Rufous and Grey Colour Morphs in the Italian Tawny Owl: Geographical and Environmental Influences

This is the authors' abstract. We don't add key points for this paper.

We examined Tawny Owls Strix aluco from different regions of Europe, especially Italy, in order to determine whether a predominance of either rufous or grey colour morphs depended on geographical, weather or habitat features. Proportions of rufous and grey owls differed throughout Europe showing a mosaic pattern of variation. Although grey owls dominated strongly in the Italian sample, no effect of latitude, altitude, weather or habitat could be found. However, the annual frequencies of the two colour morphs differed significantly over a 101-year period, depending on the weather of the years of collection, with rufous birds suffering a higher mortality in cool-dry years and grey birds in warm-wet years. This provides potential for disruptive selection.