Rocks and trees: habitat response of Tawny Owls Strix aluco in semiarid landscapes

Breeding territories of Tawny Owls Strix aluco were surveyed in Murcia, SE Spain, in 1992 using imitating calls. In all, 178 territories were detected and although regional density was low, local breeding densities were as hi gh as 17 pairs/100 km(2). The response of Tawny Owls to habitat characteris tics in this semiarid region was related to the scale of the study. The slo pe followed by the forest cover were the best predictor variables for the T awny Owl's breeding density at a 9 km(2) scale, whereas forest cover and th e size of the forests were the best predictor variables when the scale was increased to 100 km(2). Owls seemed to select rugged rocky areas for breedi ng owing to the lack of suitable holes for nesting in the pine forest, but also required a certain amount of forest for hunting. Our results suggest t hat Tawny Owls might be very flexible with respect to habitat selection, ev en at the limits of its distribution range.