Migrating birds collide with tall towers
JB: This is Earth and Sky. Listener Bruce McClure writes, “I . . . understand that communications towers are especially harmful to migrating songbirds…”
DB: Bruce, scientists estimate that collisions with broadcast and communications towers kill more than three million birds each year in the U.S. alone.
JB: It’s a common scenario on cloudy or foggy nights during migration season. Towers over about 60 meters – or about 200 feet tall – turn on flashing lights for aviation safety. The lights refract off water particles in the air and create an illuminated area around the tower. When it’s foggy, the birds can’t see stars – their cues for night migration are gone. Migrating birds will home in on the one source of hazy brightness. Some smash head-on into the tower. Others collide with guy wires, other structures, and other birds.
DB: There are now more tall towers than ever before – especially for cellular phone and digital television transmission. But some researchers say that a slower flash rate of towers’ aviation warning lights can decrease bird collisions. And in downtown Toronto, voluntary cutbacks on lighting in tall buildings are saving thousands of birds.
JB: Special thanks today to the National Fish and Wildlife Foundation and to the U.S. Forest Service. We’re Block and Byrd for Earth and Sky.
The following individuals were interviewed for today’s show. Our thanks to:
Bill Evans
Cornell Lab of Ornithology
Ithaca, NY
Michael Mesure
Fatal Light Awareness Program (FLAP)
Erin, Ontario, Canada
J. Michael Meyers, Ph.D.
USGS Patuxent Wildlife Research Center
Warnell School of Forest Resources
The University of Georgia
Athens, GA
The following books, articles and web sites were used in preparing this script:
Scientists, Communications Industry Struggle With Bird Kills at Towers (NewhouseNews.com)
Telecommunication Towers Affect Avian Community (Wave-Guide.org)
Birdkills at Towers and other Human-made structures (US Fish and Wildelife Service)
Birds vs. Tower: Ornithologists Fear Growth of Telecommunications Industry (Cornell News)
Migrating Birds – A Nova Interview with Bill Evans (PBS.org)
Avian Mortality at Communications Towers – A workshop sponsored by The United States Fish and Wildlife Service, The Ornithological Council, and The American Bird Conservancy.
Applications of avian night flight call monitoring for towerkill mitigation (Avian Mortality at Communications Towers)
Buildings, lights, findings applicable to towers, cumulative effects – the Canadian perspective (Avian Mortality at Communications Towers)
Communication towers, avian mortality, and research needs (Avian Mortality at Communications Towers)
Panel Discussion (Avian Mortality at Communications Towers)
Additional Teacher Resources
U.S. Fish & Wildlife Service: The Trouble with Towers: A Guide to Bird Collisions at Communications Towers
Communications towers are everywhere around us, in our cities and suburbs, along our highways, and along our countryside. They are used for broadcast purposes and for wireless communication. Although the towers serve an important role in our technological society, they also pose a deadly threat to migratory birds. This informative article explains the facts about the threat these communication towers pose to migratory birds, and is a great resource for students and educators of all ages.
U.S. Fish & Wildlife Service: Collisions: Clear the Way for Birds!
A U.S. Fish and Wildlife report published for International Migratory Bird Day 2005 which explains the variety of structures created by humans that are harmful to migratory birds. The report also touches on the implications of the amount of deaths caused by migratory bird collisions.
Wisconsin Natural Resources Magazine: Battered by the Airwaves? The Push to Digital and Cellular Broadcasting Puts Migratory Birds on a Collision Course with Technology
This article discusses the risks migratory birds face on their annual journey, and how the rapid erection of communications towers are making that journey even more perilous.
