Towers threaten birds,
researchers say
   


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                        There are now more tall towers than ever before especially for cellular 
                   phone and digital television transmission. A growing number of 
                   cell-phone towers and digital television antennas are posing an 
                   increasing threat to millions of migratory birds, according to 
                   ornithologists at Cornell University. Scientists estimate that towers kill 4 
                   million birds in the eastern United States annually.  

                   Although birds have been hitting structures in North America for at 
                   least 100 years, there are now more tall towers than ever before especially 
                   for cellular phone and digital television transmission.  

 

                   "The more towers, the more dead birds," said Bill Evans, a consulting 
                   ornithologist for the Cornell Laboratory of Ornithology. "All of a sudden, 
                   there are a lot more towers being constructed, and we realized there has 
                   been very little research on their effects on birds." To fill the void, he 
                   helped organize the first scientific conference on avian mortality at 
                   communications towers.  

 

                   "Many species face degraded habitats at both ends of their migration flights 
                   and the thousands of towers are a new threat along the way," said Evans.  

                   In the United States, the Federal Communications Commission processes 
                   approximately 70,000 applications each year for new and co-located 
                   wireless, mass media, international and experimental radio facilities, 
                   according to Ava Holly Berland, spokesperson for the FCC Office of 
                   General Counsel in Washington, D.C. That doesn't count the annual 
                   120,000 applications for renewal of existing licenses. Co-location saves 
                   construction costs and is encouraged but not required by the agency's 
                   environmental rules, she says.  

 

                   The Cornell meeting, which took place in August in Ithaca, N.Y., brought 
                   together biologists from government and academia, environmentalists, 
                   representatives of the FCC, the National Association of Broadcasters and 
                   the wireless communications industry. While no consensus was reached, 
                   the scientists were able to trade information, theories and possible fixes for 
                   the problem:  

 

                    Large kills almost invariably occur when migrating birds encounter 
                   inclement weather along frontal boundaries, and the kills are strongly 
                   associated with lights on structures, according to R. Todd Engstrom, a 
                   biologist at the Tall Timbers Research Station in Tallahassee, Fla. He 
                   recommended limiting the number of new towers with "co-location" rules 
                   that require cooperation among applicants for antenna installations, as well 
                   as scientific studies of light's effect on migrating birds.  

 

                    Avian navigation systems might be disrupted by red lights or radio signals 
                   that interfere with the birds' ability to monitor Earth's geomagnetic field, 
                   according to biologist Robert C. Beason of the State University of New 
                   York at Geneseo. That may explain why birds circle to reestablish their 
                   orientation cues and are more likely to collide with towers and guy wires. 
                   Beason called for further studies linking light, radio frequency signals and 
                   bird behavior.  

 

                    Voluntary cutbacks on lighting in tall buildings are saving thousands of 
                   avian lives in downtown Toronto, according to Michael Mesure of the 
                   Fatal Light Awareness Program in Erin, Ontario. When Ontario Hydro 
                   replaced spot lights with rapidly flashing strobe lights on emissions stacks 
                   at six electrical generation stations, bird collisions decreased dramatically.  

                   Flying will become even more hazardous in the next decade, predicted 
                   Albert M. Manville, a biologist from the U.S. Fish and Wildlife Service 
                   Office of Migratory Bird Management in Arlington, Va. He said that 
                   television stations converting to the digital format in the United States plan 
                   to erect more than 1,000 "megatowers," each at least 1,000 feet tall.  

                   The meeting was co-sponsored by the Fish and Wildlife Service, the 
                   American Bird Conservancy and the Ornithological Council.