I've been collecting information on this topic for a while, and yesterday, I sat down to write a post that would clarify the question of the impacts of windmills on bird populations. It turns out, however, that I was totally unsatisfied with the available data on everything from windmills to building strikes to cats, so instead I wrote a post making that very point: We really have no idea. This is an interesting and important problem, though, so it is worth having a conversation about.
The post is here: "How many birds are killed by windmills and other green energy projects?"
Greg, just as it's unfair (even misleading) to present risks and dangers associated with nuclear power without drawing parallels with its alternatives (as Petr Beckmann did in his book, 'The Health Hazards of NOT Going Nuclear'), should we not *also* compile statistics of how many birds are killed by non-green energy projects?
Granted, this data may also be hard to come by, but we wouldn't want to support the contention that it's only windmills that are threatening birds, and if we only go back to burning coal and drilling for petroleum then all of bird-dom would be safe and secure.
I rather think it's the other way around (especially considering habitat destruction).
Yes, I agree.
Ironically, this data (on non-green energy sources' impact on birds) IS very hard to come by, because wind energy has been studied far more intensively than its fossil fuel and nuclear competitors. Greg, could you say a bit more about why you are not satisfied with the wind statistics? I know quite a bit of effort has gone into developing them, so I'm curious.
I think the more important takeaway is that if we are building energy that kills birds, we need to build it better. The best part is, it can be done. Designs are testing in Alameda County / Altamont Pass right now that are very promising.
Tomgraywind: I have a similar problem with wind stats as I do with the bird stats. The "best study" is a metastudy of a lot of a far less than ideal data set. In this case the metastudies serve to carve out the really bad numbers, and to get a rough idea of what *might* be happening. Loss et all carve a range of estimates from 10K to 573K down to 140K - 328K. The fact that the estimate they actually come up with is essentially the same as the total unfiltered data set tells us something. It is a good start but it isn't that good.
The second problem with wind is that there are rapid changes in numbers of turbines, placement, and design so estimating bird mortality with the crop of windmills up to the end of some study period (so, say, mid 2013 at best) is like estimating safety in vehicles today using vehicles designed and built before, maybe, airbags (or maybe not that bad, but you get the point).
I am probably going to do something in more detail about both Loss et al on windmills and the cat study in the future. At this point, though, the overall effort involved does not seem to promise a large return.
The same basic problem applies, by the way, to all of the other numbers. All we really have are large order of magnitude guesses, and for each kill category we have very little consideration of either a) which subset of birds, by species or likely independent survival, is affected and b) adaptation. (for an interesting example of adaptation, see this: http://10000birds.com/a_new_case_study_of_natural_selection_in_birds.htm )
Here is a portion of the opinion of the Royal Society for the Protection of Birds on cat predation.
"Despite the large numbers of birds killed, there is no scientific evidence that predation by cats in gardens is having any impact on bird populations UK-wide. This may be surprising, but many millions of birds die naturally every year, mainly through starvation, disease, or other forms of predation. There is evidence that cats tend to take weak or sickly birds.
We also know that of the millions of baby birds hatched each year, most will die before they reach breeding age. This is also quite natural, and each pair needs only to rear two young that survive to breeding age to replace themselves and maintain the population.
It is likely that most of the birds killed by cats would have died anyway from other causes before the next breeding season, so cats are unlikely to have a major impact on populations. If their predation was additional to these other causes of mortality, this might have a serious impact on bird populations."
Badly sited and constructed wind turbines threaten individual birds. Fossil fuels threaten entire bird populations. The arguments made to exemplify the danger posed by turbines usually, almost invariably mention the Altamont Pass, and neglect to mention that the turbines there were put up before there was any awareness of a potential problem, and that the wind industry now seeks to avoid those early mistakes. The persons who tend to focus on turbines and bird mortality tend to ignore the consequences of continuing to use an energy system based on fossil fuels (as well as ignoring the finite character of those fuels), while they at the same time use whatever arguments they can to belittle already existing renewable energy technologies.
Denmark has good wind resources. In the first six months of this year 41.2% of our electricity came from wind. The Danish Energy Agency recently found that onshore wind was the least expensive way to add new electricity generation, with offshore wind in second place. The policy here has been to replace smaller, older turbines with larger, more efficient ones, so the result has been more energy production without a commensurate increase in the number of turbines, and without leaving a greater footprint on the landscape. Offshore wind has better resources, enables the use of larger turbines, and has become a more important contributor to electricity production. To the best of my knowledge, bird mortality has not been an issue here.
We are just finishing a LIFE project on Saker Falcons and one point was to find out the relationship between Sakers and wind farms. Based on the results, we produced a guideline for authorities authorising wind farm development projects. It is not scientific at all (we have not published our results yet), but I can send that guideline, if anyone interested.
An important finding is that large scale wind farm development projects simply take away habitats from birds, and that 'silent danger' is much bigger for bird species on population level than the risk of collision. At least, in this part of the world.
Bats may be more of a problem
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