[MDOsprey] Communications Towers and Birds: Courtesy of USA Today
David (dstrother@pop.dn.net)
Thu, 02 Sep 1999 18:24:28 -0400
09/02/99- Updated 01:19 AM ET
Towers, antennas silencing songbirds
By Traci Watson, USA TODAY
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 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."