Nicholas School of the Environment and Earth Sciences
Page created on April 24, 2007Patrick Bean - Nicholas School of the Environment and Earth Sciences Master of Environmental Management Candidate 2008. Energy and the Environment.
Katharine Kollins - Nicholas School of the Environment and Earth Science Master of Environmental Management Candidtate 2009, Fuqua School of Business Master of Business Administration Candidate 2009. Energy and the Environment.
Wind Turbines and Their Impacts on Avian and Bat Populations
History and Overview
The penetration of wind power into U.S. electricity markets over the past five years has been phenomenal. One of the reasons America’s new source of electricity generation has done so well is because it is not associated with many of the environmental impacts as our traditional generation sources, especially coal. Wind power does not require large amounts of water for cooling, pollute water and air streams, emit mercury or other harmful pollutants, nor does it produce green house gasses (GHGs) associated with climate change. It is this last benefit that has truly driven the increase of wind power acceptance and will continue to fuel its growth in the near future.
One of the major environmental concerns surrounding wind power is the effect it has on both avian and bat populations. These concerns first arose after a massive wind farm was built in California’s Altamont Pass in the 1980’s. Altamont Pass is both home to and provides migration territory for many sensitive avian species including golden eagles, the red-tailed hawk and others. Wind turbines at Altamont Pass kill an estimated 880 to 1,300 birds of prey each year, including up to 116 golden eagles, 300 red-tailed hawks, 380 burrowing owls, and additional hundreds of other raptors including kestrels, falcons, vultures, and other owl species (CFBD, 2005). Further studies have noted that much of this is due to the location of the wind farm in a major avian migration corridor. Had the avian impact studies done today prior to wind farm development been done at Altamont, many of these negative consequences could have been avoided. Still there are many projects being undertaken at the site to mitigate avian impacts and avoid future collisions.
Reports have documented bat fatalities due to collisions with inanimate objects through out the last hundred years. Bats have collided with power lines, lighthouses, and buildings including the Empire State Building (Erickson et al, 2002). Since wind turbines have been constructed, bats in Colorado, Minnesota, Oregon, Wisconsin and Wyoming have been found dead due to collisions with the turbine blades and support structure. However, bat related fatalities were not raised as a major concern until 2004, when hundreds of bats turned up dead at wind farms in West Virginia and Pennsylvania (Blum, 2005).
Despite the common perception that bats have poor vision (blind as a bat), bats actually have excellent vision due to the use of echolocation (radar) (Encyclopaedia Britannica, 2007). The fatalities come as a surprise since bats require aerial agility to catch their insect prey, yet they cannot seem to dodge the spinning turbine blades in Pennsylvania and West Virginia.
Unlike the avian cases, there have not been any documented reports of endangered bat species fatalities due to collisions with wind turbines (Bat Conversation International, 2007). However, the deaths are still a concern because of the possible impacts on local ecosystems as bat fatalities compound.
The subsequent webpages aim to provide a background about birds and bats and the impacts wind farms have on their populations using information provided from several research studies.