Office of Law Enforcement
Pacific Region/Pacific Southwest Region


September 2009

Wind vs. Wings: Can we have both?

This fall when you’re on the road, taking a trip to go camping, watching a friend get married or dropping your kids off at college, you may get the chance to see a wind power farm.  When you view those large and powerful structures in the distance, a natural reaction is for you to be impressed and proud that we are using renewable energy.  But the next time you spot a wind power farm, take a moment to observe whether birds are near it.  Would it alarm you if you saw a bird was flying close to a spinning wind turbine?

Line of Wind Turbines
Photo by Cindy Gray, U.S. Fish and Wildlife Service

If you’re alarmed, then you have good instincts.  In fact, hundreds of birds and bats are killed each year by flying into the turbines on wind power farms.  You may be wondering how this could happen.  When wind power was first implemented, the effect on migratory birds and bats was given little consideration.  Soon after some of the first wind power farms were activated, hundreds of dead birds were found littering the grounds at the bases of the towers.  Birds have difficulty negotiating the spinning blades and many times fly into them as a result.

The United States Government Accountability Office published a study in 2005 titled Wind Power Impacts on Wildlife and Government Responsibilities for Regulating and Protecting Wildlife (.pdf 1,721kb).  This study highlighted the fact that wind power has been responsible for a large number of raptor and bat deaths.  However, it also states that mortality rates vary from region to region. 

The U.S. Fish and Wildlife Service Office of Law Enforcement are sometimes involved in wind energy cases because some of the birds killed by the wind power farms are federally protected. The main federal laws protecting birds in these cases are:

When the U.S. Fish and Wildlife Service Office of Law Enforcement believes one of these laws is being violated by a wind energy company, the goal is to work with the energy company and educate the company about the laws and ways to lessen bird deaths caused by the wind power farm.

Some steps the U.S. Fish and Wildlife Service suggests wind companies take are found in the Service Interim Guidance on Avoiding and Minimizing Wildlife Impacts (.pdf 515kb) and include:

1. Proper evaluation of potential wind power sites:

This will give an idea of how many birds and bats fly through the site and of how many birds and bats may collide with the wind power farm.

2. Proper location and design of turbines:

Even if a large number of birds and bats are found to fly through the proposed wind power site, the impact on the birds and bats may be reduced by the placement of the turbines as well as the design of the turbines. (Some newer turbines are taller with slower spinning blades, which some people believe reduces the risk of birds and bats flying into them.)

3. Pre- and post-construction research and monitoring to identify and assess impacts to wildlife:

This will allow for researchers to compare the anticipated impact with the actual impact on birds and bats after the wind power farm is running. Depending on what they find, they may choose to shut down a turbine that is causing more bird and bat deaths than the others, or they may decide to replace smaller turbines with the taller ones mentioned above.

Golden Eagle Killed by Wind Turbine

Bird killed by a wind turbine, U.S. Fish and Wildlife Service

It should be noted that wind power has positive attributes. Wind is a renewable energy source, produces no emissions, is environmentally clean technology, and has been endorsed by the Secretary of the Interior. Click here for more details.

To help identify and resolve potential impacts of wind power to our bird and bat populations, the U.S. Fish and Wildlife Service is ready to work with industry and other government agencies and stakeholders to facilitate project design, location and operation to avoid or minimize negative impacts on birds and bats. Only by working together can we, collectively, ensure development of this "clean" and "green" energy source in a way that is friendly to birds and bats. Click here for more ideas on how we can work together.

The Wind Turbine Guideline Advisory Committee was formed by the Secretary of the Interior in 2007 to develop effective measures to avoid or minimize impacts to wildlife and their habitat.  The guidelines are intended to be used by prospective developers of wind energy projects.  Check back as the Wind Turbine Guideline Advisory Committee finishes its recommendations.

For more information or to contact the U.S. Fish and Wildlife Service, please go to and click on the “contact us” link at the top of the page.


Last updated: November 3, 2009

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