Short answer
Yes, birds can collide with wind turbines and die. However, research also shows that wind power is not among the major overall causes of bird mortality. Far more birds die, for example, from collisions with buildings and traffic or as a result of predation by domestic cats. This does not mean that the impact of wind power is unimportant. The risk varies significantly between locations and species, and for some sensitive species even a small number of fatalities can matter. The most important factor is therefore where wind turbines are located. Through careful environmental surveys, consideration of sensitive species and appropriate mitigation measures, the risks can be significantly reduced.
Why is this discussed?
Wind turbines are large structures that birds sometimes collide with. The issue attracts attention because people care about nature, and because individual cases in which, for example, eagles are killed can receive considerable attention. At the same time, the issue has become part of the broader debate about the energy transition. Social media and opinion pieces sometimes claim that wind power poses a major threat to birdlife in general. That picture is not supported by the research. Wind power does cause bird fatalities, but other human-related factors are responsible for far greater bird mortality overall.
It is also important to distinguish between total bird mortality and the impact on a particular species. Wind power can pose a significant risk in the wrong location, especially for certain sensitive species. The issue therefore largely comes down to which species are present and how the wind farm is sited and designed.
Common misconceptions
“Wind power is a major threat to bird populations in general”
Research does not support that description. Compared with several other human-related risks, wind power contributes relatively little to overall bird mortality. That does not mean that every wind power project has a limited impact. Risks can be considerably greater in sensitive locations and for certain species, particularly birds of prey. The purpose of environmental surveys, permitting processes and mitigation measures is therefore to identify these risks and reduce them as far as possible.
“Wind power is the biggest cause of eagle deaths”
There is no evidence to support describing wind power as the biggest overall cause of bird mortality, but eagles are among the birds that can be particularly vulnerable to wind turbines. Soaring birds of prey, such as eagles, buzzards and kites, can face a higher collision risk than many other groups of birds. This is why eagle territories and nesting sites receive particular attention when new projects are planned. In Sweden, buffer zones around known nesting sites of white-tailed eagles and golden eagles are among the measures used to reduce risks. The distinction is important: the fact that wind power accounts for a relatively limited share of overall bird mortality does not mean that the risks can be disregarded for a particular species or at a particular location.
What do the facts say?
Birds can collide with wind turbines, but the risks vary
It is well documented that birds sometimes collide with turbine blades or towers. The level of risk varies between species and locations. Birds of prey such as eagles, kites and some species of buzzard can be more vulnerable than many other groups of birds.
When researchers assess the impact, the question is therefore not only how many birds die, but also which species are affected. For species that are rare, long-lived or produce relatively few offspring, a small number of fatalities can have a greater impact on the population than the same number of deaths among very common species.
Wind power is a relatively small source of bird mortality
Research shows that wind power causes bird fatalities, but also that other human-related factors account for far more bird deaths overall. These include domestic cats, traffic and collisions with windows and other structures. Swedish research into wind power in forest environments has also found low overall bird mortality in the areas studied, although the results varied between locations. This does not make the birds that are killed by wind turbines any less important. But it helps put the impact of wind power into perspective alongside the other risks birds face.
Siting and mitigation measures are crucial
The most effective way to reduce the negative impact of wind power on birds is to avoid locations where the risks are high. These may include areas with high concentrations of birds or places used for breeding, wintering or resting during migration. Through environmental surveys and knowledge about how different species use the landscape, many risks can therefore be identified during the planning phase. Buffer zones and adjustments to the positioning of individual turbines can then be used to further reduce the impact.
What affects the assessment?
- Species: Some species are more vulnerable than others.
- Location: Breeding areas, migration routes and areas with high conservation value require particular consideration.
- Number of birds: Areas with large concentrations of birds can present greater risks.
- Landscape: Topography, coastal environments and other local conditions can influence the risks.
- Project design: The positioning of individual turbines and the overall design of the wind farm matter. This is why birds are an important consideration in the environmental assessment of a wind farm.
- Mitigation measures: Surveys, buffer zones and other adaptations can reduce the impact.
- Population size: The same number of collisions can have very different consequences depending on how common or rare a species is.
Conclusion
Wind turbines kill birds, but it is misleading to describe wind power as one of the greatest overall threats to birds. Research shows that other human-related factors account for far greater bird mortality overall. At the same time, wind power can pose a significant risk locally and for certain sensitive species. Looking only at the overall statistics is therefore not enough. Wind power in the wrong location can still be a problem for birdlife. The key issue is therefore where and how wind power is developed. Environmental surveys, careful siting, buffer zones and monitoring can help avoid many of the greatest risks. The most accurate conclusion is not that wind power is risk-free for birds, but that its overall impact is limited compared with several other threats, and that much of the risk can be reduced through appropriate siting and careful consideration of birdlife.