High-resolution modeling of uplift landscapes can inform micrositing of wind turbines for soaring raptors

Abstract

Collision risk of soaring birds is partly associated with updrafts to which they are attracted. To ident ify the risk-enhancinglandscape features, a micrositing tool was developed to model orographic and thermal updraft velocities from high-resolution remote sensing data. The tool was applied to the island of Hitra, and validated using GPS-tracked white-tailedeagles (Haliaeetus albicilla). Resource selection functions predicted that eagles preferred ridges with high orographic uplift,especially at flight altitud es within the rotor-swept zone (40–110 m). Flight activity was negatively associated with thewidely distributed areas with high thermal upli ft at lower flight altitudes (<110 m). Both the existing wind-power plant andplanned extension are placed at locations rendering maximum orographic updraft velocities around the minimum sink ratefor white-tailed eagles (0.75 m/s) but slightly higher therm al updraft velocities. The tool can contribute to improvemicrositing of wi nd turbines to reduce the environmental impacts, especially for soaring Raptors.