Northern Bald Ibis - Taxonomy

Taxonomy

The ibises are gregarious, long-legged wading birds with long down-curved bills. Along with the spoonbills they form one subfamily within the Threskiornithidae. The Northern Bald Ibis' closest relative, and the only other member of the genus, is the Southern Bald Ibis, G. calvus, of southern Africa. The two Geronticus species differ from other ibises in that they have unfeathered faces and heads, breed on cliffs rather than in trees, and prefer arid habitats to the wetlands used by their relatives.

The Northern Bald Ibis was described and illustrated by Swiss naturalist Conrad Gessner in his Historiae animalium in 1555, and given the binomial name Upupa eremita by Carl Linnaeus in his 1758 Systema Naturae. It was moved to its current genus by the German herpetologist Johann Georg Wagler in 1832. This species has an interesting history of description, oblivion and rediscovery.

The species probably split into two distinct populations at least 400 years ago and, since then, the two populations have been diverging morphologically, ecologically, and genetically; nevertheless, the Turkish and Moroccan populations of this ibis are not currently classed as separate subspecies. One consistent difference between the eastern and western birds is a single mutation in the cytochrome b gene of their mitochondrial DNA.

Fossils of the Northern Bald Ibis have been found at a Holocene (c. 10,000 years ago) site in southern France, in middle Pleistocene (c. 900,000 ago) strata in Sicily, and in Pliocene-Pleistocene boundary (c. 1.8 million years ago) deposits on the Mediterranean coast of Spain. What appears to be an ancestral form, Geronticus balcanicus, was found in the late Pliocene of Bulgaria, further illustrating the early widespread presence of this genus in Europe, and suggesting that Geronticus eremita may have originated in southeastern Europe or the Middle East.

The genus name, Geronticus, is derived from the Ancient Greek γέρων, meaning old man and refers to the bald head of the aged. Eremita is Late Latin for hermit, from the Greek ἐρημία, meaning desert, and refers to the arid habitats inhabited by this species. The alternative common name Waldrapp is German for forest crow, the equivalent of the Latin Corvo sylvatico of Gesner, adapted as Corvus sylvaticus by Linnaeus.