Wind Turbines and Birds
(This column was first published in the May 9, 2004 issue of The Buffalo Sunday News.)
Both sides agree that, like solar power, wind power is an important alternative to fossil fuel-burning generators that pollute the atmosphere and lead to health problems. This issue is especially timely because today 94 new coal-fired power plants are planned in 36 states. Erie and Chautauqua Counties have already been cited for sub-standard air quality and these new plants, many of them upwind from us in the Midwest, would add still more mercury and greenhouse gasses to our atmosphere.
Beyond their agreement about the need for the benign energy production of wind turbines, however, disagreements arise and we could be headed for gridlock. Perhaps the best example of this is to be seen in the headline over an otherwise reasonable newspaper statement by Elmer Marien, president of the Buffalo Audubon Society. It reads: "Keep Wind Turbines out of Migration Routes". Since birds migrate across broad fronts that cover all of North America, that order could effectively end wind power.
Indeed wind turbines can kill birds.
Today's windmills are giants. You can see ten in action in the Wyoming County Town of Wethersfield. Each 213-foot turbine tower there supports three 77-foot blades. Thus they reach a height of about 290 feet, still, however, well below the usual flight path of both day and night-flying bird migrants. Their blades turn at 28.5 revolutions per minute but, while they appear to be moving slowly, that is an illusion. Their tips swing at over 150 miles per hour and no bird could survive being hit by a blade at that speed.
The often-cited worst case for windmills is Altamont Pass in California where many hawks and eagles have been killed. But even at Altamont, an early windmill location with technology and turbine proximity judged inappropriate today, the Center for Biological Diversity's lawsuit against its operators states: "We are not suggesting closing the Altamont wind farms, rather that turbine owners take reasonable measures to reduce bird kills and adequately compensate for impacts to imperiled bird populations."
Fortunately birds simply avoid the blades of the newer wind turbines.
Studies at more recently designed wind farms tell us that bird mortality at windmills is very low. A summary indicates that the average number of birds killed annually across North America is between one and two per turbine. Arguably the best of the intensive studies was carried out by Canadian Ross James. His year-long field work at a Toronto wind turbine sited in the middle of a fall migration route turned up three birds killed. He also watched birds change course to avoid the turbine blades, an observation shared by many other observers. His final conclusion: "The greatest threat to all wildlife is still loss and/or degradation of habitat."
Against this data we have scare statements like one from a dedicated hawk-watcher in the Chautauqua town of Ripley: "If a bird doesn't get killed in Ripley, he may get killed in Rochester, if not there then at Derby Hill, Prince Edward Island, Toronto...." Statements like this together with intensive lobbying by such deeply concerned birders is deterring the development of wind farms.
But consider what development at Ripley would mean. Over 20,000 hawks, vultures and eagles pass that location each spring to say nothing of passerine migrants. If 35 wind turbines were erected there (more than the number contemplated), the national average would suggest annual deaths of about 60 birds of all species, an infinitesimal fraction of the total number traversing that region.
There is clearly a trade-off here but I believe that a cost-benefit analysis comes down on the side of the wind turbines. I join my birding colleagues in their concern for the death or injury of any bird, but I suggest that wind turbines represent the least of their worries. For example, a single feral cat kills more birds in a week than the average wind turbine kills in over three years.-- Gerry Rising
Since this column was published, an important scientific study of the Chautauqua site has been published. This document provides extensive new data and is well worth close examination.
Among many other articles that speak to the issue of birds and windmills are the following:
and about windmills more generally: