The Algerian nuthatch or Kabyle nuthatch (Sitta ledanti) is a species of bird in the nuthatch family Sittidae. It is a medium-sized nuthatch, measuring between and . The are bluish-grey. The male can be distinguished from the female by the black front of its . The species is sedentary; it feeds on arthropods in summer and on seeds in winter. The breeding season takes place around May–June. The nest, built in a hole of tree, shelters a laying of three or four eggs, brooded by the female. The chicks are fed by both parents.
The Kabyle nuthatch is the only bird species endemic to Algeria, where it now inhabits only certain coniferous and broadleaf forests in the Kabylia region in the north of the country. Its scientific name pays tribute to Jean-Paul Ledant, a Belgian amateur naturalist who discovered the bird in October 1975 and named it "la Sittelle Kabyle" (the Kabyle nuthatch); the description of the bird was made by the French ornithologist Jacques Vielliard. The news of this discovery greatly surprised the ornithological world and received international media coverage. The Algerian nuthatch is closely related to Krüper's nuthatch (Sitta krueperi). The bird has only a limited and relict range, threatened by fire, erosion and human action; the species is therefore considered "endangered" by the International Union for Conservation of Nature.
Description
left|thumb|alt=A grey bird with brown body, gleaning|A female Algerian nuthatch, with very little black on the crown, barely spotting the front of the forehead.
The Algerian nuthatch is a medium-sized nuthatch; it measures between and , and weighs about . The are overall bluish grey; the tail has a small subterminal white band bordered with beige. The belly is washed with light salmon-beige up to the undertail coverts; the latter are grey at their base. The male has a black forehead and a dark , separated from the by a broad, sharp white supercilium. In females, the crown and eyestripe are the same grey as the back, with the front of the crown sometimes darker (when the plumage is worn), but not as dark as in males. The juvenile plumage is similar to that of the female, but duller and with an inconspicuous supercilium;
Within its range, the Kabyle nuthatch cannot be confused with any other bird. The closest nuthatch geographically is the Eurasian nuthatch (Sitta europaea) which inhabits Europe widely and some localities in the Moroccan Rif mountains; this species is larger than the Algerian, has no black on the crown and has orange-buff (or white for some subspecies) tending to orange around the rump. Kept in the describer's house, these specimens (the holotype and paratype) were seriously damaged after 2005 by insects, and were finally given to the National Museum of Natural History, France in 2015.
The Algerian nuthatch was formally described in the journal Alauda by Jacques Vielliard in 1976 under its current name of Sitta ledanti. This discovery greatly surprised the ornithological world, as the bird seemed to come from a "lost world" that has withstood the test of time, the Babor Mountains. He published a few drawings and field notes, explaining that he had spotted birds that he had judged to have the characteristics of the Corsican nuthatch and Krüper's nuthatch by song and then approached them only a few metres away. The only nuthatch in the Maghreb then known being the Eurasian nuthatch, which occurs in some localities of the Moroccan Rif and Atlas Mountains about 900 km from the Babor Mountains, he knew he was dealing with a new species. and has no subspecies. American ornithologist Charles Vaurie had grouped in 1957 the Corsican nuthatch, the red-breasted nuthatch (Sitta canadensis) and the Chinese nuthatch (Sitta villosa), which he considered to be very similar, in the "Sitta canadensis" group. In his 1976 description of the Algerian nuthatch, Vielliard devotes a portion of his paper to the possible relationships of the different species and their evolutionary history. He suggests that Vaurie stopped at a "superficial morphological similarity" to bring the Corsican nuthatch closer to the red-breasted nuthatch, and that the Corsican species should rather form with Krüper's nuthatch a group known as the "Mesogean nuthatches", "where Sitta ledanti providentially fits in". which he defined as comprising six species, corresponding to those reported in the subgenus, Micrositta: In 2014, Eric Pasquet and colleagues published a phylogeny based on nuclear and mitochondrial DNA of 21 nuthatch species and confirmed the relationships of the 1998 study within the "Sitta canadensis group", adding the Yunnan nuthatch, which was found to be the most basal of the species.
The conclusions of these studies are in agreement with the morphology of the species, the red-breasted nuthatch, Corsican nuthatch and Chinese nuthatch sharing as a derived character the entirely black crown only present in males, a unique trait among the nuthatches and related families. The second clade, which includes Krüper's and Algerian nuthatches, have the front of the crown black in males, with this sexually dimorphic trait absent in juveniles. In 1998, his phylogeny having been established, Pasquet concluded that the paleogeographic history of the group would be as follows: the divergence between the two main clades of the "Sitta canadensis group" appeared more than 5 million years ago, at the end of the Miocene, when the S. krueperi and S. ledanti clade settled in the Mediterranean basin at the time of the Messinian salinity crisis; the two species making up the clade diverged 1.75 million years ago. The other clade split into three, with populations leaving Asia from the east and giving rise to the North American red-breasted nuthatch, and then, about a million years ago, from the west, marking the separation between the Corsican and Chinese nuthatches. Adults also use a whispered call when an intruder is present, possibly for territorial defense. The song of the Algerian nuthatch is a nasal whistle, composed of a series of rising elements, with a short final note, repeated slowly and can be transcribed into a vuuy-di vuuy-di vuuy-di. It varies according to the season. In summer, it feeds mainly on insects (mainly caterpillars and beetles) and spiders that it finds by surveying the trunks and branches of oak trees. They generally feed alone, but may form mixed feeding flocks outside the breeding season. It was first discovered on Mount Babor, only about from the Mediterranean coast. Its optimal habitat covers only , and the area is home to only 80 pairs according to a 1985 estimate. Then in June 1989 it was found in Guerrouch, within the Taza National Park, The bird could be present in other oak groves of Petite Kabylie, but has not been documented yet.
The Algerian nuthatch lives in oak forests between and altitude and in mixed forests of oak, Italian maple (Acer opalus subsp. obtusatum), and mixed coniferous forests up to the summit of Jebel Babor. It appreciates humid forests with large trees offering cavities, including Algerian fir (Abies numidica), Atlas cedar (Cedrus atlantica), aspen (Populus tremula), Afares oak (Quercus afares), cork oak (Quercus suber) and Portuguese oak (Quercus faginea). A study conducted in Mount Babor between the summers of 1981 and 1982 showed that the factors apparently favourable to the Algerian nuthatch in this massif were "the diversity of tree species, the size (or age) of the trees and indirectly the climate at altitude". The current distribution of the Algerian nuthatch seems to be limited by that of the forests that support it, and the fragmentation of populations may indicate that the species was once more widespread, before deforestation isolated it in the small islands of greenery that it populates today. The nuthatch was included in a 1980 petition by the BirdLife International requesting that the U.S. federal government add 60 foreign species to the federal endangered lists. This request was published in the official gazette of the United States. The petition was published in the Federal Register the following year, but these species, including the Algerian nuthatch, were not added to the endangered species lists until 1995.