girlborealis

Many wind energy facilities kill bats, sometimes in really high numbers. This occurs all around the world.

In North America, we recently estimated that from 2000-2011 between 840,000 and 1.7 million bats were killed at wind turbines across North America, the vast majority of which (~80%) were of just three species.

Because of this, bat biologists are pretty worried about the effect wind turbines are having on bats.

How's that?

Good questions!

1) because bats fly they need really efficient lungs, so the lungs of bats are really thin (to facilitate oxygen transfer to their blood) and really pliable. They also have balloon like lungs like all mammals do. The flow is tidal (in and then out)

2) birds have a different sort of lung that is much more rigid and uni-directional over the gas exchange membrane. Does that make sense?

3) my fav bat species is the hoary bat

4)I'd brew a stout...a big Russian imperial stout :)

The only effective mitigation we have so far is to shut turbines down in low wind speeds because the majority of bats are killed when wind speeds are low (<6m/sec or so). They have been numerous studies that have looked at this. Check out this publication. Or this one I did a few years ago. Shutting turbines down in low wind speeds has consistently been shown to reduce fatalities by at least 50%.

This is great, but if fatality rates of bats are really high, a reduction of 50% may not be sufficient to protect the bats, so we need more research to refine the techniques or come up with new ones.

There have been tests of an ultrasonic deterrent, but nothing available to date. Read more about it.

Frankly, it's been a tough decade to be a bat in North America.

This is hard question because we lack solid population size estimates for most species of bats, especially for the species being killed in large numbers by turbines (hoary bats, silver-haired bats, and eastern red bats).

Three species of bat have just been been put on Canada's endangered species list because of white nose syndrome (WNS) (the little brown, the tri-colored, and the northern myotis), but there are more species being killed by the fungus in the States. Yes we are worried that we may lose some from WNS, or at least losing them in areas where WNS is most prevalent.

In general, wind turbines are worse for species that are not being infected with WNS. However, there are some species that are affected by both (like little browns and tri-coloreds). It's hard to say if or when we'll lost any of the migrants, but the current fatality rates are alarming.

Bats live a long time and reproduce really slowly (1-2 pups a year), so it takes them a really long tie to recover from population declines. that's one of the big reasons bat biologists are worried.

I actually think that there isn't enough protection for bats, but this really varies by region. They are quite well protected throughout Europe, but in North America there is very little legislation that protects bats, unless they are endangered.