They are colonial breeders, which build a stick nest in a tree or bush and lay 2-4 eggs.
Adult Threskiornis ibises are typically 75cm long and have white body plumage. The bald head, neck and legs are black. The bill is thick and curved. Sexes are similar, but juveniles have whiter necks duller plumage. The Straw-necked Ibis differs from the other species in having dark upperparts, and is some times placed in the separate genus Carphibis (Jameson, 1835)as Carphibis spinicollis.
The species are: