ITHACA, N.Y. -- If Alfred Hitchcock made disaster films, "Birds vs. Towers" might go something like this: It was a dark and stormy night during fall migration season. Lacking visual cues, the flock homed on the one source of hazy brightness in the sky. Apparently mistaking lights of the communications tower for the moon, some birds smashed head-on into the steel structure. The rest circled the tower like a confused tornado, eventually hitting one of the tower's supporting guy wires, colliding with other disoriented birds or falling to the ground in exhaustion.
Bird scientists gathering at Cornell University last month for the annual American Ornithologists' Union (AOU) meeting looked ahead to fall migration time with renewed dread. 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 -- with even more on the drawing boards.
"The more towers, the more dead birds," said Bill Evans, a consulting ornithologist for the Cornell Laboratory of Ornithology who helped organize the first scientific session of its kind, "Avian Mortality at Communications Towers."
"Many of these 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, citing estimates of bird collisions with manmade objects at 4 million per year.
Flying will become even more hazardous in the next decade, predicted Albert M. Manville, a biologist from the U.S. Fish and Wildlife Service (FWS) 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 FWS biologist said that friends of birds can expect more catastrophes such
as the Jan. 22, 1998, incident when an estimated 10,000 Lapland long
Contact: Roger Segelken
Cornell University News Service