Researchers studying birds killed by power lines are encouraged by recent findings from a study in the Dakotas that could hold implications throughout the Central Flyway, the major migration route that stretches from Canada to Texas.
Wildlife deaths from power lines, wind turbines and other structures are a growing concern across the country, said Al Manville, a senior wildlife biologist with the U.S. Fish and Wildlife Service.
More transmission lines and wind turbines are planned in coming years, which could put several bird species at risk, Manville said.
“We’ve got to address our carbon footprint and deal with climate change,” he said, “but we want to make sure in the process, we don’t create new problems.”
Near Coleharbor, N.D., a study now under way involves placing “diverters” on power lines in an area where large numbers of birds fly between two lakes and are killed in crashes with the lines – not by being electrocuted. The diverters often are brightly colored and designed to spin or move in the wind. They give birds a visual cue to avoid the line.
That study involves collecting the feathered corpses of fallen birds beneath the power lines. Before the diverters were placed on the lines, 429 birds were counted in 2006, said Misti Schriner, a biologist with the Western Area Power Administration. That compares with 344 birds in 2007, after the devices were in place.
Final results won’t be in for several months, but “I do believe there will be a decline,” Schriner said. The American coot, which represents about 20 percent of the dead birds collected, is among the most common species being found in the North Dakota study, Schriner said.
Power lines also can pose hazards to bald eagles and other raptors, said Elizabeth Whealy, who was executive director at the Alaska Raptor Center before being named chief executive officer at the Great Plains Zoo and Delbridge Museum in Sioux Falls. She recalls how a bald eagle named Volta, who was injured by a power line, became an “ambassador” for the Alaska center and helped teach thousands of children about the dangers of power lines and other issues facing raptors.
Today’s research involving power lines could have applications for wind turbines, Manville said. “There’s been talk about looking at that,” he said.
One of the nation’s leading wind power sites is Buffalo Ridge in southwest Minnesota, home to more than 400 wind turbines. It’s among the highest and windiest spots in the region, according to Xcel Energy.
# In San Joaquin County, Calif., researcher Marcus Yee found a 60 percent reduction in bird fatalities under power lines equipped with diverters, according to his January report.
# In central Nebraska, there are concerns about endangered whooping cranes hitting power lines near the Platte River, said Brad Mellema, director of the Iain Nicolson Audubon Center at the Rowe Sanctuary. There are only about 260 whooping cranes – with wingspans that can total 7 feet across – in the entire Central Flyway, he said. Diverters have been put on lines in the area, and Mellema expects to learn more about their effectiveness in coming months.
# In northern California, one study found more than 1,000 raptors were killed annually by wind power facilities there, according to a 2005 Government Accountability Office report. The area includes the nation’s largest concentration of wind turbines – more than 5,000 – in California’s Altamont Pass. “We don’t want to see, whether it’s in the Dakotas or elsewhere, another Altamont Pass scenario,” Manville said.
# In West Virginia, more than 2,000 bats were killed in a seven-month period in an area with 44 wind turbines, according to another study cited in the GAO report. Bats are the primary predator of many insects, said Mike Duran, a zoologist with the Nature Conservancy. The GAO report said deaths of birds and other wildlife vary from one region to another, and it was difficult to draw conclusions about wind power’s effect on wildlife.
Research is important, partly because “birds play a key role in the ecosystem,” said Greg Butcher, director of bird conservation at the National Audubon Society.
“They serve as the canary in the coal mine,” he said. “We find that if humans are doing things in the environment that are bad for birds, it’s a good sign they’re doing things that are bad for humans as well.”
4 July 2008
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