Predation risk of Tawny Owl Strix aluco nests in relation to altitude, breeding experience, breeding density and weather conditions

摘要

Nest predation was studied in a population of Tawny Owls Strix aluco in the Duna-Ipoly National Park, Hungary during the period 1992-2009, and related to the choice of nesting sites at different altitudes, the breeding experience of males, and weather conditions. The use of nesting sites at high elevations reduced the risk of nest predation in comparison to lower elevations, where breeding territories occur at a higher density. Also, the risk of nest predation decreased as the local breeding experience of males increased. Adverse weather conditions, i.e. long-lasting snow cover, increasing breeding density, and later laying dates enhanced the probability of breeding failure by nest predation. Broods were depredated in the nestling period rather than during incubation.