Animals

Published on April 27th, 2012 | by James Ayre

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Seven Million Birds Killed Every Year by Communication Towers in North America

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April 27th, 2012 by

 
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Almost seven million birds die every year in North America by running into communication towers during migration. There are 84,000 communication towers in North America, and they can rise up to 2,000 feet.

For context, the Exxon Valdez oil spill killed 250,000 birds and the height of the Empire State building is 1,250 feet.

“This is a tragedy that does not have to be,” said lead author Travis Longcore, associate professor in the USC Spatial Sciences Institute at the USC Dornsife College of Letters, Arts and Sciences.

In a study by the University of Southern California, they found that the taller a tower is, the greater the threat is. There are only 1,000 or so towers above 900 feet, 1.6 percent of the total towers, but they account for 70 percent of the killed birds.

The birds are usually not killed by the tower itself but by the guide wires that hold the tower up. Most of the fatalities appear to occur when cloud cover takes away their view of the stars, which they partly use for navigation.

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The researchers also found that towers with solid red lights rather than blinking ones resulted in far more dead birds.

“In the presence of the solid red lights, the birds are unable to get out of their spell,” Longcore said. “They circle the tower and run into the big cables holding it up.”

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Longcore estimated that bird mortality could be reduced by 45 percent by changing the steady lights to blinking ones. He also recommends that businesses share towers to cut down on the total numbers.

The study focused on the tall towers that are used for TV and radio broadcast, not the shorter towers used for cell phone transmission.

Source: University of Southern California
Image Credits: Longcore et al. PLoS One; doi/10.1371/journal.pone.0034025.g006, USGS

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About the Author

's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.



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