Summary: | The Eagle Owl Bubo bubo is conventionally regarded as an important predator of smaller diurnal birds of prey. In this study, we analysed the relationships between Peregrine pro-ductivity and the proximity to Eagle Owl nests/cliffs in a cliff-nesting Peregrine Falco peregrinus population across the central pre-Alps of Italy and Switzerland over three breeding seasons. There was no effect of Eagle Owls on Peregrine productivity over the whole study area, whereas in a restricted sub-area, where both species occurred at higher densities, proximity to Eagle Owl nests/cliffs and syntopic co-occurrence of the two spe-cies at a given cliff complex resulted in lower Peregrine productivity. Eagle Owl effects at the wider scale were probably masked by other ecological and/or environmental features affecting reproductive success of the Peregrine, whereas these became evident when fo-cusing on a more restricted and homogeneous area. Thus, our study suggests that Eagle Owls may affect population dynamics of diurnal raptors via an effect on productivity.
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