Changes in density and territory size of the Tawny Owl Strix aluco along an altitude gradient: the effect of forest types and wood cover

The authors correlated the percentage cover of forested areas with Tawny Owl Strix aluco density and territory size measured in deciduous woodlands along the elevation gradient in central Italy. They calculated the amount of wooded areas per owl territory on the basis of four forest types (urban woods, sclerophyllous woods, mesophilous woods, and montane beech woods). Breeding density differed 3-fold among forest types and suggests that wood quality has a direct effect in determining spatial patterns. The amount of wooded areas per territory is fairly stable in all forest types, and indicates a mean requirement of ca. 10 ha per territory. The smallest territories were in ca. 5 ha sized. Minimum habitat requirement may depend locally on wood quality. Management strategies based on the forest type should be undertaken to protect the local high-density populations of this owl.