Bats, birds and blades: wind turbines and biodiversity 

All the conventional ‘green’ scenarios for reducing carbon emissions include a dramatic upscaling in renewable power generated by wind, both on and offshore. However, the environmental impacts of this large-scale industrial deployment – both of turbines and power lines, frequently in relatively natural areas – are often neglected by climate campaigners. Here two ‘planetary boundaries’ conflict: those of biodiversity and climate change.

That some wind farms kill worrying numbers of birds, especially large birds like raptors, is undeniable – yet the wind industry does its best to downplay the impacts. As the American Wind Energy Association puts it:

Wind power is far less harmful to birds than the fossil fuels it displaces. Incidental losses of individual birds at turbine sites will always be an extremely small fraction of bird deaths caused by human activities.

Both these statements may be technically true, but they do not mean that additional bird kills by increasing areas of wind farms are not a concern – they mean that new turbines are yet another human pressure on bird species which are already a matter for serious conservation concern. This is particularly the case as more power lines will be needed to connect disparate wind farms in upland or remote areas: in this sense the decentralised energy generation so beloved of greens is worse for conservation then centralised generation in big power plants, whose transmission infrastructure by and large already exists.

Here is an interview with the Norwegian ornithologist Alv Ottar Folkestad, who is concerned with the survival of white-tailed eagles in coastal areas of Norway:

… what to me is a really scaring prospective [sic] is the way wind power development has been introduced in this country. The first wind power plant of significant size in Norway, on Smøla, is localized into the most spectacular performance of nesting concentration of White-tailed Eagles ever known. There are plans for making wind power into huge dimensions, and most of them localized in the most pristine coastal landscape of the most important areas of the White-tailed Eagle. During the last five and a half years, the wind power plant on Smøla has been killing 40 white-tailed eagles, 27 of them adult or sub adult birds, and 11 of them during 2010. There are no mitigating measures taken so far, and hardly any to think of, and there is no indication of adaptation among the eagles to such constructions.

Similar stories are coming from Spain, where large-scale onshore wind development in recent years has reportedly hit some raptor populations hard.

'Jorge', the last great bustard in Cadiz region, killed by turbines or power lines

In Greece, this extraordinary video shows an actual collision when a griffon vulture is hit by a spinning turbine blade.

Perhaps the best-studied wind farm in the world is at California’s Altamont Pass, where dozens of protected species from golden eagles to burrowing owls are killed each year, making the area a significant population sink for these birds. Expert Shawn Smallwood has conducted surveys in the area, and estimates that 70-80 golden eagles are killed each year by turbine blades, out of a total Californian population of 3000-5000 eagles. As he explains on this video:

We usually found the bird carcasses nearby the turbines. Usually they were found dismembered. A lot of times the head was knocked off, or a wing, or the bird was cut in half length-wise, or across the middle.

Remediation measures are now underway, removing those turbines located in areas most frequented by raptors. But how compatible is wind energy with bird conservation on a wider scale? I put that question to Clive Hambler, a conservation biologist at Oxford University’s Department of Zoology. This is his answer in full:

I think wind farms are potentially the biggest disaster for birds of prey since the days of persecution by gamekeepers, and I think wind farms are one of the biggest threats to European and North American bats since large scale deforestation. The impacts are already becoming serious for white-tailed eagles in Europe, as is abundantly clear in Norway. A wind farm – built despite opposition from ornithologists – has decimated an important population, killing 40 white-tailed eagles in about 5 years and 11 of them in 2010. The last great bustard in the Spanish province of Cadiz was killed by a wind development. In my experience, some “greens” are in complete denial of these impacts, or hopefully imagine that these bats and birds can take big losses: they can’t because they breed very slowly.

Birds of prey often soar where wind farms are best-sited, and may be attracted to their deaths by the vegetation and prey around the turbines. A similar deadly ecological trap has been proposed for bats, with some species attracted by insect prey or noise around the turbines.

There are very serious suggestions of a cover-up of the scale of the problem, by some operatives hiding the corpses of birds, but you only have to look at the Save the Eagles website to see the evidence accumulating despite scavengers or deception.

To my mind one of the worst problems is that wind farms will prevent the recovery of birds of prey, other threatened birds, and bats – denying them great swathes of the European and North American continent where they once dwelt. This flies in the face of the legally binding Convention on Biological Diversity, which encourages restoration of habitat and species whenever practicable. It makes a nonsense of the idea that wind is ‘sustainable’ energy – except in that it sustains and renews ecological damage.

Strong stuff. And as Hambler – who is equally critical of proposals for tidal barrages to harvest marine energy at the expense of mudflats, fish and seabirds – says, bats are just as much under threat as raptors. Earlier this year researchers writing in Science journal (sub req’d) suggested that large-scale wind development in the US Mid-Atlantic Highlands could join ‘white nose syndrome’ as a major killer of bats, potentially helping spur their extinction from wide areas of the country.

So where does all this leave us? The RSPB in the UK has been trying to carve out a sensible position amongst the conflicting objectives of supporting renewable energy whilst also protecting birds. It states:

… the RSPB supports a significant growth in offshore and onshore wind power generation in the UK.

We believe that this growth can be achieved in harmony with, rather than at the expense of, the natural environment. We will therefore continue to require that wind farms are sited, designed and managed so that there are no significant adverse impacts on important bird populations or their habitats.

Increasingly this does mean opposing windfarms sited in inappropriate areas, and encouraging developers to take note of which regions should be out of bounds entirely. As always there will be conflicts between the objectives of reducing emissions, protecting nature, and mitigating human impact on the land. Those whose enthusiasm for wind seems to know no bounds should duly take note.