Vulnerability and behavioural avoidance of Golden Eagles near wind farms during the breeding season

Abstract

Wind energy presents a novel stressor to wildlife, sometimes resulting in habitat loss and reduced reproductive output. Vulnerability index is a powerful metric to estimate the susceptibility to harm from stressors. We aim to assess the regional-level exposure, sensitivity and vulnerability to wind farms of breeding Golden Eagles (Aquila chrysaetos). Our study focused on the Gaspé Peninsula (Québec, Canada), a region hosting a vulnerable population of Golden Eagles and 26 wind farms built in the last 25 years. Using nests monitoring and over 13 years of satellite tracking of eight breeding eagles, we show that eagles' exposure to wind farms increases with nest proximity, resulting in higher vulnerability for eagles nesting closer (≤20 km), especially during chick-rearing and post-fledging. Eagles nesting ≤20 km avoided wind farms, using them less than other similar areas, resulting in unused areas in the home range. Our sensitivity and vulnerability assessments revealed that wind farms are positioned in moderate to highly suitable habitats, indicating functional habitat loss. We monitored breeding before, during and after wind farm development, but reproductive outcomes did not significantly vary with development phases. However, overall breeding success in the region appeared to decline over the last two decades, possibly due to a combination of factors. Our study presents the behavioural effects of wind farms on breeding birds of prey while identifying areas most sensitive and nests most vulnerable to wind development in the region. This research underscores the need for pre-construction assessments and continued breeding monitoring for long-term assessment.