1,000s Of Bats Die Every Year From Wind Turbines: Can We Save Them?

The answer is “Yes”: it’s possible that new technology could save the bats.

Care2 has noted previously that communication towers kill nearly 7 million birds every year as they cross the Americas, migrating south, and that wind turbines with retractable blades could cut down on the number of birds killed by these turbines.

But what about the thousands of bats killed by wind turbines?

Dead bats are turning up beneath wind turbines all over the world. Bat fatalities have now been documented at nearly every wind facility in North America where adequate surveys for bats have been conducted, and several of these sites are estimated to cause the deaths of thousands of bats per year.

The mystery of why bats die at turbine sites remains unsolved. Is it a simple case of flying in the wrong place at the wrong time? Are bats attracted to the spinning turbine blades? Why are so many bats colliding with turbines compared to their infrequent crashes with other tall, human-made structures?

To work on this problem, engineers and bat biologists are coming together this summer at a wind farm in Wisconsin to field-test a potential fix. They’ll attach ultrasonic microphones to four or five turbine nacelles to record the high-pitched squeaks and clicks bats emit for navigating and locating prey.

From spectrum.ieee.org:

Based on the data collected there and at 40 other wind installations, software developers will create a predictive model that also factors in meteorological information like wind speed, temperature, and precipitation. The model will yield a probability score that indicates the risk to bats at the site at any given time. When the risk is high—meaning there are likely many bats present—the utility operator will be able to shut down the turbines and then bring them back up when the risk is low.

“This project is really focused on trying to reduce bat mortality at wind farms while at the same times maximizing electricity production,” says John Goodrich-Mahoney, a senior project manager at the Electric Power Research Institute (EPRI), the sponsor of the field test, which runs through next year. “How do you balance those two needs?”


The economic impact of losing so many insect-eating animals is staggering: A study published in Science last year estimated that bat deaths could lead to annual agricultural losses in North America of more than US $3.7 billion.

It was in 2003, as biologists searching for dead birds at a wind farm in West Virginia noticed hundreds of dead bats, that wind turbines’ deadly impact on bats came to light. Scientists concluded that 1400 to 4000 bats were being killed there each year.

Since then, dozens of studies throughout North America and Europe have confirmed and refined the finding. It seems that most bats are killed when the turbine blade strikes them, but some may also succumb to the rapid pressure change they experience close to the turbine, which causes their hearts and lungs to burst.

Other options have been proposed to solve the problem: several years ago, a project sponsored by Bat Conservation International looked at whether ultrasonic “Boom boxes” mounted on wind turbines could deter bats. Another study, by Barry Nicholls and Paul Racey at Aberdeen University in Scotland, considered radar as a bat deterrent.

But this one looks the most promising. Let’s hope that the engineers and bat biologists in Wisconsin will be successful.

Related Stories

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Wind Turbines With Telescopic Blades, Catching The Breeze

Photo Credit: Sammy & Johnny


Diane L.
Diane L.2 years ago

Interesting theory, Larry. I wonder if there can be some kind of protective netting put around the turbine blades to prevent bats and/or birds from being drawn in or having any contact from them? It might be costly, but on the other hand, we DO need to protect all aspects of the environment when we install such things. I definitely am in favor of harnessing wind power, and think the positives offset the negatives.

I have a large fan that circulates (rotates 180 degrees) and it has a sort of "cage" to protect one from touching the fan's blades. Of course the "cage" is only to prevent human hands or a cat or dog from touching the blades and anything around those huge wind turbine blades would have to be much smaller "openings", but I think it could be done.

Larry Lorusso
Larry Lorusso2 years ago

Bats are attracted by insects which are drawn by the warmth of the open areas that are made when installing wind turbines in mountainous areas. While the bats are killed by impacts with the turbine blades, also due to the delicate lung structure of bats lungs implode from the low pressure created from the spinning blades. It's similar to the bends that divers experience. Often the bodies of bats I've found at these projects don't seem to have any blunt trauma. Here in Massachusetts Little Brown Bats are listed as endangered. In some roosts mortality rates are 100% and White Nose Syndrome has been devastating. Remember when dealing with the lesser of two evils, you are still dealing with evil. Around here most of the bats are gone. It would be a shame if bats are no longer with us as they have an important role. Another aspect of IWT's around here is the destruction to the environment, such as blasting, thousands of trees cut and shredded, swamps eliminated and the ridges filled in, resulting in altering watersheds, often the sources of pristine streams.

Diane L.
Diane L.3 years ago

Have a nice night, Neal.

Neal King
Neal King3 years ago

Diane L.:

So you're claiming that the Daily Mail just made up the 230,000 bats in the UK?

Diane L.
Diane L.3 years ago

Wrong, Neal, I read it. What you fail to understand is that birds nest in trees, and they also forage on the ground for seed. Robins and other similar species hop around on the ground to eat insects and worms. Bats do not do so. Again, try to get your facts about each species correct and take your obvious dislike for felines to a more appropriate discussion.

Reading back in this discussion, you have repeatedly popped in accusing others of not reading the article, when it's you who digress and want to change the topic.

Neal King
Neal King3 years ago

Diane L.:

I guess you didn't read to the END of my previous note, which was:
"But cats also targeted many bats, which are very slow to reproduce, possibly killing 230,000 a year across the country."

That is 230,000 BATS for the UK.
If you consider that they estimate 55 Million birds for the UK, but the US estimate for birds is about 2 Billion (36 times), then it would not be unreasonable to also guess that they get 36 * 230,000 = 8.4 Million bats in the US.

Wrt cats not flying: That hasn't stopped them from killing birds. Where there's a will, there's a way...

Diane L.
Diane L.3 years ago

Yes, Neal, you finally got it right.......it's about BATS, not CATS. Cats are lethal hunters, and those of us who have them and love them know this. However, cats can't fly and if one understands that BATS usually reproduce in caves and under the eaves of houses or in very tall trees, it makes little sense to accuse cats of being responsible for the demise of very many of them. If a cat manages to catch and kill a bat, then the bat was probably ill.

I understand from your rantings against cats, that you probably are not a cat lover. That's fine and everyone is entitled to care or not care for whatever species, but at least try to take your hostilities against housecats to a more appropriate discussion. I also would highly disagree with the "stats" that you've posted. They're really taken out of context.

Yup, I have cats, including two that live outside, and one of them is quite "lethal" as a hunter. 30 - 40 "critters" a year might be an underestimation, but 99% of them are rodents, which is what he's here for.

BTW, bats live here and I find them fascinating. Not sure where they "live" as they only come out at night and are pretty high flying. None of my cats has caught one yet :)

Neal King
Neal King3 years ago

Oops, I forgot this was supposed to be about bats. Here's a report from the UK:

"Domestic cats are lethal hunters, killing at least 275 million other animals a year in Britain, a report showed today.

The apparently cuddly pets prey on a number of declining and endangered species, including water voles and dormice, said the Mammal Society.

The survey, called Look What the Cat Brought in, found that the average household cat caught or killed between 30 and 40 creatures a year.

With an estimated nine million pet cats in this country, the haul amounted to 200 million mammals, 55 million birds and 10 million reptiles and amphibians....

But cats also targeted many bats, which are very slow to reproduce, possibly killing 230,000 a year across the country."

(The "country" in this article is the UK; the US numbers would be a lot larger.)


Neal King
Neal King3 years ago

"Domestic cats kill many more wild birds in the United States than scientists thought, according to a new analysis. Cats may rank as the biggest immediate danger that living around people brings to wildlife, researchers say.

America’s cats, including housecats that adventure outdoors and feral cats, kill between 1.4 billion and 3.7 billion birds in a year, says Peter Marra of the Smithsonian Conservation Biology Institute in Washington, D.C., who led the team that performed the analysis. Previous estimates of bird kills have varied, he says, but '500 million is a number that has been thrown around a lot'."


Diane L.
Diane L.3 years ago

Really, Neal? Yeah, those danged flying cats around here truly are a nuisance.