PREDICTING THE IMPACT OF OFFSHORE WIND POWER DEVELOPMENT THROUGH GPS TRACKING OF BLACK-TAILED GULLS

Abstract

Wind energy generation is increasing globally, and the associated environmental impacts must be considered. The risk of seabirds colliding with offshore wind turbines is influenced by their flight altitude. Flight altitude observations are usually made on boats, and estimates tend to be made during daylight hours in fine weather. As an alternative, global positioning system (GPS) tracking provides flight height information under a range of conditions. In this study, we tracked the foraging behavior of black-tailed gulls (Larus crassirostris) at sea using GPS data loggers. This species is abundant in the offshore waters of the Sea of Japan. Most GPS positions during flight mode (79%) were below or above the blade level (30–220 m), although 21% were in the blade-swept area. There was no clear difference in flight altitude at the blade level between the coastal (50 m in water depth) and offshore areas (50 m). This approach, and the associated data, provide information that may improve avian collision risk assessments for offshore wind farms.