Does offshore wind actually kill birds?

The question of whether offshore wind turbines harm birds has gotten a lot of attention recently. You may have heard that birds die when they fly into the wind turbines off our coasts. So why do wildlife conservation organizations, such as Audubon and the National Wildlife Federation, support responsible development of offshore wind? 

It’s primarily because, while wind turbines do harm some birds, the threats pale in comparison to other threats that birds face, including those from fossil fuels and climate change that offshore wind actively helps to reduce. And, even better, there are many ways to minimize the impacts. Let’s break it down:

Do birds collide with offshore wind turbines?

A single blade of an offshore wind turbine can be more than 350 feet long, roughly equivalent to the length of a football field. This creates a large “swept zone,” the area covered by the turbine’s spinning blades. The swept zone and turbine tower can both become obstacles for nearby birds, posing collision risks.

Most songbirds, puffins and many other bird species, don’t spend much time at the height of a wind turbine’s swept zone. Other species, such as pelicans and seagulls that tend to spend more time at higher altitudes, are at higher risk.

There are currently no reliable estimates of how many birds have been killed in collisions with offshore wind turbines. Studies drawing on data from 2012 – before the first U.S. offshore wind project – estimated that wind turbines kill anywhere from 140,000 to nearly 700,000 birds annually in America. This figure is likely higher nowadays, considering we’ve added roughly 3,000 turbines each year since.

But being hit by wind turbine blades is far from the biggest threat that birds face. One study estimated that house cats in the U.S. kill more than 1.4 billion birds every year. Another study estimates that more than one billion birds are killed annually in the U.S. as a result of colliding into buildings. These threats harm hundreds, if not thousands of times, more birds each year than offshore wind.

How to prevent birds from colliding with offshore wind

While the problem of bird collisions is often overstated, there are still ways to minimize offshore wind’s impact. In the planning phase, developers can use information about the prevalence of birds and their flight patterns to avoid installing offshore wind turbines in high-risk areas.

When built, adding automated lights and improving the visibility of blades – such as by painting one blade black or using pattern designs – can help birds spot and avoid the swept zone. 

Once in operation, tracking and monitoring bird populations can also help ensure offshore wind turbines are not posing an outsized risk. Tracking bird movements can also help enable other strategies such as slowing or stopping the wind turbine’s blades when lots of birds are in the area.

There’s also a big need for more research. The first US-based offshore wind project began operating in 2016. Continued monitoring of offshore wind’s impacts can help reduce its impact and move us towards an energy system that minimizes its impact on birds and the rest of the ecosystem. 

Other impacts of offshore wind on birds

Collisions are not the only way that offshore wind can impact birds. Turbines can create barriers to bird movement, making it more difficult to reach specific habitats and thus altering bird behavior. Also, wind turbines have been shown to affect ocean ecosystems – from altering currents to impacting plant life – which can impact sources of food for birds. 

Arguably the most important impact of offshore wind on birds is actually a benefit: reducing reliance on fossil fuels. Climate change, which is accelerated by fossil fuel combustion, poses significant threats for a large portion of bird species. Moreover, habitat disruption from oil and gas production, and the risks of oil spills, pose their own set of problems that threaten birds and their ecosystems. Offshore wind proliferation can help shift us away from polluting sources like coal and natural gas, providing us with clean energy instead. 

Moving forward with offshore wind

Offshore wind turbines will have effects for marine life and birds alike. It is essential that we accurately evaluate the extent to which offshore wind impacts birds – and mitigate impact through careful planning and smart design. We need more clean energy, and for the 29 states with offshore wind potential, the strong steady power of the winds off our shores are a massive and underutilized energy resource that doesn’t pollute and never runs out.