Non-territorial GPS-tagged golden eagles Aquila chrysaetos at two Scottish wind farms: Avoidance influenced by preferred habitat distribution, wind speed and blade motion status

Abstract

Wind farms can have two broad potential adverse effects on birds via antagonistic processes: displacement from the vicinity of turbines (avoidance), or death through collision with rotating turbine blades. These effects may not be mutually exclusive. Using detailed data from 99 turbines at two wind farms in central Scotland and thousands of GPS-telemetry data from dispersing golden eagles, we tested three hypotheses. Before-and-after-operation analyses supported the hypothesis of avoidance: displacement was reduced at turbine locations in more preferred habitat and with more preferred habitat nearby. After-operation analyses (i.e. from the period when turbines were operational) showed that at higher wind speeds and in highly preferred habitat eagles were less wary of turbines with motionless blades: rejecting our second hypothesis. Our third hypothesis was supported, since at higher wind speeds eagles flew closer to operational turbines; especially–once more–turbines in more preferred habitat. After operation, eagles effectively abandoned inner turbine locations, and flight line records close to rotor blades were rare. While our study indicated that whole-wind farm functional habitat loss through avoidance was the substantial adverse impact, we make recommendations on future wind farm design to minimise collision risk further. These largely entail developers avoiding outer turbine locations which are in and surrounded by swathes of preferred habitat. Our study illustrates the insights which detailed case studies of large raptors at wind farms can bring and emphasises that the balance between avoidance and collision can have several influences.

Sex difference in natal dispersal distances of Golden Eagles Aquila chrysaetos in Scotland

“…2006) appears largely to create potential functional habitat loss, rather than mortality through collision with turbine blades (Fielding et al . 2021, 2022).…”

“…Native woodlands appear less inimical and are rarer in distribution (McGrady et al 2003) and in older stands can provide nest-sites (Watson 2010). Increasing development of wind farms (Fielding et al 2006) appears largely to create potential functional habitat loss, rather than mortality through collision with turbine blades (Fielding et al 2021(Fielding et al , 2022.…”

Balancing future renewable energy infrastructure siting and associated habitat loss for migrating whooping cranes

“…Wetland habitats used 10.3389/fevo.2022.931260 by whooping cranes along this extensive migration corridor have been highly modified by humans (Dahl, 2011, Lark et al, 2020. For example, a recent assessment revealed that whooping cranes avoid wind-energy infrastructure during migration, resulting in functional losses of suitable stopover habitats (Pearse et al, 2021), a pattern of displacement similarly observed in other avian species (Shaffer and Buhl, 2016, Marques et al, 2020, Fielding et al, 2021. The generation of renewable energy with wind power has rapidly expanded in recent decades, is economically competitive, and provides benefits for mitigating effects of climate change (IPCC, 2011).…”

Approach Distances of Scottish Golden Eagles Aquila chrysaetos to Wind Turbines According to Blade Motion Status, Wind Speed, and Preferred Habitat

“…Wind farm Diversity 2024, 16, 71 2 of 14 development continues to increase as a counter to reliance on fossil fuels' detrimental effects on climate change [3,6,7]. Understanding the drivers behind birds' responses to operational wind farms is essential if further wind farm development proposals are to be assessed robustly (and potential adverse impacts either avoided, minimised, or mitigated) [8][9][10][11][12][13][14][15].…”