A published study has concluded that 573,000 birds and 888,000 bats were killed by wind power in 2012. The figure on birds – which includes 83,000 raptors – is about 30 percent higher than the 444,000 estimate by a U.S. Fish & Wildlife Service biologist in 2009, when the U.S. had about half as much installed wind capacity.
The study, published in the March 2013 issue of Wildlife Society Bulletin, was highlighted this week in a story on the conservative news site Daily Caller.
In the study’s abstract, author and ornithologist K. Shawn Smallwood writes that the goal of his research was to resolve disparate bird and bat fatality estimates that result from widely varying “field and analytical estimates.” To do so he performed various adjustments to totals he had in hand. For instance, he adjusted figures upward to account for carcasses not found, basing the adjustment on field trials that have attempted to quantify how likely killed birds are to be removed or detected.
Smallwood determined that there were “888,000 bat and 573,000 bird fatalities/year (including 83,000 raptor fatalities) at 51,630 megawatt (MW) of installed wind-energy capacity in the United States in 2012.” (The U.S. began 2012 with 46,916 MW of installed wind capacity, according to the U.S. Department of Energy, and ended the year with 60,007 MW.)
“As wind energy continues to expand,” Smallwood concluded, “there is urgent need to improve fatality monitoring methods, especially in the implementation of detection trials, which should be more realistically incorporated into routine monitoring.”
Smallwood’s number is higher than the one put forward by Fish & Wildlife biologist Albert Manville in 2009 [PDF], although per megawatt of installed capacity is actually lower. It’s also much higher than other more recent estimates – and it’s a number that is tiny in comparison to other killers of birds.
In a January 2011 article in Birding magazine, for instance, Paul Kerlinger and two coauthors concluded: “As of early 2010, we estimated that approximately 100,000 birds are killed by wind turbines each year in the U.S., based on an average of about 3+ birds per turbine per year times 30,000 turbines. This number of fatalities does not appear to be causing significant impacts to populations of the species involved, although as more turbines are erected, cumulative impacts must be considered. If the number of birds estimated to be killed by communication towers (4–50 million) is correct, towers cumulatively may kill 40–500 times more birds than do wind turbines currently operating in the U.S.”
And in a comment to the Daily Caller story, the American Wind Energy Association pointed out:
(B)ased on preliminary analysis of data collected from more than 100 wind farms presented at the National Wind Coordinating Collaborative biennial research meeting in November 2012 it is estimated that approximately 200,000 birds collide with turbines annually at current installed wind energy capacity (60+ Gigawatts – enough to power the equivalent of over 15 million homes). This number pales in comparison to other sources like buildings (97-970 million), telecommunication towers (4-5 million), and oil and waste water pits at oil and gas production fields (2-3 million), among other causes of mortality.
Another point to consider is what it would mean to abandon wind and fail to take advantage of the clean energy it offers. It’s this prospect that drives most conservation groups to support wind power. As the Natural Resources Defense Council wrote recently:
(W)e don’t have to choose between healthy and abundant eagle populations and scaling up wind generation to meet our energy needs. That’s a false choice we don’t have to make. What we do need to do is work together—wind energy companies, environmentalists, landowners, policy makers and others—to find the right balance here.