The revised draft of wind energy wildlife impact guidelines released by a US Fish and Wildlife Service Federal Advisory Committee was released in March, and like the first version, contains not a single occurrence of the words “noise” or “acoustic.” The Committee is directed to “recommend effective measures to avoid or minimize impacts to wildlife and their habitats related to land-based wind energy facilities.” How they can provide provide this guidance without considering acoustic impacts is simply unimaginable.  Modern wind turbines are hundreds of feet tall, and create significant sound; even the minimal setbacks for human residences are 1000 feet, with many cases of bothersome noise (especially at night) at a half mile or more.  Wildlife impacts of wind farms are sure to include increased ambient background noise over a fairly large area (half mile to a mile in diameter), which can make it more difficult for predators such as owls and coyotes to find their small prey, and likewise force prey animals to be more vigilant against attack, which has clear energy costs for the animals.  In addition, low-frequency noise radiated into the ground could affect burrowing animals.  Especially in “islands” of woods along ridgelines surrounded by farm land, this acoustic degradation could displace animals from key habitat; even in larger woodlands, steep terrain along ridgelines often contains a different mix of trees and thus habitat that is locally important.  As AEI noted in comments submitted to committee members in February, “In at least some situations/locations, acoustic impacts could be a primary or substantial contributing factor in displacement from habitat, as well as triggering stress that may have synergistic relationships with other impacts.”  Such considerations are basic requirements for effective analysis of impacts on wildlife.  The Committee briefly considered noise impacts, but concluded that no data (specifically involving turbine noise) was available with which to assess the possible effects.  As with ocean noise, though, this lack of specific data does not preclude assessing possible or likely impacts, using studies of other noise sources or even other species than those present at a given project area; NOAA and the Navy routinely take this approach to assessing the impacts of various ocean noise sources.  There is plenty of research on the noise impacts of oil and gas installations, road noise, and aircraft noise on many families of wildlife (birds, rodents, large mammals, etc.).  The National Park Service Natural Sounds office and bioacoustics researchers at universities across the country are good sources of information that this Federal Advisory Committee surely needs to consult before moving forward with guidelines for assessing the impacts of wind farms on wildlife.  These guidelines will shape wildlife impact analyses for years to come, and need to be done right.  

For more on the FWS wind advisory committee, see:
http://www.windaction.org/articles/21154
Industrial Wind Action Group letter to Sec. of Interior Salazar, May 2009

http://www.fws.gov/habitatconservation/windpower/wind_turbine_advisory_committee.html
Advisory Committee website