Abstract
Worldwide expansion in wind-energy generation has raised concerns about bird collisions—in particular, protected species. Bird collision studies are common in Europe and USA, but none had been done in Japan to date. We studied bird fatalities at 42 turbines (52.8 MW) in Tomamae, northern Hokkaido, Japan. For 17 months from July 2007 to November 2008, we performed 24 fatality surveys at an average 21-day interval and ≤100 m from the wind turbines. We found 52 fatalities, including 4 white-tailed eagles (Haliaeetus albicilla). Our estimate of the adjusted annual mortality at Tomamae, which used a modified equation to factor in the complex topography and dense vegetation spread generically over Japan, was 2.20 bird fatalities/MW/year and 0.36 raptor fatalities/MW/year. Bird utilization rates explained most of the variation in fatality rates among species and among locations. The highest fatality rates occurred at the turbines on a costal cliff where the rotor zones of wind turbines overlapped the frequent flight paths of large birds. The development of generalized models can be useful for predicting the impacts of other wind projects on birds, with the exceptions of high-risk situations. However, more surveys of fatality rates and utilization rates are required at this and additional study sites, and over a longer period with shorter search intervals, to develop predictive models of bird collisions with general applicability.