As many as 7 million birds are killed each year at communications towers across North America. Aviation warning lights on the towers disrupt the birds’ celestial navigation and draw them into a halo of light. The birds then become trapped and circle endlessly, colliding with each other and the tower, or eventually dropping to the ground from exhaustion.
At least 231 North American bird species have been affected, with neotropical migrants making up a large proportion of all species killed. Canadian species killed in significant numbers include the endangered Cerulean Warbler, the threatened Golden-winged Warbler, and the Wood Thrush (a species of special concern).
American Bird Conservancy (ABC) produced the seminal report Communication Towers: A Deadly Hazard to Birds, which details the extent of the bird collision problem in North America. ABC also commissioned the report Scientific Basis To Establish Policy Regulating Communications Towers To Protect Migratory Birds.
Preventing bird deaths from tower collisions can be as simple as changing a light bulb! By switching from steady-burning lights to strobe lights, bird kills can be dramatically reduced without sacrificing aviation safety. Also lights in the blue-green spectrum are less likely to attract birds than white or red lights.
In the United States, ABC proposed and helped design a study that is now ongoing to measure the visibility of towers to pilots when steady-burning red side lights (AT10) are either turned off or made to flash. Modification to these most dangerous of tower lights would dramatically reduce bird deaths.
American Bird Conservancy has achieved an agreement with the telecommunications industry on the construction of new towers that would dramatically reduce bird deaths without imposing major delays or costs to the industry. If accepted by U.S. regulators, the worst towers for birds would for the first time be subject to a true environmental assessment that should reduce impacts on birds. ABC has also helped prevent or modify the construction of several towers that would pose a risk to birds.
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Click here to download a pdf of the U.S. Fish and Wildlife Service Voluntary Guidelines on the siting of towers.