The study was initiated in response to a perceived need for the federal government to co-ordinate regulation of wind farms and their impact on wildlife. The report suggests that few wind projects have actually been studied, making it difficult to draw overall conclusions. That leaves regulators lacking necessary expertise because related impacts can vary greatly by region and species, according to the GAO.
"I think the report is good as far as it goes, but in our view it doesn't go far enough," says Tom Gray of the American Wind Energy Association (AWEA). "It doesn't say anything about the benefits of wind energy for wildlife, such as reducing emissions or preserving open spaces and natural habitats."
At present, the federal government regulates wind projects only on federal lands or those that receive federal funding. Of six states reviewed by the GAO, none had ever taken prosecutorial action where wildlife mortalities have occurred.
"It's very fair for the industry to wonder why the positive aspects aren't given more attention," says Jeff Deyette of the Union of Concerned Scientists. "I think the problem is that wind is considered to be a clean energy source. To an extent, whether it's fair or not, the wind industry is held to a little higher standard."
The GAO report goes on to suggest that the US government should take a more active role in assessing the impacts of wind farms on wildlife.
"The report talks about wind not being studied enough," adds Gray. "But we would ask: Compared to what? The overall yearly number of dead birds from flying into buildings ranges from 100 million to a billion. That range is so great because it hasn't been studied enough. The wind industry has been studied pretty thoroughly compared to most other factors."
The Union of Concerned Scientists disagrees. "There are still too many unanswered questions," says Deyette. "The wind industry has been highly cooperative but [its] growth is so fast and turbines are going into so many locations that we still need more studies and to proceed with a little caution. Wind technology has a lot of advantages and there have been a lot of improvements over the last ten or 15 years. It's a good situation now, but it can be even better."