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Almost Seven Million Birds Perish at Communication Towers in NorthAmerica Each Year Apr 27, 2012 Every year nearly 7 million birds die as they migrate from theUnited States and Canada to Central and South America, according toa new University of Southern California (USC) study published inthe journal PLoS ONE . The birds are killed by the 84,000 communication towers that dotNorth America and can rise nearly 2,000 feet into the sky,according to the authors of "An Estimate of Avian Mortality atCommunication Towers in the United States and Canada." Placing that figure in context, the Exxon Valdez oil spill killed250,000 birds and the Empire State building is 1,250 feet high. "This is a tragedy that does not have to be," said lead authorTravis Longcore, associate professor in the USC Spatial SciencesInstitute at the USC Dornsife College of Letters, Arts andSciences. The taller the tower the greater the threat, the study found. The1,000 or so towers above 900 feet accounted for only 1.6 percent ofthe total number of towers. Yet these skyscraper towers killed 70percent of the birds, about 4.5 million a year, Longcore said. Most of the birds spent winter in places like the Bahamas andsummer in Canada. With names like the Common Yellowthroat and theTennessee Warbler, they could fit in the palm of one's hand. "These birds eat insects and keep our forests healthy," Longcoresaid. "They are quite beautiful. We have a long history ofappreciating birds. Millions of people watch birds." However, the birds are not generally killed by running into thetower itself but the dozens of cables, known as guy wires, thatprop up the thin, freestanding structure, Longcore said. During bad weather, the birds were pushed down by cloud cover andflew at lower altitudes. The clouds also removed navigation cues,such as stars, leaving only the blinking or static red lights oftowers. The blinking did not fool the birds, but towers with a static redlight resulted in more dead birds. "In the presence of the solid red lights, the birds are unable toget out of their spell," Longcore said. "They circle the tower andrun into the big cables holding it up." Longcore estimated that changing the steady-burning lights on the4,500 towers greater than 490 feet tall (about 6 percent of thetotal) could reduce mortality about 45 percent, or about 2.5million birds. The study also recommended that businesses sharetowers to reduce their number and build more freestanding towers toreduce the need for guy wires. In 2005, Longcore and his colleagues started collecting andanalyzing data from field studies that counted the number of birdkills at communication towers across the United States. The teamonly used findings that documented bird kills for at least a yearand in some cases for several decades. The numbers were scrutinized to find the average bird mortalitybased on height, the guy wires and the types of lights affixed tothe tower. The team then matched up tower types, sizes and attributes of 38tower studies, applying those findings to the 84,000 towers acrossCanada and the United States in preparation for the newpublication, which also was submitted to the Federal CommunicationsCommission. "One of the things this country has been great about is saying wecare about not losing species on our watch," Longcore said. "Withthese towers, we are killing birds in an unnatural way. This issenseless." The study, which does not include shorter towers that typically areused for mobile telephone transmission, focused on towers tallerthan 180 feet, which typically provide TV and radio frequencies. The study's authors included Catherine Rich and Beau MacDonald ofThe Urban Wildlands Group, Pierre Mineau, Daniel G. Bert and ErinMutrie of Environment Canada, Lauren M. Sullivan of UCLA, Sidney A.Gauthreaux of Clemson University, Michael Avery of the U.S.Department of Agriculture/Wildlife Services, Albert M. Manville ofU.S. Fish and Wildlife Service, Emilie Travis and David Drake ofthe University of Wisconsin and independent scholar Robert L.Crawford. The study was funded in part by The Urban Wildlands Group,Environment Canada, the American Bird Conservancy and Defenders ofWildlife. The e-commerce company in China offers quality products such as Portable Solar Panel Chargers Manufacturer , China Solar Charging Station, and more. For more , please visit Poly Solar Panels today!
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