Mortality of birds at windfarms has been an area of concern since the first commercial windfarms were constructed in the 1970s. More recently, concern over bat mortality at windfarms has emerged. Studies of avian and bat mortality from midwestern and western North America show regional variation in mortality rates and species affected. We describe the results of a study of bird and bat activity and mortality at the Tennessee Valley Authority's 3-turbine Buffalo Mountain Windfarm in eastern Tennessee, the first commercial windfarm in the southeastern United States.
Mortality of both birds and bats was determined by regular carcass searches from the fall of 2000, when the windfarm began commercial operation, through the fall of 2003. Avian activity was determined by visual observations of migrating raptors during the fall of 2001, by mist-netting birds during the fall of 2001 and 2002, and by analysis of regional migration as detected by NEXRAD radar imagery during the spring and fall of 2001 and 2002. Efforts to monitor nocturnal bird migration through the area with acoustic recording equipment were unsuccessful. Bat activity was determined by the continuous operation of electronic bat detectors and by periodic mist-netting in the windfarm area.