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Whatsapp A wind farm in sunset with birds nearby.

Dr Cindy Hull is an avian ecologist who investigates claims that wind farms kill birds and bats in large numbers. Dr Hull writes that misinformation has muddied the waters on this issue, adding that her research debunks a number of common myths.

I have been involved in the investigation of the effect of wind farms on birds and bats for about 13 years at both Hydro Tasmania and Roaring 40s Renewable Energy. I work in this area due to my interest in birds, but also because I worry about our planet. I want to play my part (as small as it is) to reduce the catastrophic impacts of climate change and to protect species.

I have always had a fascination with wildlife, and I want to do my part to assist in its protection. I also love scientific research, in particular the testing of an idea, the challenge of designing a really good study, and perhaps most of all, the analysis of the data once it’s collected.

It’s exciting when you analyse data and see patterns emerge, particularly if they are unexpected. It is particularly surprising when an expected effect is not supported by the evidence, which challenges our assumptions and paradigms. But that’s science—it is designed to be objective.

We have done a lot of work studying how eagles respond to the presence of turbines. The key finding was that eagles demonstrated an awareness of the turbines, and usually actively avoided them.

A good study aims to tease out real patterns from the 'noise', and to make sure that results are not affected by our biases, expectations or other factors. We seek to identify the meaningful trends, the real effects, and let the data speak for itself.

I believe that the best way we can protect our wildlife is to conduct robust scientific research to understand the ecology of a species, the impacts it might be suffering and to investigate if there is anything we can do to minimise the impacts.

We have been investigating the effect on birds and bats of the Bluff Point and Studland Bay Wind Farms in north-west Tasmania. We have conducted many studies, from monitoring required as part of our State and Commonwealth permits, to targeted studies that we have initiated to try to understand a specific issue, or where possible, to reduce an impact that has been documented.

We have learnt a lot in the last ten years at these wind farms.

Not all species of bird are at equal risk of collision with turbines. We’ve found that only about 20 per cent of the species present at these wind farms are involved in collisions with turbines. The vast majority of collisions involve birds colliding with moving turbine blades, and those at risk are the ones that spend time in the region that the blades move (which is called the rotor swept area).

Modern turbines have a rotor swept area of between 65-115m, meaning the blades sweep through the zone from about 35-125m above the ground, so any birds that don’t fly in this zone are very unlikely to collide (such as those that are only present in trees or shrubs).

Bird collisions with turbines are statistically rare events. What we need to know is whether the number of collisions that do occur could be having a negative impact on the conservation status of a species—that is, will it be pushed closer to extinction?

Similar to birds, there are specific features that make some bat species more at risk of collision. The primary factor again is whether the bat is present in the rotor swept area of turbines.

We have done a lot of work studying how eagles respond to the presence of turbines. A three-year observational study we conducted at these wind farms found that eagles adjust their movements through the wind farm once turbines are installed. They also alter their behaviour in response to whether the turbines were active or not, and under different weather conditions.

The key finding was that eagles demonstrated an awareness of the turbines, and usually actively avoided them.

One of our key areas of current research is determining what are the factors involved in collision risk. Only by understanding these factors can we hope to develop strategies to reduce the risk.

There is a lot of research into the effect of wind turbines on birds and bats around the world. Until relatively recently, much of this research wasn’t published in the peer-reviewed literature. That’s not to say that the research hasn’t been thorough and appropriate, it just means that it hasn’t passed a formal peer-review process, which provides a layer of credibility. Also, sometimes this material is difficult to access, unlike that in scientific journals.

Part of my job is to keep abreast of all this research. It can be daunting, as there is a lot being done around the world. There are now some excellent scientific conferences held each year on the topic of birds and bats and wind farms, and this sharing of knowledge and findings is critical to the scientific process.

It’s interesting that while some of the issues found at wind farms are the same around the world, some are not. It’s important to remember that assuming what someone found at one site will automatically be found at another doesn’t constitute good science; assumptions need to be tested or strategies trialled.

The death toll of birds due to wind farms Listen to Ockham's Razor to hear Dr Cindy Hull on what's being done to assess the scale bird deaths from wind turbines. [Photo: Chuck Coker; Flickr.com/CC]

While a lot has been learnt about wind farm effects, there is more to be learnt.

Unfortunately in the area of wind farms there is a lot of misinformation and myths, even when scientific evidence exists. Inaccurate information or myths do not progress understanding or, in fact, save species. In my view it only muddies the water, distracts focus and wastes time.

One of the myths that I regularly encounter is that it is predominantly raptors that are at risk of collision with turbines.

Yes, there are some wind farms that have demonstrated impacts to raptors, but there are a number that don’t. Further, what we found at our sites is that not all raptors are equally affected. Raptors are one of the groups of birds that are often the focus of the community—but that might be more about human perceptions and emotions than what the evidence shows.

We need to be careful that focusing on one group doesn’t result in us being blinded to impacts on other groups. Instead, we need to objectively view the results of robust scientific studies to see if species or populations are being significantly impacted.

Wind farms are one of the few sources of impacts to birds and bats that are being systematically monitored. Most other forms of energy generation do not monitor impacts. Nor do we have widespread systematic monitoring of all the other human-related activities that we inflict on species—such as collisions with cars, powerlines, windows, poisoning, shooting, pollution, etc.

No data does not mean no impacts, it means no data.

Although it varies across jurisdictions, State and Commonwealth regulators often require that the wind industry intensely monitor its impacts.

We support and endorse these monitoring and reporting requirements, but it has led to the incorrect perception that this is the only industry that has impacts. I think it’s our duty to determine the range of impacts on birds from all sources, determine which are the most significant and try to reduce them. Finally, it is important that the facts—derived from robust scientific studies—are communicated and that we’re not simply perpetuating myths and misinformation. It’s the least we can do.

Dr Cindy Hull works for Hydro Tasmania and studies the way birds and wind farms interact. This is an edited transcript of her Ockham's Razor broadcast.

