Griffon Vulture movements are concentrated around roost and supplementary feeding stations: implications for wind energy development on Mediterranean islands

Abstract

Griffon Vulture (Gyps fulvus) populations occur on Mediterranean islands, where wind energy is developing fast. As griffons are subjected to collisions with wind turbines while foraging, it is necessary to understand which factors affect their movements to minimize the potential impact of wind farms. We assessed habitat use of 37 griffons (n. GPS locations = 130,218) and their overlap with wind farms in Sardinia (Italy), an island where both Griffon Vulture population and wind energy are significantly expanding. Griffons in Sardinia cover smaller areas (95% isopleth = 956.3 ± 677.7 km2, 50% isopleth = 73.8 ± 48.2 km2) than in mainland Europe, restricting most of their movements within 5–10 km from colonies and roosts. Supplementary feeding stations throughout these areas (n = 37) provide approximately 20 tons of carrion each year, suggesting that griffon movements are strongly determined by food availability. Overall, 6 wind farms (101 turbines) out of the 29 present in Sardinia were built in areas used by foraging griffons. Two of them were positioned near roosts and supplementary feeding stations. As griffon movements concentrate around nesting/roosting sites and feeding stations, wind farms should be excluded around these highly utilized areas, and mitigation measures, including the removal of livestock carrion, should be adopted for those that are built at greater distances. There is also an urgent need for updated data about wind energy location. The creation of supplementary feeding stations could be used to shape the enlargement of the foraging grounds of an increasing Griffon Vulture population on Mediterranean islands and to exclude wind farm areas to mitigate their impacts.