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.

Photo: Getty Images
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The twelve tricks in George Osborne's spending review

All Chancellors use chicanery, and George Osborne is no exception.

There is no great shame to a wheeze: George Osborne is no more or less partial to them than other Chancellors before him. Politicians have been wheezing away since history began. Wheezes aren’t even necessarily bad policy: sometimes they’re sensible as well as slightly sneaky. And we shouldn’t overstate their significance: the biggest changes announced yesterday were described in a clear, honest and non-wheezy way.

But it’s fun to try to spot the wheezes. Here are some we’ve found so far.


  1. Give people less time to pay their tax bills. Yesterday the Chancellor announced tax rises that will raise, in total, a net £5.5bn in 2019-20. A sixth of that total – £900m – results from the announcement that, from April 2019, anyone paying Capital Gains Tax (CGT) on the sale of a house will have to cough up within 30 days. Has the Chancellor made a strategic decision to increase taxes to pay for public services? Not really – he’s just moved some tax forward from the subsequent year to help his numbers stack up, at the price of bigger hassle for people who are selling houses. Not necessarily a bad thing – but a classic wheeze.


  1. Dress up a spending cut as a minor bureaucratic change. The Treasury yesterday announced what sounds like a sensible administrative change to the Government’s scheme for automatically enrolling people into pensions: “to simplify the administration of automatic enrolment for the smallest employers in particular, the next two phases of minimum contribution rate increases will be aligned to the tax years”. Nice of them to reduce bureaucratic hassle for the smallest employers. This also happens to save the Government £450m in 2018-19, because instead of paying an increased subsidy into people’s pensions from January 2018, it will do it from April 2018.


  1. “Tuck under”.  The phrase “tucking under” is a Whitehall term of art, best illustrated with an example. We learnt yesterday that “DfID [the Department for International Development] will remain the UK’s primary channel for aid, but to respond to the changing world, more aid will be administered by other government departments, drawing on their complementary skills.” That sounds like great joined-up government. It also, conveniently, means that the Government can continue to meet its target of keeping overseas aid at 0.7% of Gross National Income, without having to increase DfID’s budget at the same rate as GNI: instead, other departments pick up the slack. Those bits of other departments’ budgets have thus been “tucked under” the ODA protection. See also: the Government is “protecting” the schools budget in real terms, while slashing around £600m from the funding it gives to local authorities to support schools, so that schools will now have to buy those services from their “protected” funding – thus “tucking” the £600m “under” the protected schools budget. (See also: in the last Parliament, the Government asked the NHS to contribute to social care funding, thus “tucking” some social care “under” the protected health budget.)


  1. Cumulative numbers. Most of the figures used in the Spending Review are “in-year” figures: when the Government says it is giving £10bn more to the NHS, it means that the NHS will get £10bn more in 2019-20 than it got in 2015-16. Then you read something like: “The Spending Review and Autumn Statement provides investment of over £1.3 billion up to 2019-20 to attract new teachers into the profession.” That’s not £1.3bn per year – it’s the cumulative figure over four years.


  1. Deploy weasel words. The government is protecting “the national base rate per student for 16-19 year olds”. Sounds great – and it will be written up in many places as “Government protects 16-19 education”. But the word “base” is doing a lot of work here. Schools and colleges that educate 16-19 year olds currently get a lot of funding on top of the “base rate” – such as extra funding for disadvantaged students. Plans for that funding have not yet been revealed.


  1. Pretend to hypothecate a tax. The Chancellor announced yesterday that – because the EU won’t allow him to reduce the ‘tampon tax’ – he’ll instead use the proceeds of that tax to pay for grants to women’s charities. This sounds great – but all he’s really saying is that, among all the many other millions of pounds of grants issued by the government to various causes, £15m will be given to some women’s charities, which might have got that funding anyway. It’s not real hypothecation: it’s not as if women’s charities will get more if there’s a spike in tampon sales. See also: announcing that local authorities can raise council tax so long as they use it to pay for social care – LAs would probably have spent just as much on social care anyway (and other services would have suffered).


  1. Shave away a small fraction of a big commitment. The Conservative party made great play in the election campaign of its commitment to provide 30 hours of free childcare to 3 and 4 year olds in working families. In the July Budget, it made more great play of re-committing to this. Yesterday, it announced that “working families” excluded any parent working less than the equivalent of 16 hours at the minimum wage, or more than £100,000. That sounds like a fairly small change – but it saves the Government £125m in 2020.


  1. Turn a grant into a loan. If government gives someone a grant, that is counted as spending and increases the public sector deficit. If instead the government gives someone a loan, that doesn’t count against the deficit, because it’s assumed that the loan will be paid back (so the loan is like an asset which the Government is holding). Recently we’ve seen a lot of government grants turning into loans – in the July Budget it was student maintenance grants; yesterday it was bursaries for trainee nurses.


  1. “Reverse” a decision that hasn’t happened yet. In 2012 the Government announced that, from April 2016, it would remove the 3% “diesel supplement” that puts a higher tax on company cars that use diesel than on others. Yesterday, it cancelled this, saving over £265m per year for the rest of the Parliament. People complain less about you cancelling a tax cut when you haven’t done the tax cut yet. (Perhaps this doesn’t qualify as a full wheeze, but there’s something wheezy about it.)


  1. “Protect” things in cash terms. If you really want to protect an area of spending, you should at least increase it in line with inflation, so that it can still buy the same amount of stuff. This government – like the Coalition before it – enjoys protecting things only in cash terms. Examples yesterday included the basic rate of funding per 16-19 year old in education, and the entire children’s services budget.


  1. Freeze things in cash terms. Yesterday the government announced that the repayment threshold on student loans – the level above which ex-students must start paying back their loans – will remain frozen in cash terms for 5 years, instead of increasing with earnings (which is what has happened to date). This saves the Government £200m in 2019-20. In a particularly bold move, the Government has even applied this rule to loans that have already been issued – changing the terms on which students took out the loans in the first place.


  1. Hide all these wheezes in sweeping statements. The first chapter of the Spending Review tells us that “£3 billion [of reduction in the deficit] is being delivered through reforms such as Making Tax Digital and further measures to tackle tax avoidance.” The innocuous phrase “reforms such as” covers the bringing forward of £900m in Capital Gains Tax (see number 1 above) and the £450m saved by delaying automatic enrolment into pensions (see number 2 above).

Catherine Colebrook is chief economist at the Institute for Public Policy Research