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.

They 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.

[16] 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.

[16] This bird is usually silent, but occasionally makes puppy-like yelping noises, unlike its vocal relative, the hadada ibis.

The Iraqi population usually migrates to southwestern Iran, but wandering vagrants have been seen as far south as Oman (rare, but regular) and as far north as the Caspian coasts of Kazakhstan and Russia (before 1945).

For many centuries until the Roman period the main temples buried a few dozen of thousands of birds a year, and to sustain sufficient numbers for the demand for sacrifices by pilgrims from all over Egypt, it was for some time believed that ibis breeding farms (called ibiotropheia by Herodotus) existed.

[24] Strabo, writing around 20 AD, mentions large amounts of the birds in the streets of Alexandria, where he was living at the time; picking through the trash, attacking provisions, and defiling everything with their dung.

[26][27] The species did not breed in southern Africa before the beginning of the 20th century, but it has benefited from irrigation, dams, and commercial agricultural practices such as dung heaps, carrion and refuse tips.

[31] The bird is also native to Yemen; in 2003 it bred in large numbers on small islands near Haramous and along the Red Sea coast near Hodeidah and Aden, where it was often found at waste-water treatment plants.

As such feral populations were established in Italy, France, Spain, Portugal, the Netherlands, the Canary Islands, Florida, Taiwan, the United Arab Emirates and possibly Bahrain.

[1][22][39] Some studies indicate that the introduced populations in Europe have significant economic and ecological impacts,[40] while others suggest that they constitute no substantial threat to native European bird species.

[42] In France the African sacred ibises have become established along its Atlantic coast following the feral breeding of birds which were the offspring of a large free-flying population originating from the Branféré Zoological Gardens in southern Brittany.

A separate population originated from a zoo at Sigean on the Mediterranean coast of France and by 2005 the colony at the Étang de Bages-Sigean was estimated at 250 pairs.

The first pair was seen breeding in the nearby heronry at Oldenico, in Lame del Sesia Regional Park in Novara, NW Italy, in 1989.

Furthermore, in 2000 a group of sacred ibises escaped from a zoo near Münster, some of which apparently crossed the border into Overijssel, as the colours of their rings closely matched.

Birds regularly show up throughout the city and surrounding villages and can often be seen in the early morning in parks and roundabouts picking up scraps left by people the night before.

The diet consists of mainly insects, worms, crustaceans, molluscs and other invertebrates, as well as various fish, frogs, reptiles, small mammals and carrion.

Within a period of 3 years, a few specialized sacred ibis individuals out of the 400 that roosted on the island had fed on at least 152 eggs of the cormorant (other species were even more ovivorous).

[66] In a study of pellets and stomachs contents of nestlings in the Free State, South Africa, food is mostly reported to consist of frogs (mainly Amietia angolensis and Xenopus laevis), Potamonautes warreni crabs, blow fly maggots, Sphingidae caterpillars, and adult beetles.

[65] In France, adult ibises fed largely on the invasive crayfish Procambarus clarkii, for nestlings larvae of Eristalis species are important.

[28] The most important predator of nestlings of the sacred ibis in Kenya is the African fish eagle, which preferentially searches for the largest (sub-)colonies to attack, but in Ethiopia and South Africa it poses less of a threat.

[29] This species was reported to be susceptible to avian botulism in a list of dead animals found around a man-made lake in South Africa which tested positive for the pathogen in the late 1960s and early 1970s.

[68] During a large scale mortality of Cape cormorants from avian cholera in 1991 in western South Africa, small numbers of sacred ibis were killed.

[69] In 1887, the Italian scientist Corrado Parona reported a 3 cm Physaloptera species of nematode in the orbital cavity of a sacred ibis collected in Metemma, Abyssinia (now Ethiopia) in 1882.

[75] For many centuries, sacred ibis, along with two other species in lesser numbers,[76] were commonly mummified by the Ancient Egyptians as a votive offering to the god Thoth.

Thoth, whose head is that of an ibis, is the Ancient Egyptian god of wisdom and reason, and thus of truth, knowledge, learning and study, and writing and mathematics.

[23] It has long been thought, to sustain sufficient numbers for the large and sometimes growing demand for sacrifices by the people, dozens of ibis breeding farms (called ibiotropheia by Herodotus) were established, initially throughout the regions of Egypt, but later centralised around the main temples, each producing around a thousand birds for mummies annually.

[23] An examination of the mitochondrial DNA disputes this and suggests that not only were wild birds caught and added to the captive flocks, but that they provided the bulk of the supply.

[23][79] Mummified specimens of the sacred ibis were brought back to Europe by Napoleon's army, where they became part of an early debate about evolution.

[81] According to Claudius Aelianus in De Natura Animalium, and Gaius Julius Solinus, both quoting much earlier but now lost authors, the sacred ibis procreates with its bill, and thus the bird is always a virgin.