Course:CONS200/2023/The impact of wind turbines on birds and potential mitigation strategies

Introduction

Wind energy has become an increasingly important source of renewable power in recent years, playing a crucial role in the global transition towards cleaner and more sustainable energy production. As the number of wind turbines and wind farms has grown, concerns have emerged regarding the potential impacts of these installations on bird populations. While wind energy offers significant benefits in terms of reducing greenhouse gas emissions and dependence on fossil fuels, it is essential to understand and address any adverse effects on avian species to ensure sustainable and ecologically responsible development.

The relationship between wind turbines and birds is multifaceted, with several areas of concern arising from the interaction between these structures and bird populations. These concerns include the risk of direct collisions between birds and turbine blades, habitat fragmentation due to the construction and operation of wind farms, disturbance of breeding and nesting behaviors, and the creation of barriers to movement that can disrupt migratory routes. The consequences of these impacts can range from localized declines in bird populations to broader implications for biodiversity and ecosystem health.

As the wind energy sector continues to expand, the importance of understanding and mitigating the potential impacts on birds becomes increasingly pressing. Researchers, conservationists, and the wind industry have been working together to identify and implement strategies to minimize harm to bird populations. Such strategies include careful site selection to avoid critical habitats, the use of technology to detect and deter birds from approaching turbines, and ongoing monitoring and research to improve understanding of the complex interactions between birds and wind energy infrastructure.

Impacts on Bird Species

Wind turbines can influence birds in a number of ways, affecting the birds directly from collision or indirectly from disrupting habitats and migration patterns.

Collision

Wind turbines can sometimes be an obstacle to birds' migration routes.

Birds can collide with the rotating blades of wind turbines, leading to injury or death. This is more likely during migration when birds travel long distances and may be unfamiliar with the turbine locations. Birds rely on thermal and orographic updrafts for efficient long-distance flights, but wind turbines can disrupt these air patterns, posing a potential hazard. Additionally, some birds have better lateral than frontal views, which could increase the likelihood of collisions with turbine blades.

Collision risk for birds is influenced by various factors such as bird species, population, behavior, weather conditions, topography, and wind farm characteristics, including lighting. The risk is often greater in areas with high bird activity or along migratory routes and local flight paths, especially when intersected by turbines. Birds may suffer direct mortality or lethal injuries from collisions not only with rotors but also with towers, nacelles, and other associated structures like guy cables, power lines, and meteorological masts.

One study estimated that approximately 234,000 birds die annually in the contiguous United States as a result of collisions with wind turbines. Raptors and other large birds may face higher risks, as their flight patterns often occur at similar heights as rotating turbine blades. The impact of wind turbine collisions can also vary seasonally, with increased risks observed during migration periods when large numbers of birds traverse areas containing wind energy installations.

Habitat fragmentation

Wind turbines can degrade land habitats

Wind turbines and their associated infrastructure can lead to bird habitat fragmentation, which is the division of continuous habitats into smaller, disconnected patches. This fragmentation can negatively affect bird populations by disrupting foraging, breeding, and nesting behaviors, as well as reducing overall habitat availability. Fragmented habitats can also result in the isolation of bird populations and increased susceptibility to predators, ultimately affecting the genetic diversity of the population.

A study discovered that wind turbines and related access roads can reduce breeding bird densities, particularly for ground-nesting species like the Eurasian golden plover. The Eurasian golden plover (Pluvialis apricaria) is a migratory wader species that breeds in open landscapes, such as moorlands and tundra. The construction of wind turbines and access roads can lead to habitat loss and degradation, directly affecting the availability of suitable nesting sites for these birds.

Additionally, habitat fragmentation can indirectly affect bird populations by altering predator-prey relationships, increasing predation pressure on certain bird species. One research indicated that wind turbine construction can increase the number of common ravens, which are known as "nest predators", potentially exacerbating the negative impacts of habitat fragmentation on bird populations.

Physical barriers to movement

Wind turbines can disrupt bird migration routes by acting as physical barriers to movement and posing a collision risk. Migrating birds rely on specific flight paths and stopover sites to complete their long journeys, and the presence of wind turbines along these routes can interfere with their navigation and force them to alter their routes or expend additional energy to avoid the structures.

A study found that common terns (Sterna hirundo) altered their flight paths to avoid a wind farm in the North Sea. The study observed that the terns increased their altitude and changed their routes when encountering the wind turbines, indicating that wind farms could act as barriers to movement for some bird species.

The impact of wind turbines on bird migration can vary depending on the species and the specific location of the wind farm. A comprehensive review on the potential impacts of wind farms on bird migration found that while some species may show little reaction to the presence of wind turbines, others, such as geese and swans, might exhibit stronger avoidance behavior. The review also noted that the cumulative impacts of multiple wind farms along migratory routes could be more significant than the impact of individual wind farms.

Disruption of migration routes can have consequences for the energy expenditure and survival of migrating birds. If birds are forced to deviate from their optimal flight paths or to fly at higher altitudes to avoid wind turbines, they may consume more energy, which could negatively affect their ability to complete their migration and reproduce successfully.

Disruption of breeding and migration patterns

Wind turbines can have a significant impact on bird breeding patterns following habitat loss and fragmentation. The construction and operation of wind energy infrastructure can lead to alterations in bird behavior, affecting critical breeding processes such as mate selection, nest construction, and parental care.

A study found that the presence of wind turbines can result in the displacement of breeding birds, particularly grassland birds, due to habitat loss and disturbance. The study highlighted that the displacement of breeding birds was more severe within 150-250 meters of the wind turbines. Consequently, the overall reproductive success of affected bird species can decline with the presence of wind farms.

The noise generated by wind turbines can also disrupt bird breeding patterns. A study shows that breeding bird density decreased with increasing turbine noise levels, affecting species such as the Savannah sparrow and the bobolink. This demonstrates the negative impact of noise and how it can lead to birds avoiding suitable habitats close to wind turbines, which may further impact their breeding success.

Past and Current Remedial Actions

windmill vs wind turbine design

Over the course of history, humanity has engineered and developed many different ways to harvest energy in order to power our technological needs in our lives, from consumable energy sources like fossil fuels, to more renewable energy sources like wind turbines and wind farms. Though this change from consumable energy to renewable energy does provide a safer and cleaner option, it still impacts the natural environment and behaviors of wildlife across the globe, such as wind turbines impacting bird habitats, and migration routes and patterns. In the 1980s, there was the mass advancement in terms of research of many different sciences that are used in today's wind turbines, like aerodynamics. The sciences of aerodynamics, atmospheric wind flow, mechanical system, civil engineering and others, were used to understand wind patterns, and as time progresses, there are developments in the materials used to create wind turbines, from old heavy metals, to now more lighter and more durable materials that are also more cost efficient.

Accommodation of blade size

The sizes of wind turbines have drastically increased over the course of 20 years since the 1980s, and still continue to do so in modern times. This is to accommodate the larger diameter of the rotors to increase the Kilowatt capacity that these turbines are capable of. This also allowed the idea of a low-cost, large-scale trend with wind turbines, where there is less conservative manufacturing, and more optimization in wind-generated energy. With the size increase of the production of more modern wind turbines, more computing power was required, to allow more sophisticated design calculations in manufacturing and designing in a more straightforward manner. However, with the increase in size to wind turbines, many issues in regards to birds and other wildlife have risen, and proved dangerous to the conservation efforts to protect and monitor birds and their habits.

Past problems

Proves dangerous to local birds and bats who can die from potentially running into the blades or structure of the wind turbine, along with causing noise pollution and reduction in survival and reproduction. A major problem that has occurred is the fact that a lot of research among wind farms that this topic is done around a lot of gray literature, mostly of unpublished reports and data, giving concerns as to how much of the data we have on wind farms we can truly trust, and how much still needs to be research, despite the developments made since the 1980s.

Past remedial actions

While there are many efforts in creating ever improving wind turbines in different regions to farm wind energy, there are countless actions being taken in order to protect these turbines from the harsh elements of nature. There have been discussions of the use of support structures to help sustain the load that the wind turbines are capable of handling in extreme weathers. Though these support structures allow tidal wind turbines to last longer, it does take up more space along with the wind farms, and even making attachment points on the seabed, which not only creates problems for land animals that use the local areas like birds, but even some marine animals.

Current problems

large wind turbine in bird flight path

More wind farms and power plants are being built in shrub- and woodland to farm energy in more recent times, compared to the past where it was done in more open landscapes and because of this, while there is more information is recognition on wildlife impact wind farms have in open landscapes, there is significantly less in shrub- and woodlands. More modern designs of wind turbines, which are taller, and have larger blade lengths with slower tip speeds pose a higher danger to collision upon birds than earlier models of wind turbines.

Current remedial actions

There are different mitigation strategies that are currently under discussion that are labeled in two different categories: best-practice measures and additional measures. Best-practice measures are those that can be adopted by any wind farm development and should be integrated as a standard for the industry, whereas additional measures are aimed to be specific measures that target particular developments. Some examples of measures that fall into one of these two categories are the avoidance of key conservation and protected areas, increasing the visibility of rotor blades to wildlife, and implementing habitat enhancements for species using the site. There have also been efforts in monitoring bird behaviors around wind farms using remote sensing technologies like radars, thermal animal detection systems, and population modeling to measure potential and actual collision mortality of birds. While the use of monitoring technology is still relatively new, and will definitely need improvements, there is a great amount of potential with them and can help with the conservation of birds and their migration patterns in the long run.

Options for Potential Management Strategies

Various factors influence the impact of wind turbines on birds, and mitigation solutions may involve a combination of different strategies and consideration of specific circumstances for wind turbines and target bird species in different locations. As a reference, this article will offer several straightforward strategies to help mitigate the impact of wind turbines on birds.

Bird monitoring

To minimize the impact of wind farms on birds, implementing bird monitoring strategies is crucial. One such strategy is setting up monitoring points near turbines equipped with advanced radar systems and cameras. Another approach is to use a sensor array that has different types of sensors like vibration, optical, and bioacoustic sensors with event-triggered structures. These sensors record data, and by visually inspecting and analyzing the recorded vibration signals, nearly half of the impact events can be successfully identified. This enables real-time monitoring of bird movements, and if large-scale movements are detected, turbines can be immediately shut down to prevent collisions. Additionally, wind turbines only need to stop briefly during the day to protect birds. At night, when bird activity is low, turbines can operate normally, reducing any negative impact on energy production. It's important to strike a balance between renewable energy and environmental conservation.

Alter the configuration of turbines

Wind turbine shape

The height of a wind turbine plays a crucial role in determining its impact on avian species. Research indicates that as the height of a turbine increases, the adverse effects on bird populations decrease. Conversely, the length of turbine blades is directly proportional to the negative impact on avian species. To mitigate this issue, it is recommended to construct slender turbines that are taller in height but smaller in size.

wind turbine

Wind turbine colour

Changing the colour of wind turbine blades and towers is another effective way to minimize their impact on bird populations . By adjusting the colour contrast of each blade and the area it covers, it's possible to make it easier for birds to detect and avoid turbines during their flight. This approach can help reduce the risk of collisions and other negative impacts on avian species. This method of reducing colour contrast is simple and doesn't interfere with shipping or aviation interests.  As there are a wide variety of bird species,  it's essential to note that the effectiveness may vary for birds that don't rely on forward visual information.

Site selection

The siting of wind turbines is a complex issue, particularly in terms of its impact on bird populations. The placement of wind turbines in areas with high bird activity or in important bird habitats and migration routes can have significant negative consequences for avian species. Therefore, careful consideration should be given to selecting suitable sites for wind turbines, considering the impact on bird conservation interests.

Bird sensitivity map

Composite map of Scotland showing wind farm sensitivity ratings for bird species of conservation concern.

One effective approach is to create a bird sensitivity map, which can help identify areas that are suitable for wind turbine siting while minimizing the impact on bird populations. This map takes into account various factors, such as foraging range, collision risk, and sensitivity to disturbance, to assess the suitability of potential sites. By analyzing data from bird surveys and monitoring programs, it is possible to identify areas with low bird activity and those located far from important bird habitats and migration routes.

The creation of bird sensitivity maps is a crucial step in responsible and sustainable wind energy development. It is a collaborative effort that involves multiple stakeholders, including wind energy developers, bird conservation organizations, and local communities. The map can be used to inform the siting and design of future wind energy projects, helping to minimize the impact on bird populations and ensure the long-term viability of avian species. Extensive and long-term bird distribution data surveys are required in the production process, and significant funding is needed, but currently, most species do not have sufficient data for assessment.

It is important to note that these strategies may not completely eliminate the impact of wind turbines on birds, but they can help reduce it. Stakeholders should work with local regulatory or governmental agencies to develop specific strategies based on the actual situation to ensure effective implementation of the strategies and ensure the safety of birds.

Conclusion

Wind turbines, while a valuable source of renewable energy, have raised concerns regarding their impact on bird species. Collisions with turbine blades and other structures can lead to fatalities, with certain species and migratory periods posing a higher risk. Habitat fragmentation caused by wind farms can disrupt breeding patterns, particularly for ground-nesting birds, while the presence of turbines can disturb birds in the vicinity and force them to abandon essential habitats. Additionally, wind turbines can act as barriers to movement, potentially affecting bird migration routes and causing birds to change their flight paths, which may increase energy expenditure and impact their survival and reproductive success.

To mitigate these impacts, past and current remedial actions have focused on improving wind farm siting and design, implementing wildlife-friendly operational strategies, and investing in research to better understand the complex relationship between birds and wind turbines. Future remedial actions may involve the development of advanced technologies to minimize bird collisions, the implementation of adaptive management strategies based on ongoing monitoring of bird populations, and closer collaboration between the wind energy sector and conservation organizations. In conclusion, while the impact of wind turbines on birds is a pressing concern, a combination of thoughtful planning, research, and innovative solutions can help balance the need for clean energy with the protection of avian species and their habitats.