Your TV and cell-phone habits may be contributing to the deaths of millions of migratory birds a year, in collisions with communications towers. A coalition of environmentalists, government scientists, and industry executives is finally taking its own crash course to address the problem, but there's no end to the carnage in sight.
By David Malakoff
On September 21, 1971, lying on his back in the damp grass and looking up into the shifting vapors of the low-hanging clouds, Art Clark could see the problem. Hundreds of feet above, songbirds milled about in the early-morning mist, reluctant to stray far from the glowing red lights on the 1,000-foot television tower that soared overhead. The birds pinwheeled around the structure, swerving perilously close to its heavy frame and thick support cables.
The young ornithologist knew that some of the birds wouldn't survive the encounter. Already, a score of dead and dying warblers lay scattered around the spire's base. Some had shattered their delicate beaks, necks, and wings in high-speed, head-on collisions with cold steel. Others carried telltale smears of cable grease on their otherwise immaculate olive and gold feathers. A few had been reduced to "feather puddles--the owls got them as soon as they hit the ground," Clark recalled one day recently, three decades after that murderous morning, as we gazed up at the thin, orange-and-white candy-striped needle on a gorgeous sunny day.
It is remarkable that the 59-year-old curator at the Museum of Science in Buffalo, New York, can still remember such detail. After all, in the past 35 years he has spent nearly a thousand mornings documenting bird kills at a trio of TV towers perched on rural ridges 25 miles southeast of Buffalo. Following large kills, Clark would search, stooped over, under the towers for hours, a grim reaper straining to spot and collect as many as 1,000 carcasses. "A sore back is a hazard in this business," he murmured as we walked through the ankle-high grass, which obscured anything smaller than a softball.
Earlier, Clark had shown me his sad harvest, stashed in a walk-in freezer in his small museum lab. There, behind the remains of a seven-foot sturgeon caught in nearby Lake Erie and those of a young gorilla from a zoo, were stacks of carefully labeled boxes. They held most of the 20,514 tower-killed birds Clark has collected since he started his tower study in 1967.
Once researchers might have dismissed Clark's collection as merely an ornithological oddity. But it now offers compelling evidence in a growing debate over the threat that the nation's 75,000 radio, television, and cell-phone towers pose to birds, particularly to the 300 or so species that migrate by night between their breeding grounds in North America and their wintering grounds in the tropics. Using Clark's body count and numbers from several other long-term studies, conservation groups and government biologists estimate that communications towers kill 4 to 50 million birds annually. Most are warblers, thrushes, vireos, or other songbirds, and they represent at least 50 species considered threatened or endangered.
To reduce the losses, bird advocates are pushing the telecommunications industry and its federal overseers to rethink rules concerning tower placement and lighting. They are also seeking funds for the studies needed to fully understand why towers kill and what can be done to prevent the thousands of planned spires from adding to the death toll. Plus, the advocates aim to solve some mysteries, such as why big tower kills seem to have declined dramatically in recent years.
Progress, however, has been slow. Key industry and government players have been reluctant to tackle the complex problem, and many are waiting to see how the Bush administration will respond. But a brewing legal challenge that threatens to stall new tower construction and disrupt the multibillion-dollar communications industry could bring things to a head. "We're reaching a crossroads," says Al Manville, a U.S. Fish and Wildlife Service biologist, who has led efforts to address tower kills. "We can keep debating how big the problem is, or we can start getting the information we need to fix it."
Ornithologists have long known that tall, lighted structures are hazardous to birds. In the 1800s lighthouse keepers reported that night flyers would sometimes hurl themselves against the beacons, like moths drawn to a flame. It wasn't until 1948, though, that observers documented the first flock downed by a radio tower, a then-new, 450-foot structure near Baltimore.
Yet the first methodical study of tower kills didn't begin until 1955, when biologist Herbert Stoddard started monitoring a 700-foot TV tower built near the Tall Timbers Research Station, in Tallahassee, Florida. During the next 28 years he and his colleagues tallied more than 44,000 victims representing 189 species. In 1957 physician Charles Kemper mounted a similar watch on a 1,000-foot spire in Eau Claire, Wisconsin. In 38 years he counted more than 121,000 casualties from 123 species, including 12,000 birds killed on a single night in 1963. During that incident, "birds were falling at the rate of four to six a minute," Kemper noted in a scientific report that appeared in Audubon in 1964.
It was a mass kill in January 1998 near three small towers in southwestern Kansas, however, that helped spark the current debate. In a driving snowstorm, an estimated 10,000 lapland longspurs perished, piling up beneath guy wires and along fences. Although biologists would ultimately point to the weather as the kill's primary cause, "it was a wake-up call," says Manville. Adding to the alarm caused by the incident was a tower-building boom fueled by the exploding popularity of cell phones and a federal law requiring television stations to begin high-definition broadcasting by 2003. The switch to HDTV, analysts predicted, would add hundreds of 1,000-foot towers to the landscape.
The boom has had the U.S. Fish and Wildlife Service scrambling to get its arms around the issue. In the past two years the agency has updated reports on the problem, organized a Communications Tower Working Group, and called meetings that have brought researchers, federal and state agencies, tower builders, and conservationists face-to-face. The results have included a laundry list of needed studies and, last September, a 12-point set of voluntary guidelines for tower builders. The recommendations urge companies to cluster towers in "farms" or share existing spires instead of building new ones, to install infrequently flashing white strobes instead of steadily burning red bulbs, and to reduce or eliminate the use of guy wires. The guidelines also recommend against building towers taller than 199 feet, which appear to do the most damage.
In the absence of a definitive fix--or at least one that all parties can agree to--the guidelines make sense, says Frank Gill, Audubon's vice-president of science. "If you don't know what the solution is, that's all the more reason to build fewer towers or keep them in clusters," he says.
The advice, however, is based on a handful of studies that almost everyone agrees are, at best, incomplete. "When it comes to understanding tower kills, we're just like the birds--groping around in the dark," says wildlife ecologist Ron Larkin of the Illinois Natural History Survey, in Champaign.
It's not clear, for instance, why steady red beacons seem to attract birds more than other lights do, although laboratory studies suggest that red wavelengths may disrupt the birds' ability to navigate using the stars or the earth's magnetic fields. The role of weather is also murky, although large kills almost always occur on cloudy or foggy nights. In addition, researchers wonder if tower kills are largely confined to the East during the fall migration--as most existing studies suggest is the case--or whether observers simply haven't looked hard enough in western North America or during the spring. Finally, there is intense speculation about why the number of big kills--defined as 1,000 birds or more--has dropped dramatically in the past 20 years. At Clark's towers, for instance, the last large kill occurred in 1982. Is that because there are fewer birds or less severe weather, or is it because today there are many more attractive light sources that disperse the birds?
To answer such questions, Manville had hoped the government and industry would pony up a pot of money for studies. For example, ornithologist Bill Evans--an independent researcher from Mecklenburg, New York, who has helped publicize the tower-kill issue through a web site, towerkill.com--has proposed a $50,000 study that would equip a TV tower with a variety of lights, then use acoustic-monitoring gear to document how birds react to different colors and flash rates. Other researchers have outlined a multiyear, $15 million to $20 million, national survey to nail down the size of the problem. But research funds remain scarce, in large part because neither the Bush administration nor the fast-moving communications industry consider the studies a priority.
There are exceptions: Several tower and utility companies recently offered to fund fieldwork that might shed light on tower kills in the West and the role of lights. And despite the uncertainty, some major U.S. tower builders, including New York-based American Tower, have altered their construction plans to conform to the voluntary guidelines.
One obstacle to more action, however, is that when tower kills are compared with other causes of declining bird populations, they don't seem like a big deal. For instance, it is estimated that hundreds of millions of birds a year smash into windows and buildings. Pesticides possibly poison an additional 65 million birds, and cats probably claim even more. (Conventional wisdom is that habitat loss is the biggest problem birds face.) Still, such comparisons are beside the point, says Robert Beason, a researcher at the University of Louisiana in Monroe. "Towers may not be causing drastic declines on their own," he concedes. "But they clearly are a contributing factor and, moreover, one that we can probably do something about."
Exactly who should be doing something about towers is a point of contention. Tower builders and communications companies say they want to help but claim they're caught between conflicting agendas. They must please everyone from the Federal Aviation Administration, which requires warning lights on every tower taller than 199 feet, to local planning and historic commissions, which often abhor strobe lighting. "We just want to know which head we are supposed to listen to," says Karen King, government relations director for the Personal Communications Industry Association in Virginia, which primarily represents cell-phone companies and others that build shorter towers.
Some environmentalists say that the Federal Communications Commission (FCC), which regulates tower construction, should be the lead voice. Earlier this year two environmental groups--Friends of the Earth and the Forest Conservation Council--challenged 33 tower permits issued by the FCC, claiming the agency had failed to require adequate environmental-impact studies. The groups also asked the agency to cease issuing permits until it has performed a wide-ranging study of the cumulative impact the towers are having on bird populations.
The FCC hadn't responded as Audubon went to press, but the challenge "has secured the industry's complete attention," says Sheldon Moss, an executive with Crown Castle, a Houston-based company that manages nearly 11,000 towers. "This is an issue we ignore at our own peril." Moss predicts that the pressure will "facilitate a meeting of the minds on what needs to be done."
Meanwhile, Art Clark is preparing for another season of pilgrimages to his towers. It is unglamorous work--hauling the folding ladder he uses to check for bird bodies on rooftops and getting someone to mow the fields so that the casualties can be found. Not so long ago he considered giving it up, because the task was getting expensive and producing fewer specimens for his museum. Now, though, he's kind of looking forward to those occasional cloudy morning commutes. "It's getting exciting," he told me recently. "It would be wonderful if all this effort eventually helps solve the problem."
David Malakoff is a reporter for Science. This is his first article for Audubon.
© 2001 NASI
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