Song clinal variability in Passer italiae, a species of probable hybrid origins
Fulgione D., Esposito A.,Rusch C. E., Milone M.Abstract:
Songs are commonly used to measure the clinal variation in hybrid zones. The Italian sparrow populations are currently considered as stabilised hybrids. Their range is delimited by two contact zones: Alpine area and Sicily island with two parental species, Passer domesticus (North European species) and Passer hispaniolensis (North African and south Mediterranean islands specie) respectively. The Italian sparrows (Passer italiae) show intermediate traits according to genotypic and phenotypic clinal variation through the Italian peninsula. In an analysis of song display in Italian sparrow we have used the male territorial marker song as distinctive display between populations. We have recorded and compared the song of male Italian sparrows with those of the two parental species using spectrogram analysis. By multivariate analysis we have found a clinal variation from P. hispaniolensis to peninsular Italian sparrow. This pattern is broken in the Alps where Italian sparrow populations and P. domesticus show similar song structure among each other.