Wind Farms: Bird Killers?

[Update: after some feedback on Twitter, and in the comments  I should point out the main objection to the Spectator article I refer to. I probably didn’t do a good job making it clear originally. The piece claims wind turbines are an extinction threat for many species. The “threat status” assessments of the species the article refers to indicate that this is probably not the case.]

Wind turbines kill birds and bats. A rather stark and provocative sentence, yet somewhat uninformative. This week’s Spectator however has an article which goes somewhat further. Written by Clive Hambler, of Oxford University, it starts like this:

Wind farms are devastating populations of rare birds and bats across the world, driving some to the point of extinction. Most environmentalists just don’t want to know. Because they’re so desperate to believe in renewable energy, they’re in a state of denial. But the evidence suggests that, this century at least, renewables pose a far greater threat to wildlife than climate change.

Now, the initial response to it on Twitter was for some climate change “skeptics” and a few nuclear advocates to leap in to action and say it was a clear condemnation of how bad wind farms are for wildlife. Reading tweets such as this from James Delingpole probably is enough to make sane people dismiss the story:

Great Speccie article by Oxford ecologist Clive Hambler on the devastation wind farms wreak on birds and bats http://t.co/v7RpwIJ2

— James Delingpole (@JamesDelingpole) January 3, 2013

Now, if James Delingpole describes something as great my gut instinct is to conclude that is probably rubbish. Yet, George Monbiot suggests that the issues raised in the piece must be taken seriously:

This, in @spectator, is not the usual drivel. Uncomfortable, but we shld take the issue seriously: http://t.co/yhM718Ez

— GeorgeMonbiot (@GeorgeMonbiot) January 4, 2013

So, should this piece makes us reconsider wind farms? Let’s begin with a little fact checking. The first claim about bird and bat deaths is this:

Every year in Spain alone — according to research by the conservation group SEO/Birdlife — between 6 and 18 million birds and bats are killed by wind farms.

As far as I can tell the claim has been made by SEO/Birdlife, however I cannot find an actual report anywhere, so the claim simply has to be taken on authority. Exactly what SEO/Birdlife concluded from this is not clear, but 6 to 18 million deaths sure sounds impressive. [Update: Anthony Hallam has pointed to the SEO/Birdlife report (the relevant stuff is on page 12 apparently). My Spanish is just about enough to order food on my occasional visits to Barcelona, so if any Spanish readers have views on it, enlighten me in the comments section.]

This leads me to the next claim:

And these figures may be conservative if you compare them to statistics published in December 2002 by the California Energy Commission: ‘In a summary of avian impacts at wind turbines by Benner et al (1993) bird deaths per turbine per year were as high as 309 in Germany and 895 in Sweden.’

A look through Google Scholar indicates that a) this study is not available to download anywhere, and b) was an “unpublished report.” By coincidence, or not, my search for the SEO/Birdlife report threw up a press release from “Save the Eagles International” in which they wrote the following:

Quoting from a California Energy Commission study: “In a summary of avian
impacts at wind turbines by Benner et al. (1993) bird deaths per turbine per year
were as high as 309 in Germany and 895 in Sweden.”

This press release was written by Mark Duchamp, who is according to the Spectator piece a colleague of Hambler’s. So, the best we can do for these two claims is read a press release from a group that appears to campaign against wind farms.

Let’s move one to the next claim:

In Australia, the Tasmanian wedge-tailed eagle is threatened with global extinction by wind farms.

It is true that this species (or more accurately subspecies) is threatened with extinction, but is it from wind farms? The Australian government website listing threats to species suggests that while wind turbines are a potential threat, most of the evidence suggests it is a very limited one.

Moving on:

In Spain, the Egyptian vulture is threatened, as too is the Griffon vulture — 400 of which were killed in one year at Navarra alone.

The Egyptian vulture does appear to be threatened by wind turbines, however given its wide geographic range, and number of other threats it face, it appears turbines are ab limited threat. Methods to reduce the mortality rate of the Griffon vulture by about 50% have been proposed, and it is important to note that this species is currently increasing in numbers throughout its geographic range, and is not regarded as being vulnerable.

Moving on again:

Norwegian wind farms kill over ten white-tailed eagles per year and the population of Smøla has been severely impacted by turbines built against the opposition of ornithologists.

The first thing to note here is that Norway gets close to 100% of its electricity from hydro-electric. In fact it has only used about 60% of its hydro potential. So, Norway is a bad country to choose as an example of wind farm impacts. This species is also not listed as vulnerable, however wind farms may pose a minor threat.

I could go on, but I won’t. Overall, it is quite clear that this article is an attempt to impress, and not inform, with numbers. This reaches its peak at towards the end:

Some studies in the US have put the death toll as high as 70 bats per installed megawatt per year: with 40,000 MW of turbines currently installed in the US and Canada. This would give an annual death toll of up to three million.

Now, I am going to confess that I probably know as little about bats as the average Spectator reader. Is three million bats killed per year a lot? It may or not be, but Hambler makes no effort to demonstrate that it is, relying instead on the reader being impressed by the large figure.

Let’s try to put these big numbers in to perspective. A recent Nature piece included a good summary of, and the uncertainties involved, in bird deaths due to various things humans do:

Looking at this it would seem that wind farms aren’t much more damaging to birds than many regular human activities. And if wind farms are bad, then it is probably high time that we engaged in widespread cat euthanasia.

Does this mean that wind farms should be a given a free pass? Absolutely not. It is clear that there are areas where wind farms will do significant damage to individual species. The correct response to this, however is not opposition to wind farms, but to treat wind farms on a case by case basis.

However, what has been missing from everything I have written above, and in the Spectator article, is a comparison of wind power with other forms of electricity generation. The choice is not between building a wind farm and not building it, but between building a wind farm and building something else. As Tom Webb writes here, UK nuclear power stations probably kill millions of fish each year. This number however should, like windfarm bird kills, should be put in context of other human activities, i.e. fishing. In fact, if you gave me a day, I could probably write an article about any power source to show that it has serious wildlife impacts, and even squeeze in a claim or two about millions of deaths to species.

I suspect that we really do not have a clear idea whether wind power is better or worse for wildlife than nuclear power, or any other source. However, if anyone disagrees with me, the comments section is all yours.

[Note: as was pointed out to me on Twitter and in the comments section I should have mentioned the position statements of major bird organisations. As far as I am aware none of them could be labelled “anti-wind farms.” The RSPB’s position is given here, and this quote is worth bearing in mind:

We are calling for a more strategic and long-term planning approach to wind development than is currently being taken. With the right strategy and planning safeguards, and with co-operation between developers and conservationists, renewable targets can be achieved without significant detrimental effects on birds of conservation concern or their habitats.

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[Update: a couple of people on Twitter reminded me of this excellent figure from David MacKay’s Sustainable Energy Without The Hot Air, which puts wind farm bird kills in context:

Figure 10.6. Birds lost in action. Annual bird deaths in Denmark caused by wind turbines and cars, and annual bird deaths in Britain caused by cats. Numbers from Lomborg (2001). Collisions with windows kill a similar number to cats.

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