NEST-SITE SELECTION BY 4 SYMPATRIC FOREST RAPTORS IN SOUTHERN NORWAY

Differences between 0.1 ha nest-site plots of Honey Buzzards (Pernis a pivorus), European Sparrowhawks (Accipiter nisus), Northern Goshawks ( A. gentilis) and Common Buzzards (Buteo buteo) were compared to random ly sampled 0.1 ha control plots within a 400 km(2) area with 80% fores t and <2% agricultural land in southern Norway. At Honey Buzzard nest sites, forests were more productive than in control plots and there wa s a higher proportion of spruce, older trees and a higher tree density at Northern Goshawk nest sites than in control plots. Nests of Europe an Sparrowhawks were also in sites with higher tree density than expec ted. Common Buzzard nest sites were situated in steeper terrain than c ontrol plots and more often had a southern aspect. For sparrowhawks, n esting in forests with high tree density may be an adaptation to avoid goshawks and pine martens (Martes martes) which are their main nest p redators. For the larger species, nest-site selection may be a respons e both to nest predation risk, microclimate, foraging habitat and food supply.