Interbreeding of the Spotted and Yellow-rumped Pardalotes Pardalotus punctatus and P. xanthopygus

Abstract

Two species of spotted pardalotes are currently recognized, Pardalotus punctatus of mesic areas and P. xanthopygus of more xeric areas. Morphologically and ecologically, the two are extremely similar but lack of evidence of inter-breeding has led to reluctance to lump the two taxa. This study examines breeding in a contact area near Bendigo, Victoria. Of seven pairs in a study area of forty ha, only two appeared to comprise individuals of the same taxon. Territories did not overlap and were defended vigorously; all males approached and attacked recorded calls and freeze-dried models of male punctatus and xanthopygus without apparent discrimination. In some individuals in this area display calls and plumages were intermediate between punctatus and xanthopygus. This study suggests the two taxa are not behaving as distinct species in this area of contact. Reports on intergradation from other areas in south-eastern Australia further question the validity of specific separation of P. xanthopygus and P. punctatus.