Communications towers silence songbirds
By Traci Watson, USA TODAY
09/02/99- Updated 10:05 AM ET
Songbirds are smart enough to migrate thousands of miles each year without maps.
Many flap all the way from the USA to South America every fall. But somehow these canny
fliers are often stopped dead -- literally -- by a seemingly obvious obstacle: the towers
that transmit TV, radio and cell-phone signals.
Scientists and federal officials are becoming increasingly concerned about the
deaths of migrating birds that run headfirst into communications towers. Many songbirds
migrate after sunset, and on misty nights, some seem to be irresistibly drawn to the
lights atop the taller towers. Circling the mesmerizing glow, the birds crash into the
tower, the guy wires anchoring the tower or even into each other.
Scientists say that a conservative estimate puts the number of birds killed in
tower crashes at 4 million annually.
"We already have 95 threatened and endangered species" of bird, says
Al Manville of the U.S. Fish & Wildlife Service.
Manville argues that even people who aren't bird-watchers should care that
orioles are banging into towers, because "birds are big business." They
pollinate flowers, gobble insects and fuel the annual $21 billion bird-watching industry.
Songbirds are the most frequent victims of tower encounters. Many of them are
champion aerialists that soar thousands of miles a year, sometimes flying nonstop over
broad expanses of ocean. Vireos, warblers and thrushes seem especially prone to crashing
into towers, scientists say.
According to federal statistics, there are roughly 50,000 communications towers
that are at least 200 feet high in the USA. The Federal Aviation Administration requires
all towers of that height to be marked by lights, which may lure birds. The taller the
tower, the more birds it kills, scientists say.
A TV tower in northern Florida is the subject of the longest-running study,
begun in 1955 by an ornithologist because the tower was close to his house. The tower was
670 feet when the study began but was replaced by a 1,000-foot structure in 1960. About
42,000 birds of 189 species died in the 25 years that scientists kept count.
In January 1998, about 10,000 birds, mostly sparrow-like Lapland longspurs, died
in a winter storm at a cluster of towers in western Kansas. Most plunged to the ground,
overcome by the snow. But hundreds crashed into the towers' guy wires and were found in
heaps underneath.
The incident galvanized efforts by ornithologists and bird lovers to staunch the
deaths of songbirds at communications towers. The U.S. Fish & Wildlife Service held a
workshop on the issue last month, and environmentalists are stepping up pressure on the
agencies that oversee towers to take steps that could reduce the number of deaths.
The Federal Communications Commission regulates the towers, but its rules for
environmental review make no reference to impacts on migrating birds.
"The attitude has been one of inertia," says Gerald Winegrad of the
American Bird Conservancy. The FCC's attitude, he says, is "to promote
telecommunication at all costs."
The wireless communications industry says that the deadliness of towers has not
been thoroughly studied. Many scientists agree that there are big gaps in the research.
But they fear the outcome of a 1996 law requiring TV stations to go digital by 2003, which
could result in the construction of hundreds of new towers at least 1,000 feet tall.
There are some measures that could help -- and would please nearby humans, too.
Scientists suggest bundling as many transmitters as possible in one place and using lights
less likely to attract birds. Preliminary studies suggest birds, for reasons not
understood, are drawn more to red lights than to white strobe lights.
The towers are just the most recent hazard to birds. Millions are struck down by
cats, pesticides or encounters with buildings. But ornithologist Bill Evans says,
"That's no reason to prevent some mortality if we think we can do it."
