The Shortest Route and Minimal Risk for Birds Crossing the Sea — Research Indicates the Optimal Point for Driving Suppression

A research team from Cornell University analyzed weather radar data from 16 locations along the North American coast over a decade. They found that the migration of songbirds over the sea is concentrated in "denser nights over a shorter period" compared to land, with more movement in the fall than in the spring. Additionally, the average flight altitude over the sea is 13-20% lower than over land, which overlaps with the rotor area of wind turbines, directly increasing the risk of collisions. However, temporarily curtailing offshore wind power during these "short and intense peak" nights could enhance bird safety while minimizing energy loss. In Europe, stopping wind turbines during peak nights is becoming institutionalized, and there are reports that curtailment based on predictive models was effective in the North Sea trials. In the United States, it is estimated that land-based wind turbines cause the deaths of 140,000 to 327,000 birds annually, but many aspects of offshore impacts remain unclear due to the difficulty of retrieving carcasses. The findings from this study, combined with forecasts like BirdCast, provide a concrete pathway for optimizing operations by region and season, planning installations, and improving lighting and altitude avoidance measures.