Habitat use by post-fledging white-tailed eagles shows avoidance of human infrastructure and agricultural areas

Abstract

Habitat use studies provide invaluable information for the conservation of species that suffer from habitat loss or degradation. We used satellite telemetry to study the habitat use of white-tailed eagles (Haliaeetus albicilla) in relation to six habitat classes (artificial surfaces, agricultural areas, forests, semi-natural areas, wetlands and waterbodies) and five forest age classes (0–9, 10–19, 20–59, 60–99 and ≥ 100 years old) during the post-fledging period in Finland. The post-fledging period, defined here as the period between fledging and dispersal from the natal area, is a critical life-history stage. Our primary objective was to provide information that could be integrated into landscape planning, including wind-energy development (which poses a threat to white-tailed eagles). We found that the habitat classes that were selected by the young white-tailed eagles were forests, semi-natural areas (i.e., transitional woodland and bare rock) and wetlands. When using forests, the eagles selected stands of 0–9 years old, presumably due to the use of retention trees surrounded by a clear-cut as perching sites. Conversely, the habitat classes that were avoided were artificial surfaces, agricultural areas and (the immediate vicinity of) waterbodies. We conclude that the conversion of natural habitats into built and agricultural areas is detrimental to young white-tailed eagles because it reduces habitat availability. They, however, appear to be capable of using forests recently impacted by forestry if perch trees are present. Careful landscape planning is needed to protect priority habitats and avoid conflicts with an expanding white-tailed eagle population (e.g., by building wind farms in areas already environmentally disturbed).