Bird Cuisinarts, avian blenders, aerial chopper—these are a few of the words and images that wind turbines have conjured up in the minds of local citizens and bird conservationists anxious about the siting of turbines in their communities. And because wind energy has been promoted as an environmentally friendly source of electric power by many politicians, including the sitting president, and vociferously attacked by their political opponents; it might be helpful to review what we know and what we do not know about the effect of wind turbines on birds.
To begin at the beginning, veterans of the alternate energy business vividly remember the era, now 40 years ago, when OPEC decided to remind Americans of our dependence on their oil. One of the results of the experience of waiting in long lines at gas stations was the passage of federal incentives to develop new sources of energy, from clean coal, wind and solar as well as from unconventional sources such as oil locked in tight shale. Sound familiar?
This initial energy revolution did not last much beyond the time that Jimmy Carter wore a sweater to a fireside chat with the American public, but our energy policy of the 1970s produced one very large concentration of wind turbines at Altamont Pass in California that has haunted the industry ever since. If you were an entrepreneur who wanted to get into the alternative energy field in the late 1970s, you looked for places where there were high hills, a sympathetic state government, and large cities close by where your power could be sold efficiently. Altamont Pass, east of San Francisco, is named after a broad saddle in the range of high treeless hills separating coastal California from its great Central Valley. It is an area where steady winds blowing off the Pacific funnel through the pass, increasing the wind’s velocity. Eventually some 5,000 wind turbines were erected in the Altamont Pass Wind Resource Area.
Unfortunately, neither the wind developers nor wildlife regulators knew that Altamont is also an important stopover for migratory golden eagles, California’s endangered state bird, among other large, charismatic raptors. In the years since, approximately 70-80 golden eagles have been killed per year colliding with the rapidly spinning turbine blades, over 2,000 eagle mortalities overall resulting in an almost indelible perception that turbines are “bird Cuisinarts.”
Fast forward four decades.
Increasing gas prices, which since 2008 have twice surged to $4 a gallon, have convinced many Americans that we need to develop new sources of energy from clean coal, wind, solar, and unconventional sources such as natural gas that can be unlocked from tight shale through a new technology called fracking. The federal government has provided incentives to develop these new sources in the form of tax credits and a relaxation of environmental rules that govern the use of fracking fluids and disposal of fracking wastes.
Each one of these energy sources has its own array of opponents, from cottage industry local activists to big time national environmental organizations and business lobbies trying to protect their own businesses, sometimes by surreptitiously funding opponents’ groups.
One of the raps on commercial wind development from bird conservationists is that the U.S. Fish and Wildlife Service has not enforced the Endangered Species Act when it comes to the killing of bald or golden eagles or to the killing of other migratory birds protected by the Migratory Bird Treaty. A spokesman for the American Bird Conservancy has described the government’s approach as providing developers with a “get out of jail free” card. The federal government has recently addressed that concern by developing guidelines for best practices in the siting of wind turbines and for monitoring of wind farms following their construction as an “adaptive management” strategy to reduce impacts if bird mortality occurs.
So what is the scale of the problem of bird mortality from wind turbines? A quick survey of 20 peer-reviewed scientific papers on the effects of wind turbines on birds and bats from around the world during the last decade reveals a variety of estimates of annual mortality ranging from a low of 10,000 deaths per year in the U.S. to a high of 275,000. The most reliable estimates suggest the annual “take” is 100,000 birds from wind farms, 80 percent are songbirds, 10 percent are raptors. That sounds like a lot, and it is. But compared to what? Compared to nuclear power plants, which are estimated to kill 327,000 birds, or coal and natural gas plants, which combine to kill 14,500,000 birds? These are staggering numbers—but minor when compared to lighted communication towers, which kill 40-50 million birds a year in the U.S., or power lines, which kill between 130-174 million birds per year. And we are not going to even talk about your Aunt Sally’s domestic cats, which are estimated to kill more birds than all of the above combined.
So why do wind turbines have a special reputation as bird Cuisinarts? In a word (or two): Altamont Pass. The earlier generation of wind turbines were designed to have rapidly spinning blades set upon lattice towers. Golden eagles on migration soar on the thermals and strong winds over these treeless hills searching for ground rodents. Their legendary eyesight allows them to focus on small targets as they drop from the skies toward their prey, while their peripheral vision is diminished. You could probably do the math of what 15,000 rapidly spinning blades over an important raptor feeding area would mean to these large birds of prey, and it is not pretty. If you’ve seen one YouTube video of an eagle and turbine blade collision, you are unlikely to forget it—ever.
But the way that wind turbines were sited 40 years ago is not the way they are sited today. The authorities responsible for reviewing the expected environmental impacts of wind turbines require multiple-year studies prior to construction to understand the importance of an area to resident and migratory birds. The mortality to birds from an average wind farm has been determined to be between four and 10 birds per year.
Out on Vinalhaven, two years of post-construction monitoring of bird mortality from the three turbines installed by Fox Islands Wind has resulted in approximately two bird mortalities per year. There are quite a number of bald eagle nests in the Vinalhaven-North Haven area and eagles transit over the wind turbines. The blades of the current design of turbines turn slower than those at Altamont and the area under the wind turbines is a habitat not significant to wildlife and thus not a feeding area for eagles. Post construction monitoring of avian impacts will continue on Vinalhaven and a bird protection plan is being submitted to federal authorities to anticipate the adaptive management strategies that may be employed if a significant number of birds—say migrating at night in conditions of reduced visibility—resulted in significant mortality. But so far, the Fox Islands Wind project can say, so good.