Assessing space use by pre-breeding white-tailed eagles in the context of wind-energy development in Finland

The expansion of wind energy over large areas may be accompanied by major conflicts with birds, including birds of prey. Hence, it is desirable that the space use of species known to be vulnerable to wind energy be assessed in light of current and future developments. Here, we report on the large-scale dispersal movements of pre-breeding white-tailed eagles (Haliaeetus albicilla) in Finland, where a currently modest wind-energy capacity is expected to increase in the near future. We studied white-tailed eagle space use with a particular focus on the potential for annual power production (GWh) at specific locations, as estimated by the Finnish Wind Atlas. Also, we aimed to detect a potential human-wildlife conflict by assessing white-tailed eagle space use against the spatial distribution of existing and recently proposed wind farms. We found that, despite visiting a large proportion of the country, the eagles stayed primarily within coastal areas and islands, restricted to where human infrastructure was present only at very small amounts. Because of the distribution of wind resources, such areas were found to contain considerable potential for power production. The eagles visited most of the areas targeted for wind-energy development. However, these areas did not coincide with a higher-than-average eagle relocation frequency, suggesting that the existing and recently proposed wind farms do not represent an elevated threat to dispersing eagles. Caution should nevertheless be taken against interpreting that co-occurrence poses no threat at any given site, as site selection is paramount to avoid conflicts with avian conservation.