# Are windmills bad for birds? **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [March 4, 2013, 4:14pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005 "2013-03-04T16:14:41Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![ellieswan](https://avatars.discourse-cdn.com/v4/letter/e/df705f/32.png) [@ellieswan](https://boards.straightdope.com/u/ellieswan)\ **Post date:** [March 4, 2013, 4:14pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/1 "2013-03-04T16:14:41Z")
You answered a question regarding windmills and weather patterns. I heard from a scientist friend of mine that windmills are terrible for migrating birds. How bad is that problem? Are windmills going to create more problems than they fix, by killing off bird species? ---
**Author:** ![Procrustus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/procrustus/32/2994_2.png) [@Procrustus](https://boards.straightdope.com/u/Procrustus)\ **Post date:** [March 4, 2013, 4:17pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/2 "2013-03-04T16:17:35Z")
apparently, it was more of a problem with older designs. Eco response [here.](http://www.treehugger.com/renewable-energy/common-eco-myth-wind-turbines-kill-birds.html) ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [March 4, 2013, 4:40pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/3 "2013-03-04T16:40:15Z")
It’s about time we finished the job the Cretaceous meteorite started: fucking flying dinosaurs! ---
**Author:** ![cochrane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cochrane/32/10441_2.png) [@cochrane](https://boards.straightdope.com/u/cochrane)\ **Post date:** [March 4, 2013, 6:16pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/4 "2013-03-04T18:16:43Z")
I assume the O.P. is referring to this column: [Will wind power change the weather?](http://www.straightdope.com/columns/read/2984/will-wind-power-change-the-weather) ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [March 5, 2013, 6:01pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/5 "2013-03-05T18:01:07Z")
You know what’s bad for birds? Cats. It’s hard to find good numbers, since many websites have an agenda, but the American Bird Conservancy site says [cats kill hundreds of millions of birds per year](http://www.abcbirds.org/abcprograms/policy/cats/index.html) in the US. By comparison, they attribute [440,000 deaths to windmills](http://www.abcbirds.org/abcprograms/policy/collisions/wind_developments.html), and [project 1 million per year](http://www.wbez.org/blogs/chris-bentley/2013-01/cats-kill-billions-birds-each-year-study-says-105233) if windmills increased to produce 20 percent of the US electricity. (Presumably they’re assuming careful placement and advancements in preventing windmill bird deaths, like in **Procrustus** ’s link, in the later number.) Now they’re not unbiased, but I’d at least expect those numbers to be biased in the same direction. For another take, [this site claims](http://reneweconomy.com.au/2012/want-to-save-70-million-birds-a-year-build-more-wind-farms-18274) windmills actually lead to fewer bird deaths, compared with other sources. They’re not unbiased either, but their point that you’d have to look at the net difference in bird deaths is valid. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [March 5, 2013, 6:11pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/6 "2013-03-05T18:11:10Z")
I won’t dispute that some birds are killed by flying into a windmill but that’s true about all structures. Some people seem to think windmills are spinning around at high speeds like whirling death propellers. But here’s a [video](http://www.youtube.com/watch?v=kismPgzNCqQ) of one actually in operation. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [March 5, 2013, 9:06pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/7 "2013-03-05T21:06:04Z")
> [@Little\_Nemo](#): > > I won’t dispute that some birds are killed by flying into a windmill but that’s true about all structures. Some people seem to think windmills are spinning around at high speeds like whirling death propellers. But here’s a [video](http://www.youtube.com/watch?v=kismPgzNCqQ) of one actually in operation. And [here’s](http://www.youtube.com/watch?v=sbCs7ZQDKoM) a video of a whirling death propeller :). But yes: cats, power lines, windows, cars, and a few other sources utterly dominate the bird death tally. See [here](http://en.wikipedia.org/wiki/Environmental_impact_of_wind_power#Birds) for a chart. ---
**Author:** ![moriah](https://avatars.discourse-cdn.com/v4/letter/m/b2d939/32.png) [@moriah](https://boards.straightdope.com/u/moriah)\ **Post date:** [March 5, 2013, 11:50pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/8 "2013-03-05T23:50:25Z")
> [@Little\_Nemo](#): > > I won’t dispute that some birds are killed by flying into a windmill but that’s true about all structures. Number of birds I’ve witnessed killed by a windmill: 0 Number of birds I’ve witnessed killed by a pane of glass: 5 ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [March 7, 2013, 1:55pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/9 "2013-03-07T13:55:32Z")
Windmills _[are](http://en.wikipedia.org/wiki/Environmental_impact_of_wind_power#Bats)_ bad for bats, however, and I doubt cats exert a lot of pressure on bat populations, so the effect is proportionately more pronounced. And bat populations are under a lot of stress right now. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [March 7, 2013, 3:43pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/10 "2013-03-07T15:43:53Z")
> [@Sailboat](#): > > And bat populations are under a lot of stress right now. Property taxes are going up and there’s been talk of lay-offs. ---
**Author:** ![Kolak\_of\_Twilo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kolak_of_twilo/32/73_2.png) [@Kolak\_of\_Twilo](https://boards.straightdope.com/u/Kolak_of_Twilo)\ **Post date:** [March 7, 2013, 4:16pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/11 "2013-03-07T16:16:34Z")
> [@Dr.Strangelove](#): > > But yes: cats, power lines, windows, cars, and a few other sources utterly dominate the bird death tally. See [here](http://en.wikipedia.org/wiki/Environmental_impact_of_wind_power#Birds) for a chart. So, the lesson I should take away is we need to develop wind turbines that kill more _cats_, thereby protecting bird populations. Did I get that right? ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [March 7, 2013, 8:06pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/12 "2013-03-07T20:06:09Z")
> [@Sailboat](#): > > Windmills _[are](http://en.wikipedia.org/wiki/Environmental_impact_of_wind_power#Bats)_ bad for bats, however, and I doubt cats exert a lot of pressure on bat populations, so the effect is proportionately more pronounced. Depends upon where the bats live. When I was growing up, someone moved bats into our neighborhood to help fight insects. Our cat was particularly devestating to that population. One summer I would regularly come out in the morning to 2 or 3 fresh dead bats on the porch. Thanks. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [March 7, 2013, 8:09pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/13 "2013-03-07T20:09:23Z")
> [@Sailboat](#): > > And bat populations are under a lot of stress right now. > [@Little\_Nemo](#): > > Property taxes are going up and there’s been talk of lay-offs. Well, that and [they can’t keep their noses clean](http://en.wikipedia.org/wiki/White_nose_syndrome). ---
**Author:** ![Michael63129](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@Michael63129](https://boards.straightdope.com/u/Michael63129)\ **Post date:** [March 7, 2013, 8:27pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/14 "2013-03-07T20:27:58Z")
> [@Little\_Nemo](#): > > I won’t dispute that some birds are killed by flying into a windmill but that’s true about all structures. Some people seem to think windmills are spinning around at high speeds like whirling death propellers. But here’s a [video](http://www.youtube.com/watch?v=kismPgzNCqQ) of one actually in operation. Keep in mind the relative size of a typical wind turbine, which can be [over 100 meters in diameter](http://www.terramagnetica.com/wp-content/uploads/2009/08/size.jpg); in that video, I count 2.5 revolutions in 11 seconds, which means that the tips of the blades are moving at 71.4 meters/second if it is 100 meters across (circumference 314 meters). That’s 160 mph, and 80 mph at half the blade length. Oh yeah, the blades alone can weigh [dozens of tons](http://www.wind-watch.org/faq-size.php), so getting hit by one is **much** worse than getting hit by a car. Although the blades are still moving relatively slowly and don’t cover much area, which helps prevent impacts. ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [March 8, 2013, 12:04am UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/15 "2013-03-08T00:04:36Z")
> [@Michael63129](#): > > Keep in mind the relative size of a typical wind turbine, which can be [over 100 meters in diameter](http://www.terramagnetica.com/wp-content/uploads/2009/08/size.jpg); in that video, I count 2.5 revolutions in 11 seconds, which means that the tips of the blades are moving at 71.4 meters/second if it is 100 meters across (circumference 314 meters). That’s 160 mph, and 80 mph at half the blade length. My Wikipedia link above contains this assertion, as well: > [@](#): > > Recent research shows that bats may also be killed when suddenly passing through a low air pressure region surrounding the turbine blade tips.[57] ---
**Author:** ![moriah](https://avatars.discourse-cdn.com/v4/letter/m/b2d939/32.png) [@moriah](https://boards.straightdope.com/u/moriah)\ **Post date:** [March 8, 2013, 5:27am UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/16 "2013-03-08T05:27:29Z")
> [@Kolak\_of\_Twilo](#): > > So, the lesson I should take away is we need to develop wind turbines that kill more _cats_, thereby protecting bird populations. > > Did I get that right? I’m tying pieces of strings to the end of my windmill propellers right away. ---
**Author:** ![fifty-six](https://avatars.discourse-cdn.com/v4/letter/f/5daacb/32.png) [@fifty-six](https://boards.straightdope.com/u/fifty-six)\ **Post date:** [March 8, 2013, 6:17am UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/17 "2013-03-08T06:17:53Z")
I don’t know much about biology or animal rights but is the number of birds killed even meaningful? Is it more important to measure the impact of windmills on the sustainability of the population? If the populations remain healthy then aside from poor little birdy does it matter much? Some managed fisheries kill milions of fish yet the populations are not in danger. Same with hunting certain animals. So aside from pure numbers are windmills bad for healthy bird populations? ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [March 8, 2013, 7:50pm UTC](https://boards.straightdope.com/t/are-windmills-bad-for-birds/652005/18 "2013-03-08T19:50:07Z")
Raptors (i.e. large birds) are at risk because their breeding rates are lower. They’re also at greater risk from power lines because they are large enough to bridge between lines and cause a short. One particular wind farm was a risk because it rested in a valley along a condor migration corridor, so it poses a larger risk to that population than wind farms in general.