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Wind Farms: Their True Impact on Birds and Bats

Wind Farms: Their True Impact on Birds and Bats

By Emma Bennett

Monitoring wind farms for impacts on birds and bats is an expense that could be better directed at conservation programs for threatened species.

Almost 1000 extra wind turbines are approved for construction in Victoria over the next 10 years. The wind power industry has faced many challenges, one of which is to monitor, reduce and mitigate the impacts of turbines on bird and bat populations.

Research in the USA and Canada has concluded that wind farms are likely to account for less than 0.1% of anthropogenic causes of bird deaths. This makes sense given the volume of evidence that cats are the biggest impact on our wildlife, with estimates that around one million birds are killed daily in Australia by feral and domestic cats. Estimates from overseas suggest that cats account for around 75% of all bird deaths, followed by collisions with buildings, cars and power lines. Factors such as pollution, climate change and agrochemicals are also considered direct causes of bird mortality, with figures much higher than those derived from wind farm impact estimates.

To understand why wind farm operators care about their impact to wildlife, we must consider that wind energy is promoted as a clean, green energy solution. Therefore the industry is held to higher environmental standards than other sectors of the energy market, such as coal power stations and transmission lines. In addition, some of the first wind farms built in the USA were poorly sited along major migratory bird flight paths. High impacts to birds, including the American bald eagle, were recorded, and this led to changes in the positioning of turbines in the landscape.

Within each state in Australia, different conditions are placed on wind farm operators to ensure that impacts to bird and bats are minimised and evaluated. In Victoria this requires many years of investigation and site studies. The position of each turbine within the landscape is determined, not by the best wind resource but often by where the lowest impacts to birds and bats are likely to occur within the area of the wind farm. Scientists and consultants spend many hours in each season at the proposed turbine sites recording how high birds are flying, where they are flying to and from, which species are using the site and which species are likely to fly within the circular area of the turbine blades. Only birds or bats that fly within this risk zone have the potential for collision.

Direct observation data are then used to develop models of bird flight paths, and estimates of likely impacts are derived. Planning approval is subject to the number and species of birds and bats that have the potential for impact. Once approved under state planning laws, wind farm operators must then demonstrate that the predictive impact models are a good estimate of the actual impact. This is where I come in – with the help of detector dogs.

My role has been to evaluate these impacts and report to both industry and the government what those impacts actually are. We do this by surveying the area under the turbine for evidence of birds and bats that may have collided with the turbine. We undertake searches using trained detection dogs at least twice per month for several years. The use of dogs provides a reliable, unbiased survey tool that has a much greater chance of finding small birds and bats then other available survey tools.

We also estimate how many carcasses are taken by scavenging animals before we have a chance to find them by placing carcasses in the field and recording how long they remain there. By combining the number of birds detected and accounting for scavenging and the detection accuracy of the dogs, we are able to develop good estimates of the number of birds and bats affected at each wind farm site.

For the past 15 years I have surveyed around half of all the turbines installed in Victoria, and provided robust estimates to government and wind farm operators about the impact to birds and bats. While collecting this monitoring data has been essential to understanding the patterns of impact and the susceptibility of Australian species to wind farm collision, we are now at the stage of monitoring for the sake of monitoring. I estimate that wind farm operators have spent tens of millions of dollars monitoring this impact. With an additional 1000 turbines due to be installed in Victoria over the next 10 years, that figure will rise to hundreds of millions.

Those of us working within the industry know the impact here is similar to what has been observed overseas. We know which species are most susceptible, we recognise that most wind farms have had a negligible impact to local bird and bat populations, and that no species has been put at risk of population impacts at an individual wind farm in Australia. Yet the current plan is to continue to spend hundreds of millions of dollars monitoring individual sites over the next decade.

But what if we did something different? What if we assumed that wind farms had an impact to species populations and used some of that money to reduce other threats, such as habitat loss and predation by cats and foxes?

As an independent scientist with a passion for conservation, I want to see some of this funding redirected into projects that increase the survival of our threatened species rather than simply monitoring a negligible impact. Through the establishment of an industry-supported research fund, we aim to collaborate with the Victorian government to change existing planning laws, remove the onus of individual wind farms to monitor their own impacts and instead look at the cumulative impacts of wind farm development on birds and bats at a state level. By providing a collaborative approach with industry, government and research institutions, we will ensure that a proportion of the funding goes to direct action to improve the survival of threatened and significant species. We can do this by restoring wetlands and critical habitat, through fox and cat control programs, and by reducing key threatening processes that are having a negative impact on population survival.

Monitoring is still an important component of any ecological action, and a proportion of the funds will continue to investigate direct and indirect impacts to birds and bats at wind farms as well as monitor populations where direct action is occurring to see if we can improve the outcomes for not only our threatened and endangered species, but for all wildlife. The establishment of a coordinated industry-funded research/direct action group has been announced in the USA, and is an inevitable step if we are committed to achieving the best outcomes for wildlife. Primarily funded by industry, the institute, with the support of government and the not-for-profit sector, would step up the standards for best practice, provide a coordinated research group to increase knowledge and understanding, and deliver net improvements for our threatened species.


Emma Bennett is a PhD candidate at Monash University’s School of Biological Sciences.