MACRO AND MICROGEOGRAPHICAL VARIATIONS IN THE HOOT OF ITALIAN AND ENGLISH TAWNY OWLS (STRIX ALUCO)

We studied the geographical variation of song in tawny owls, comparing temporal and frequency measures of the ''hoot'' in two races of the s pecies (English and Italian) and in both adjacent and distant populati ons within each race. We found the two races differed significantly in five of the 13 parameters considered, duration of the second note, lo west frequency of the first note, and frequency modulation amplitude b eing the most important variables; Italian and English hoots were disc riminated with a high success rate (86.7%). The seven populations also differed significantly from each other, particularly in the lowest fr equency, 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 p opulations according to the habitat, being higher in open farmland and lower in dense woodland or urban habitats. A mosaic pattern of cultur ally transmitted hoot variations was therefore recognized, which might suggest the existence of dialects in the tawny owls.