plumage patterns by Holyoak in 1970, it was noted that the three taxa were extremely similar and that the Australian birds resembled Threskiornis aethiopicus in adult plumage and T. melanocephalus in juvenile plumage, he thus proposed they all be considered part of a single species T. aethiopicus. At the time this was generally accepted by the scientific community, however in 'The Birds of the Western Palearctic' compendium of 1977, Roselaar advocated splitting the group into 4 species, recognising T. bernieri, based again on the then known geographical morphological differences. In 1990, Sibley & Monroe, in the general reference 'Distribution and Taxonomy of Birds of the World' followed Roselaar in recognising four species, which they repeated in 'A World Checklist of Birds' of 1993. This taxon being split from T. melanocephalus and T. molucca was further advocated by another morphological study by Lowe and Richards in 1991, where, like Holyoak, they looked at plumage again but used much more skins, but unlike him concluded that the differences were such to merit separate species status for the three taxa, especially as they could find no intergradation in morphological characters in possible contact zones in SE Asia. They also cite purported differences in courtship displays between the Australian and Asian birds. Based on these characteristics they recommended the Malagasy birds be considered a subspecies of T. aethiopicus. In 2003, Birdlife International elected to adopt the narrow taxonomic concept as advocated in Sibley & Monroe 1993. Description An adult individual is long with all-white body plumage apart from dark plumes on the rump. Wingspan is and body weight . Males are generally slightly larger than females. The bald head and neck, thick curved bill and legs are black. The white wings show a black rear border in flight. The eyes are brown with a dark red orbital ring. Sexes are similar, but juveniles have dirty white plumage, a smaller bill and some feathering on the neck, greenish-brown scapulars and more black on the primary coverts. This bird is usually silent, but occasionally makes puppy-like yelping noises, unlike its vocal relative, the hadada ibis. Distribution Native The sacred ibis breeds in Sub-Saharan Africa and southeastern Iraq. A number of populations are migrant with the rains; some of the South African birds migrate 1,500 km as far north as Zambia, the African birds north of the equator migrate in the opposite direction. The Iraqi population usually