How many birds die from flying near wind turbines? 

—Pam in Shepherdsville, Kentucky

Nearly 600,000 birds a year get thwacked by turbines, and that toll could rise as more turbines are installed, says the American Bird Conservancy (ABC). Gruesome as this sounds, though, turbines' numbers are no match for the annual tolls of communications towers, which kill 6.8 million; power lines, which zap 175 million; windows, 300 million to a billion; and finally cats, which dispatch 1.3 to 4 billion birds a year. And that's not to mention the untold zillions that perish from habitat loss and climate change.

While the toll from turbines is far from a major cause of bird mortality, it's not negligible, so ABC and wind energy experts are working to reduce the rate. For more on cutting bird mortality, visit this site.—Bob Schildgen