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We've heard from several people who are worried about the impact of small wind turbines on garden birds and other nearby wildlife. It's pretty hard to get a definitive answer on this, because most of the research so far relates to very large wind farms, which are pretty different from home turbines. 

Below is some correspondence sent to us by one of our website visitors, Paul, who has been looking into this issue.

Paul: "I've become rather fond of the individual birds that visit our garden and I would hate to accidentally kill any of them even if the overall conservation impact was small. I also wonder if it would be so small if these turbines really fall in price and they are installed all over the place. I would love to have definitive reassurance that birds see and avoid them before I buy one and start finding chopped up sparrows on the lawn!"

"I sought reassurance from the company [Windsave] that their product would not injure the birds and bats that visit our garden:"

Paul's email to Windsave:

Windsave's reply:

Windsave replied an attached a document with the following collection of quotes:

BIRDS, BATS AND WIND TURBINES

“At Black Law wind farm a close working relationship with RSPB Scotland helped enormously in achieving significant benefits for a range of species including black grouse, curlew, lapwing, snipe, otter and water vole. Black Law wind farm demonstrates that wind farms can deliver significant biodiversity gains for a range of threatened habitats and species throughout the wider countryside.” Alan Mortimer Head of Renewables Policy, Scottish Power

“Compared with past assaults, such as pesticides, loss of hedgerows, illegal persecution of birds of prey and intensive agriculture, wind farms should be low down the scale of threats. “ Mark Avery Director of Conservation, RSPB

“We are not saying we should stop building wind farms. Birds would suffer much more from climate change if we don’t.” Andy Pullin, Centre for Evidence-Based Conservation Birmingham University

There is no evidence to suggest that wind farms in the UK present a significant source of mortality to bat populations.

In addition, if we were asked to defend ourselves against past problems with bird deaths, we can say that we are aware of The Tarifa wind farm complex in Spain and Altamont Pass in California which are two commonly quoted examples where developers failed to consider the impact on large birds of prey, leading to hundreds of deaths. Similar mistakes have been made more recently at Navarra in Spain. There is no evidence that these mistakes have been repeated at UK sites, due in part to success in avoiding more sensitive sites.” Sustainable Development Commission publication, June 2005.

Birds Avoid Turbines According to Danish Research, geese and ducks learn to avoid the blades of offshore wind farms. The research was carried out by the National Environmental Research Institute in Grenavej, Denmark, using radar to monitor bird migration patterns over Nysted offshore wind farm in the Baltic Sea. The research found that the percentage of birds entering the area decreased significantly from pre-construction to initial operation, and a larger proportion of birds flew close to the wind farms at night. Overall the study found that less than 1% of the birds migrated close enough to the turbines to be at risk of collision. More at www.pubs.royalsoc.ac.uk/biologyletters.shtml

Paul's response:

Paul told them he thought this stuff was all a bit misleading and irrelevant as it relates to the impacts of big wind farms, not small home installations.

Their response:

I do apologise that you feel that we have mislead you in anyway. That was not the intention of the document I had sent you. As micro wind turbines are new to the market we can only go on the large wind turbines and what affect they have had on wildlife. We have over 50 to 60 installation test sites throughout the UK and have had no reports of any wildlife casualties at this stage. The document I had sent you was to merely inform you of how wildlife adapts to various surroundings and new additions to the landscape"

So he contacted the RSPB to ask their opinion.

RSPB response:

Dear Mr Campbell,

You are quite right that the quotes relating to offshore windfarms and other, industrial onshore windfarms bear little relevance to a domestic wind energy appliance, and indeed some of the quotes, eg: from Blacklaw, have been taken out of context, as it was the habitat improvements initiated by the developer at this site which were beneficial (although the RSPB would say that the operational windfarm itself would also have indirect positive impacts through it helping reduce CO2 production and so climate change - but that is not what the quote is alluding to).

I will discuss this with our policy team to ascertain whether any further action is needed - thank you for bringing it to our attention. In relation to domestic wind turbines generically, there really is no scientific data that we are aware of as to the interactions between these appliances and birds. However, they are small scale and this would suggest that they are less likely to be a problem in terms of bird collision. Birds tend to be very good at avoiding structures during normal flying conditions when they can see them - particularly small manoeuvrable birds like those listed in your enquiry.

Of course, it is not impossible that a bird or bat could strike the blades. However, I believe this would be likely to be a rare event. When industrial turbines have been a problem for birds in terms of collision in the past, usually it is with a large array of turbines, sited next to areas used by highly sensitive birds, or on migration routes of the same. Large raptors and wildfowl seem to be the groups most at risk of collision. Although I wouldn't want to extrapolate directly from industrial to domestic-sized appliances, as 2.5MW machines have the potential to have a much larger impact on bird populations, and usually do not, it would suggest that the small domestic appliances should have minimal impacts.

Talking to our Conservation Officer responsible for London she says: The RSPB considers the biggest risk to birds from wind turbines in London will come when turbines are located along the River Thames or its tributaries. This is because the species most likely to collide with turbines are swans, ducks, geese and waders, and large migratory birds using traditional migration routes. These routes tend to follow the rivers and streams. Individual birds could collide with a domestic turbine in Twickenham, which would be unfortunate, but would not have significant nature conservation implications. I hope that this is of some help.

Regards,

Daniel Pullan, RSPB.

Our view:

Our view at the moment is that small wind turbines pose only a very very small, if any, threat to garden birds and wildlife. According to this page at the American Wind Energy Association, a sliding glass door poses a greater threat to garden birds than a small domestic wind turbine. However we're interested in hearing of any other experiences or opinions on this issue. Just drop us an email or just add a comment below.