Pecking Order: Energy's Toll on Birds

Icarus would be horrified.

A California solar farm may be killing as many as 28,000 birds a year, The Associated Press reported earlier this week, roasting the birds midflight as they flap through the sun’s magnified rays, turning them into smoking “streamers” as they plummet to the ground.

Federal officials say the plant, in Ivanpah Dry Lake in the Mojave Desert, might amount to a “mega-trap,” attracting first insects with its bright lights, and then the birds that eat them.

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BrightSource Energy, however, one of three companies behind the plant, has since pushed back, arguing the estimates of so-called "avian mortality" may be overblown. What’s more, the company says, other energy sources kill far more birds than solar.

But even if nearly 30,000 birds a year are getting sent to their fiery doom, that’s a mere fraction compared to other U.S. energy sources. Different studies and government agencies used a range of methodologies to reach their conclusions – "There's no standardized way of doing it that everyone can agree to," says Garry George, renewable energy director for Audubon California – but when it comes to bird kills by the electricity industry, here's the approximate pecking order:

Solar: Anywhere from about 1,000 birds a year, according to BrightSource, to 28,000 birds a year, according to an expert at the Center for Biological Diversity.

Wind: Between 140,000 and 328,000 birds a year in the contiguous United States, according to a December 2013 study published in the journal Biological Conservation. Taller turbines tend to take out more birds.

Oil and Gas: An estimated 500,000 to 1 million birds a year are killed in oil fields, the Bureau of Land Management said in a December 2012 memo.

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Coal: Huge numbers of birds, roughly 7.9 million, may be killed by coal, according to analysis by Benjamin K. Sovacool, director of the Danish Center for Energy Technologies. His estimate, however, included everything from mining to production and climate change, which together amounted to about five birds per gigawatt-hour of energy generated by coal.

Nuclear: About 330,000 birds, by Sovacool’s calculations.

Power Lines: Between 12 and 64 million birds a year are felled by transmission lines, according to a study published July 3 in the journal PLOS ONE.

That's plenty of birds. But there's no more effective bird killer than species' lifelong enemy: cats. All told, felines kill 1.4 to 3.7 billion birds a year. Sylvester would be proud.