The U.S. Fish and Wildlife Service has constructed voluntary guidelines for wind developers to follow to try and minimize the risk associated with wind power and bird deaths. Although there is no way of knowing the exact number of bird deaths caused by wind power, current estimates are between 30,000 and 60,000 deaths a year. This number may sound astonishingly high, but when compared to the amount of deaths attributed to birds due to skyscrapers or vehicles, it is relatively low.
Currently, wind power generation in the U.S. only accounts for about 1 percent of power in the U.S. or roughly 3 million homes. If renewable energy is mandated to increase to 20 percent to help curb global warming, the number of bird deaths associated with wind power could increase 20 fold, to roughly 900,000 to 1.8 million deaths a year.
The Environment Blog, Oct. 7, 2007