Habitat and nest site preferences of Red-backed Shrike (Lanius collurio) in western Denmark

Abstract

In this study we evaluate nest site and habitat preferences of Red-backed Shrike (Lanius collurio) in the national park Mols Bjerge, Denmark. In total, 28 nests were found during 2010 and 2011. To determine nesting site preferences, the species composition of vegetation in scrub used for nesting was compared to that of nearest unused scrub. To evaluate habitat preferences, a Resource Selection Probability Function (RSPF) was modelled based on presence/absence data. The habitat factors were represented by Light Detection And Ranging (LIDAR) derived measures of vegetation height and topographic wetness as well as distance to nearest road/path, as an indicator of human disturbance. Scrub used as nesting sites were characterized by thorny shrub species such as Prunus spinosa and Rubus fruticosus. RSPF showed that shrike presence was positively correlated with vegetation heterogeneity and high topographic wetness, and that it was unaffected by the distance to the nearest road/path. These results provide some guidelines for management, showing that Red-backed Shrike for nesting preferred habitats with high wetness, possibly linked to food availability, and heterogeneous vegetation, consistent with their need for low vegetation for hunting and higher vegetation for hunting perches and nest sites, with thorny shrubs especially important for the latter.