of birds, but it is only 0.016% of the estimated 7.2 billion birds that live in the US. It is also significantly less than the 5–6.8 million killed each year by communication towers, the 60–80 million killed by automobiles, the 67–90 million killed by pesticides, or the 365 million to one billion killed by cats each year in the US, according to a study published in Nature.

Even if we adapt Merriman’s model to reflect the predicted increase in wind power across the US, as modelled by the US Energy Information Administration (EIA) in its outlook for 2021, turbine deaths come nowhere close to these figures. The 90% increase in wind power from 2021–50 envisaged by the EIA would see 2.22 million birds killed annually by mid-century. 

Of course, simply looking at the total number of birds killed fails to acknowledge that particular species may be disproportionately affected. Studies have shown it is often larger birds of prey, of which there are fewer in an ecosystem, that are more likely to fly into blades. The Royal Society for the Protection of Birds, a UK charity, warned at the start of 2021 that new offshore wind developments in the North Sea threatened one particular seagull, the kittiwake, as they headed to their feeding grounds. On the flip side, modelling of bird deaths fails to account for new designs and technologies, such as painting blades black or curtailing movement at certain times, which may help protect more birdlife in the future.

It is also important to maintain perspective on why the rapid development of wind power is taking place. A net-zero future may see wind turbines kill tens of millions of birds around the world each year, but climate change and unsustainable lifestyles are killing billions: the World Wide Fund for Nature estimates that species population sizes have declined by an average of 68% since 1970.

Free Report

The wind power market has grown at a CAGR of 14% between 2010 and 2021 to reach 830 GW by end of 2021. This has largely been possible due to favourable government policies that have provided incentives to the sector. This has led to an increase in the share of wind in the capacity mix, going from a miniscule 4% in 2010 to 10% in 2021. This is further set to rise to 15% by 2030. However, the recent commodity price increase has hit the sector hard, increasing risks for wind turbine manufacturers and project developers, and the Russia-Ukraine crisis has caused further price increase and supply chain disruption. In light of this, GlobalData has identified which countries are expected to add the majority of wind power capacity out to 2030. Get ahead and download this whitepaper for more details on the current state of the Wind Power Market.

by GlobalData

While there seems to be a never ending deluge of pessimism surrounding the climate change debate these days, there is plenty of cause for optimism as well. One of the biggest examples is how quickly renewable energy is growing as a power source in a vast number of countries.

The International Energy Agency last year reported that by the end of 2021, renewable energy will account for almost 30% of global electricity output. In most countries, renewable energy is now cheaper than energy generated by fossil fuels.

A large proportion of that energy is generated by wind farms, dotted all across the globe. Wind turbines stick out from the landscape in a way that solar panels, geothermal stations and hydropower dams don’t. Potentially as a result of this, they’re the form of renewable energy which has come under most public scrutiny.

While many complaints often concern the impact on local aesthetics or property values, there is one concern with genuine consequences for local wildlife: bird deaths.

The wind turbine-bird death debate is what’s known as a green-on-green conflict.

On one side, there’s the ongoing need for more renewable energy. On the other, if wind turbines do cause significant bird deaths, that could threaten some populations already under pressure from habitat loss, invasive species, and climate change itself.

Do Wind Turbines Kill Birds?

Short answer, yes. There’s more than enough evidence to suggest that birds (not to mention bats) are killed by windmills. It’s not really up for debate, but it’s also not really a pressing question. The better question is…

Do Wind Turbines Kill Birds? Are Wind Turbines A Significant Threat to Bird Species?

First of all, let’s address the aspect of this debate where the science is most firm – wind farms pale into insignificance as a threat to bird species compared to numerous other, more devastating threats. Invasive alien species, outdoor cats, being scooped up by fishers as bycatch, pollution, and yes, climate change. All are bigger threats to shorebirds than wind farms.

If you really want to help birds, you are far better off correctly disposing of plastic, cutting down meat consumption or keeping your cat indoors than campaigning against wind farms.

That being said, let’s forget those other threats for a moment and focus on wind farms. Many studies suggest that wind farms don’t seem to have a significant effect on local bird (or bat) numbers. However looking at one local population can limit our understanding of the big picture.

If a wind farm is smack bang in the middle of a migratory route, that could cause trouble. If a nearby population is already threatened by farming, invasive species or local land degradation, then that could also cause trouble.

The solution to these two scenarios is simple: watch where you put a wind farm. Most studies which focus on bird deaths generally advise against placing wind farms near already threatened populations or heavily fragmented habitats.

So Why Don’t We Do That?

The good news is that we already do! Immense levels of planning go into deciding the location of a wind farm, and most decision-making processes factor in nature reserves and nearby bird and bat populations. Many countries give buffer zones to breeding areas for different species of shorebirds, as well as to nature reserves.

However this often clashes with local populations, who either feel that local wind farms devalue their land, don’t recognise the benefits of cleaner energy, or are concerned about bird deaths. 

There are also unfortunately countries who don’t consider biodiversity as heavily when placing turbines. When these wind farms are placed in migratory corridors, that can have effects on populations hundreds of kilometres away.

So… Should We Stop Building Them?

No! The sad fact is that almost any form of energy production requires some land use. Hydropower dams are terrible for fish populations. Solar farms use a huge amount of land for solar capture. It’s worth noting that almost all of the studies which quantify bird deaths admit from the beginning that wind farms are a positive force in the world. The studies are usually not intended to demonise wind energy, but to help governments and industry to better plan locations for wind farms.

It’s also important to remember that while there is a lot of uncertainty surrounding what impact climate change will have on bird populations, we know it’s unlikely to be good.

Short-term changes in population make-up are much easier to recover from than huge, potentially permanent temperature changes and the associated ecosystem upheavals. Increased wind energy is an important solution to the climate crisis. 

There’s also a lot of exciting technological advancements pouring in from all over the world that can reduce bird deaths. Some of these advancements are ultra-modern, like the cameras capable of recognising birds and automatically slowing turbine rotation to dramatically lower collision likelihood. Others are simpler, like painting one turbine black to increase visibility.

As a last word, I just want to reiterate what I wrote at the start of this post. Are wind farms a problem for birds? Yes. Are they one of the biggest problems birds face? Not even top five.

But any threat to the planet’s biodiversity needs to be taken seriously these days, so I am thrilled to see the leaps in planning, logistics and technology that are constantly making wind farms more and more bird-friendly. I hope soon that the green-on-green debate around wind farms can end.

Sam Perrin, PhD

Climate Data Expert, Ducky AS

As well as being one of our climate data experts, Sam is also an avid science communicator and runs the blog Ecology for the Masses, where he and a team of international writers break the world of biodiversity and ecology for the general public. Check it out here!

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