High Quality Content by WIKIPEDIA articles! The whistlers, shrike-thrushes and pitohuis are the c.50 species of birds from the subfamily Pachycephalinae. They are found in the ecozones of Australasia, Oceania and Indomalaya, but the vast majority of the species are found in Wallacea, New Guinea and Australia. Most genera are species-poor or monotypic, but Pachycephala (typical whistlers or thickheads) has a considerable diversity. Recent genetic evidence suggests that the Yellow-flanked Whistler actually should be considered a monotypic subfamily of the Bombycillidae.