Sex-, landscape- and climate-dependent patterns of home-range size - a macroscale study on an avian generalist predator

Animal home-ranges are expressions of the biology and ecology of a species, and their size is often considered to be a proxy for habitat quality. Understanding the factors affecting variation in home-range size may aid prediction of the impact of local or global environmental change on studied populations. To this end, we established an international collaborative programme to gather GPS telemetry data on the Lesser Spotted Eagle Clanga pomarina across a large part of its range. The breeding season home-ranges of 58 individuals from Estonia, Lithuania, Poland, Hungary and Romania were estimated using autocorrelated kernel density estimation. Differences in home-range size were analysed using linear mixed-effects models incorporating global (latitude, longitude, climate) and local (habitat heterogeneity, land cover, topography, human disturbance) variables. Home-range was significantly affected by habitat heterogeneity, vegetation cover and human disturbance, and also by climate, increasing with greater temperature seasonality. A quadratic relationship between home-range and Shannon diversity index, found in males, suggests that Eagles use less space in the least and most diverse habitats. Home-ranges were also smaller close to human settlements, but range size was positively correlated with human population density. The first result reflects the positive influence of agricultural management on prey availability, whereas the second reflects negative impacts of disturbance and loss of foraging space. Home-ranges of male Eagles were relatively consistent in size and were more linked to environmental conditions compared with those of females. Female home-ranges were significantly more variable in size and showed less distinctive patterns of relationship with the tested predictors. Sex-dependent variation in home-range may result from the different roles of males and females in breeding activities and territoriality limitations of males. The latter factor both limited and increased the home-range size in different individuals.

Automated summary

Animal home-ranges are influenced by factors such as habitat heterogeneity, vegetation cover, human disturbance, and climate, with differences observed between males and females in terms of range size and relationship with environmental conditions.