Wind farms and abuse of statistics: bird edition

When "wind farms are dangerous" really just means "there are a lot of birds".

When dealing with large numbers, it helps to have an idea of the expected order of magnitude. That way, you can know whether it is merely the number which is large, or the thing it's describing as well.

For instance, if I tell you of a country with 140,000 people in long-term unemployment, it's rather important for you to know if I'm talking about the US (population 280 million) or Luxembourg (population 525,000).

That's a test a Spectator article, Wind farms vs wildlife, failed quite badly this week.

The author, Clive Hambler, is a lecturer in biological and human sciences at Oxford university, and quotes a number of statistics to demonstrate how dangerous wind farms are to wildlife. For instance:

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. They kill roughly twice as many bats as birds. This breaks down as approximately 110–330 birds per turbine per year and 200–670 bats per year. 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.’

Similar claims are made throughout. Apparently the annual death toll of bats in the US and Canada is "up to three million", "Norwegian wind farms kill over ten white-tailed eagles per year", and so on.

What is missing is any context through which we can examine these numbers. It might change our interpretation of the figures to know that:

Domestic and feral cats have also been considered a major source of anthropogenic-caused mortality with estimates near 100 million annual bird deaths [in the US].

Or that, on roads near wetlands in Canada:

223 birds were killed per mile per year.                                                                                            

Power lines in the US are estimated to kill:

…approximately 130 million birds per year.                                                                                                        

While we're banning things, we may want to keep an eye out for that scourge of the avian world, windows:

97.6 to 976 million bird deaths per year in the U.S. due to collisions with windows… based on an estimated 1 to 10 bird deaths per structure per year from a fatality study in New York.

All those figures come from a 2005 paper by the US Department of Agriculture.

In other words, even with the massive figures from Spain – figures which show deaths per turbine per year two orders of magnitude higher than equivalent figures cited in the above paper, which are based on an assumption that for every confirmed death, there's nineteen uncomfirmed, and which come from a set of guidelines which explicitly concludes wind farms are OK for birds if built correctly (pdf) –  wind farms kill fewer birds than cats, power lines, roads or windows. That comparison would have been rather useful to include in the original piece. With that in mind, the numbers in the piece become less a demonstration of the awesome mortality of wind farms, and more a confirmation that yes, there are a lot of birds in the world.


It's been pointed out on Twitter that I'm not comparing like to like. Spain is smaller than the US, of course. Thankfully, the USDA also estimates the number of birds killed by wind farms in America: between 20,000 and 37,000 a year. I let you draw your own conclusions from the discrepancy.

Wind Turbines in Spain. Photograph: Wikimedia Commons

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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How the shadow cabinet forced Jeremy Corbyn not to change Labour policy on Syria air strikes

Frontbenchers made it clear that they "would not leave the room" until the leader backed down. 

Jeremy Corbyn had been forced to back down once before the start of today's shadow cabinet meeting on Syria, offering Labour MPs a free vote on air strikes against Isis. By the end of the two-hour gathering, he had backed down twice.

At the start of the meeting, Corbyn's office briefed the Guardian that while a free would be held, party policy would be changed to oppose military action - an attempt to claim partial victory. But shadow cabinet members, led by Andy Burnham, argued that this was "unacceptable" and an attempt to divide MPs from members. Burnham, who is not persuaded by the case for air strikes, warned that colleagues who voted against the party's proposed position would become targets for abuse, undermining the principle of a free vote.

Jon Ashworth, the shadow minister without portfolio and NEC member, said that Labour's policy remained the motion passed by this year's conference, which was open to competing interpretations (though most believe the tests it set for military action have been met). Party policy could not be changed without going through a similarly formal process, he argued. In advance of the meeting, Labour released a poll of members (based on an "initial sample" of 1,900) showing that 75 per cent opposed intervention. 

When Corbyn's team suggested that the issue be resolved after the meeting, those present made it clear that they "would not leave the room" until the Labour leader had backed down. By the end, only Corbyn allies Diane Abbott and Jon Trickett argued that party policy should be changed to oppose military action. John McDonnell, who has long argued for a free vote, took a more "conciliatory" approach, I'm told. It was when Hilary Benn said that he would be prepared to speak from the backbenches in the Syria debate, in order to avoid opposing party policy, that Corbyn realised he would have to give way. The Labour leader and the shadow foreign secretary will now advocate opposing positions from the frontbench when MPs meet, with Corbyn opening and Benn closing. 

The meeting had begun with members, including some who reject military action, complaining about the "discorteous" and "deplorable" manner in which the issue had been handled. As I reported last week, there was outrage when Corbyn wrote to MPs opposing air strikes without first informing the shadow cabinet (I'm told that my account of that meeting was also raised). There was anger today when, at 2:07pm, seven minutes after the meeting began, some members received an update on their phones from the Guardian revealing that a free vote would be held but that party policy would be changed to oppose military action. This "farcical moment", in the words of one present (Corbyn is said to have been unaware of the briefing), only hardened shadow cabinet members' resolve to force their leader to back down - and he did. 

In a statement released following the meeting, a Corbyn spokesperson confirmed that a free vote would be held but made no reference to party policy: 

"Today's Shadow Cabinet agreed to back Jeremy Corbyn's recommendation of a free vote on the Government's proposal to authorise UK bombing in Syria.   

"The Shadow Cabinet decided to support the call for David Cameron to step back from the rush to war and hold a full two day debate in the House of Commons on such a crucial national decision.  

"Shadow Cabinet members agreed to call David Cameron to account on the unanswered questions raised by his case for bombing: including how it would accelerate a negotiated settlement of the Syrian civil war; what ground troops would take territory evacuated by ISIS; military co-ordination and strategy; the refugee crisis and the imperative to cut-off of supplies to ISIS."

George Eaton is political editor of the New Statesman.