Wind turbines and migratory birds: A serious problem?
Wind turbines are responsible for the deaths of between 10,000 and 40,000 birds each year, according to the American Bird Conservancy.
Debate over the significance of the threat turbine blades pose to migratory birds is about as old as the concept of wind farms themselves. It began in Altamont Pass, Calif., site of one of the first U.S. wind farms, where there were more than 4,000 turbines. Hundreds of bird carcasses were found on the farm grounds, leading bird conservationists to propagate information that wind turbines were inherently deadly to birds.
While the Altamont Pass site kills the largest number of birds — about 4,700 each year, as reported by USA Today — the wind farm sits on a major migratory route for small birds. The latticework blade-model turbines the farm uses are also outdated for energy generation purposes and have been found to actually attract large birds of prey, which use them as perches. Latticework blades have been abandoned by turbine designers in favor of thinner solid blades with slower speeds.
The American Wind Energy Association contends wind turbines are far less lethal to birds than other man-made structures, such as windows (responsible for more than 100 million deaths each year in the U.S.) and power lines (between 130 million and 174 million), or than cats, which remain the number one bird killer.
The Illinois Department of Natural Resources conducted a study in 2007, which found far fewer instances of bird deaths from wind turbines than some feared. The mortality study, conducted at a wind energy installation, found an average of one bird per turbine was killed a year.
However, bat deaths associated with turbines were three times that of the rate of birds, especially during their migratory season, IDNR’s study recorded.
While the department suggested no regulatory action based on the survey’s findings, officials did raise two points of concern. One included the possible development of wind projects at Lake LaSalle, an important wintering area for migratory waterfowl because of the fact the water rarely freezes. The other site was Lake Michigan, where IDNR officials said any consideration of building wind turbines there should note the area is a flyway for birds and bats.
Finally, the department noted the potential for adverse effects to wildlife habitats from the installation of wind turbine towers, as well as the danger that natural areas could suffer erosion, sedimentation, water quality degradation and shadowing from turbine construction and operation.
- Caleb Hale
23 May 2009
Tags: Wind power, Wind energy
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