MODELLING OWL MORTALITY ON ROADS OF ALENTEJO (SOUTHERN PORTUGAL)

Abstract

Owls are one of the birds of prey most commonly found dead along roads. Thus, we investigated the importance of 22 environmental variables on the owl casualties and developed predictive models to estimate the likelihood of owl-vehicle collisions in Alentejo, southern Portugal. We recorded 123 corpses of three owl species, the Barn Owl Tyto alba made up 43% (n=53) of the road-kills, followed by the Little Owl Athene noctua (29%, n=36) and the Tawny Owl Strix aluco (28%, n=34), along 314 km of local roads on a two week basis from August to November 2004. Topography and land use explained the occurrence of owl road kills. Predictive models allowed the identification of several hotspots of owl mortality where a set of combined mitigation measures should be applied to reduce owl mortality. We recommend management of road verges vegetation, implementation of non-transparent screens on roadsides, removal of structures that act as perching sites, and lowering the traffic speed limits.