Estimates of bird collision mortality at wind facilities in the contiguous United States

This new study by researchers at the Migratory Bird Center, Smithsonian Conservation Biology Institute in collaboration with the U.S. Fish and Wildlife Service identifies the real risk of industrial scale wind turbines to bird life. The paper will be published in December 2013 but portions can be reviewed by clicking the links on this page.


•    We estimate bird mortality at monopole wind turbines in the contiguous U.S.
•    Between 140,000 and 328,000 birds are killed annually at monopole turbines.
•    Mortality increases with increasing height of monopole turbines.
•    Mortality rates appear to be lower in the Great Plains relative to other regions.


Wind energy has emerged as a promising alternative to fossil fuels, yet the impacts of wind facilities on wildlife remain unclear. Prior studies estimate between 10,000 and 573,000 fatal bird collisions with U.S. wind turbines annually; however, these studies do not differentiate between turbines with a monopole tower and those with a lattice tower, the former of which now comprise the vast majority of all U.S. wind turbines and the latter of which are largely being de-commissioned. We systematically derived an estimate of bird mortality for U.S. monopole turbines by applying inclusion criteria to compiled studies, identifying correlates of mortality, and utilizing a predictive model to estimate mortality along with uncertainty. Despite measures taken to increase analytical rigor, the studies we used may provide a non-random representation of all data; requiring industry reports to be made publicly available would improve understanding of wind energy impacts. Nonetheless, we estimate that between 140,000 and 328,000 (mean = 234,000) birds are killed annually by collisions with monopole turbines in the contiguous U.S. We found support for an increase in mortality with increasing turbine hub height and support for differing mortality rates among regions, with per turbine mortality lowest in the Great Plains. Evaluation of risks to birds is warranted prior to continuing a widespread shift to taller wind turbines. Regional patterns of collision risk, while not obviating the need for species-specific and local-scale assessments, may inform broad-scale decisions about wind facility siting.

Estimatesofbirdcollisionmortality Contiguous U Swindfacilities

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OCT 14 2013
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