Macro and microgeographical variations in the 'hoot' of Italian and English tawny owls (Strix aluco)

Abstract

We studied the geographical variation of song in tawny owls, comparing temporal and frequency measures of the «hoot» in two races of the species (English and Italian) and in both adjacent and distant populations within each race. We found the two races differed significantly in five of the 13 parameters considered, duration of the second note, lowest frequency of the first note, and frequency modulation amplitude being the most important variables; Italian and English hoots were discriminated with a high success rate (86.7%). The seven populations also differed significantly from each other, particularly in the lowest frequency, but the overall rate of correct classification was lower (78.2%). Microgeographic variations between adjacent populations occurred in both countries: in general, the frequency measures varied through populations according to the habitat, being higher in open farmland and lower in dense woodland or urban habitats. A mosaic pattern of culturally trans mitted hoot variations was therefore recognized, which might suggest the existence of dialects in the tawny owls.