African sacred ibis

The African sacred ibis (Threskiornis aethiopicus) is a species of ibis, a wading bird of the family Threskiornithidae. It is native to much of Africa, as well as small parts of Iraq, Iran and Kuwait. It is especially known for its role in Ancient Egyptian religion, where it was linked to the god Thoth. The species is currently extirpated from Egypt.

It is very closely related to the black-headed ibis and the Australian white ibis, with which it forms a superspecies complex, so much so that the three species are considered conspecific by some ornithologists. In mixed flocks these ibises often hybridise. The Australian white ibis is often called the sacred ibis colloquially.

Although known to the ancient civilisations of Greece, Rome and especially Africa, ibises were unfamiliar to western Europeans from the fall of Rome until the 19th century, and mentions of this bird in the ancient works of these civilisations were supposed to describe some type of curlew or other bird, and were thus translated as such. In 1758, Linnaeus was convinced that the ancient authors were describing a cattle egret (Bubulcus ibis), which he thus described as Ardea ibis. Following the work of Mathurin Jacques Brisson, who calls it Ibis candida in 1760, in the 12th edition of his Systema Naturae of 1766 Linnaeus classifies it as Tantalus ibis. These were also unfamiliar birds that did not occur in Europe at the time, in English in these times called the 'Egyptian ibis' by John Latham, and the 'emseesy' or 'ox-bird' by George Shaw.

In 1790, John Latham provided the first unambiguous modern scientific description of the sacred ibis as Tantalus aethiopicus, mentioning James Bruce of Kinnaird who called it 'abou hannes' in his writings describing his travels in Sudan and Ethiopia, and also described Tantalus melanocephalus of India.

Georges Cuvier named it Ibis religiosus in his Le Règne Animal of 1817.

In 1842, George Robert Gray reclassified the bird under the new genus Threskiornis, because the type of the genus Tantalus was designated as to be the wood stork, also formerly known as the wood ibis or wood pelican, and Gray decided these birds could not be classified in the same genus.

In a comprehensive review of 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 four 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.