Modern turbines have solid instead of latticed towers, so birds can’t rest or nest on them. They can, however, still perch on the nacelle (the bus-sized generator housing at the top of the tower).
Modern utility-scale wind turbines turn at a much lower rpm than older models. Because the blades are so long and are moving 150 to 200 mph at the tips, depending on the model, the impact on birds and bats remains substantial.
Few studies have been done to determine the true effect of industrial wind turbines on birds and bats, and fewer studies still that have been done independently of the wind companies’ control. The evidence is clear, though, that wind turbines present yet another threat to the lives of birds and bats. The risk appears to be much greater in some areas than in others.
The first-year study of the “Maple Ridge” facility on the Tug Hill plateau of New York estimated that 2,000 to 4,000 birds and bats were killed by 120 turbines during the 5-month study period in 2006 (click here for the report; click here for May 1, 2007, testimony to the U.S. House Natural Resources subcommittee on Fisheries, Wildlife and Oceans).
The US Fish & Wildlife Service is concerned about the danger to birds. They have issued siting guidelines which recommend that wind turbines should not be installed near wetlands, on mountain ridges, near shorelines, or in other locations known as concentration areas for wildlife or at sites subject to frequent fog or low-lying clouds during spring and fall migrations.
Mountain ridges and coastal areas, where industrial turbines are often installed, are features of the landscape that concentrate many birds. Songbirds mostly migrate at night and low enough to collide with the blades of large wind turbines. The presence of large wind turbines may cause birds to avoid the site, thus losing a foraging resource and requiring extra energy to fly around it. The cumulative effect of multiple facilities could have a serious toll on bird populations. The activities of prairie birds, including mating and nesting, are easily disturbed — even at a great distance — by the construction and continuing operation of an industrial wind power facility, which can spread over hundreds, often thousands, of acres.
Wind power is a unique threat to raptors (hawks, eagles, falcons, owls, and vultures) — many of them already endangered — and other large birds, such as ducks, geese, swans, and cranes. The risk of collision not only threatens individual birds but also augments existing threats to their populations. The cumulative effect of multiple facilities may threaten the viable breeding of several species already in decline.
Promoters of industrial wind power often try to divert our attention to the carnage wrought by office tower windows, cars, and housecats, as if a greater wrong excuses the lesser. Even using the scant data inconsistently compiled by consultants hired by the wind power developers, it is clear that industrial wind turbines kill many more birds and bats per unit than these other causes, particularly raptors (such as eagles and hawks) and migrating bats and songbirds.
Promoters of industrial wind power try to justify the threats to birds and bats with the claim that they are actually saving even more birds by cleaning the air and reversing global warming. They are wrong in that rationalization, because wind power does not replace other sources of electricity to such a meaningful degree (see the “Output” FAQ).
The threat to bats has turned out to be a problem the industry can’t deny. FPL Energy ended access to its facilities after independent research documented that thousands of bats were killed in just a couple of months at one location and that this pattern of mortality was being seen at other sites as well. To divert attention from this outrage and their lack of action to remedy it, FPL Energy announced in January 2006 that it would fund some bat conservation projects. That effort will not, however, mitigate the harm they are causing, let alone justify or reduce it.
A revealing story comes from Carleton College in Northfield, Minnesota, which constructed a 1.65-megawatt wind turbine in September 2004 out in the middle of a corn field two miles from campus. In October 2005, the Winona Daily News described a tour led by project director Rob Lampa. Lampa told the group that they had seen no sign of a single bird or bat death since the turbine was switched on. But as they were leaving, one of the group from Winona pointed out something on the ground to one of the county commissioners with her. It was a dead bat. Nearby was another. As one of NWW’s correspondents commented, Lampa will have to make sure the clean-up crew does a better job before the next tour!
As with birds and bats, there are no reliable studies of the effect of industrial wind turbine facilities on other animals. The installation of such large structures in wild areas, along with supporting roads and transmission infrastructure and the clearing of trees on mountain ridges, inevitably has a negative effect, if only because of the loss, degradation, and fragmentation of habitat, especially ecologically vital interior forest. The turbines also move (producing noise and vibration) and are lit by strobes day and night, adding to the distressing impact they likely have.
Until good studies are done, we have anecdotal evidence such as the following about the effect of a wind facility on Backbone Mountain, West Virginia: “I looked around me, to a place where months before had been prime country for deer, wild turkey, and yes, black bear, to see positively no sign of any of the animals about at all. This alarmed me, so I scouted in the woods that afternoon. All afternoon, I found no sign, sight, or peek of any animal about.”
© National Wind Watch, Inc.