Plumage Variation in the Broad-billed Fairy-wren Malurus grayi

Abstract

By comparing 31 of the 37 known fledged specimens, we analysed variation in the Broad-billed Fairy-wren Malurus grayi, endemic to New Guinea. The species occurs in hilly terrain at low elevations, with apparently large distributional gaps on New Guinea's south-eastem peninsula and along much of the southern watershed. We report the second-known southern watershed population, from the Kumawa Mountains. Adult males and females differ mainly in crown color, belly colour and size. As regards geographic variation, the Mt. Bosavi population, campbelli, which we assess as a subspecies rather than a full species, is distinct mainly in its small size, dark-crowned adult males and browner back. The north-east population (pileatus) may be more weakly distinct from the western population (nominate grayi). We also describe age-related variation and individual variation. Thus, like numerous other species of New Guinea's lowland and hill forests, Malurus grayi populations are divided at the isthmus known as Zoogeographer's Gap into western, northern and southern populations, among which the westem and northern populations are the most similar ones.