Draft:Algerian nuthatch

The Algerian nuthatch (Sitta ledanti) is a species of bird in the family Sittidae. It is a medium-sized nuthatch, measuring about 12 cm (4.7 in). The upperparts are bluish gray, the underparts of a pale buff color tending to gray. The male can be distinguished from the female by the black front of its crown. 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 Algerian nuthatch is the only bird species endemic to Algeria, where it now inhabits only certain coniferous forests in the north of the country. Its scientific name pays tribute to Jean-Paul Ledant, the Belgian amateur naturalist who discovered the bird in October 1975; 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

The Algerian nuthatch is a medium-sized nuthatch; it measures between 11.5 cm (4.5 in) and 12.5 cm (4.9 in), with a mass of about 18 g. The upperparts are overall bluish gray; 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 eyestripe, separated from the crown by a broad, sharp white supercilium. In females, the crown and eyestripe are the same gray as the back, with the front of the crown sometimes darker (when the plumage is worn), but not as dark as in males. In both sexes, the sides of the head and the throat are white. The iris are brown-black, the legs lead-gray and the bill bluish-gray. There are a few diffuse gray spots on the undertail coverts. Juvenile plumage is similar to that of the female, but duller and with an inconspicuous supercilium; after leaving the nest, bill growth and pigmentation of the bill and legs are incomplete.

In its habitat, the Algerian nuthatch cannot be confused with any other bird. The closest nuthatch geographically is the Eurasian nuthatch (Sitta europaea) which inhabits some localities in the Rif; this species is larger than the Algerian, has no black on the crown and has yellow (or white for some subspecies) underparts tending to orange around the rump. The Algerian nuthatch strongly resembles the Corsican nuthatch (Sitta whiteheadi), but the black crown differs in the males: that of the Algerian species covers the front of the head, as opposed to the whole head in the islander. The underparts are of a warmer pinkish buff in the Algerian species. It is phylogenetically very close to Krüper's nuthatch (Sitta krueperi), with the front of the crown dark in the male and the supercilium marked white, but Krüper's Nuthatch has pale gray underparts and a large russet-brown pectoral patch.

Taxonomy and systematics

Discovery and nomenclature

The Algerian nuthatch was discovered in Algeria by Jean-Paul Ledant, a Belgian agronomist and ornithologist, on October 5, 1975. Identifying it as quite different from other nuthatches, he wrote to the Academy of Sciences to report his discovery. The scientists were incredulous, but working on a revision of Sittidae that would bring Corsican and Krüper's nuthatches closer together, they encouraged Ledant to return to the site. He tried several times during the winter, but the mountain was too snowy to allow exploration. Ledant was finally accompanied by Vielliard in mid-April 1976 to observe broods, which in fact turned out to be later in this mountain range with difficult climatic conditions. They had to wait until July to observe feeding behavior and a few fledglings, as well as to make recordings and call tests with songs of Corsican and Krüper nuthatches. Only a dozen pairs are then counted, but on the 5th and 6th of the month, Vielliard sacrifices all the same pair of adults having finished feeding their young, specimens which will be used as types. Kept in the describer's house, these specimens (holotype and paratype) were seriously damaged after 2005 by insect pests, and were finally given to the National Museum of Natural History, France.

The Algerian nuthatch was formally described in Alauda by Jacques Vielliard in 1976 under its current name of Sitta ledanti. This discovery greatly surprised the world of ornithologists, and the bird seems to come from a "lost world" that has withstood the test of time, the Babor Mountains. Indeed, in ornithology, the observation of an unknown endemic species in the Mediterranean world had not occurred for almost a century, with the richly similar discovery of the Corsican Nuthatch in 1883. In the Palearctic as a whole, the last living bird discovered was the Afghan snowfinch (Pyrgilauda theresae), described in 1937; the Vaurie's nightjar (Caprimulgus centralasicus), described only in 1960, had indeed been discovered as early as 1929.

In December 1976, the Swiss ornithologist Éric Burnier announced in the journal Nos Oiseaux that he had discovered the species independently on June 20 of the same year, before learning from an article in Le Monde of July 28, 1976 that he had been preceded in his discovery and that the species had just been named. 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 meters away. The only known nuthatch in the Maghreb being then the Eurasian nuthatch which populates some localities of the Moroccan Rif and Atlas Mountains, far from Babor Mountains, he knew he was dealing with a new species.

Phylogeny

The Algerian nuthatch is sometimes placed in a subgenus, Micrositta, described by the Russian ornithologist Sergei Buturlin in 1916, 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 "canadensis" group. The German ornithologist Hans Löhrl indicates a certain divergence to Vaurie after studying the ecology and behaviors of American and Corsican birds, and publishing his field notes in 1960 and 1961. 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". He considers it "tempting" to identify the fossil species Sitta senogalliensis (whose membership to the genus Sitta is discussed) described from the Upper Miocene in Italy as the ancestor of the Mesogean nuthatch group.

In 1998, Éric Pasquet studied the cytochrome-b gene in the mitochondrial DNA of about ten nuthatch species, including the various species of the Sitta canadensis group, which he defined as comprising six species, corresponding to those reported in the subgenus Micrositta: canadensis, villosa, yunnanensis, whiteheadi, krueperi and ledanti. The Yunnan nuthatch (Sitta yunnanensis) is not included in the study. Pasquet concludes that the Corsican nuthatch is phylogenetically related to the Chinese nuthatch and the red-breasted nuthatch, these three species forming the sister group of a clade including Krüper's nuthatch and the Algerian nuthatch. The first three species would even be close enough to constitute subspecies, rejecting the "Mesogean" theory of Vielliard and thus confirming the conclusions of Charles Vaurie. For the sake of taxonomic stability, however, all retain their full species status. In 2014, Éric Pasquet et al. published a phylogeny based on nuclear and mitochondrial DNA of 21 nuthatch species and confirmed the relationships of the 1998 study within the "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 in the Sittidae and related families. The second clade, which includes Krüper's and Algerian nuthatches, would have a black front crown in males, this sexual dimorphism being absent in young individuals.

Biogeography

In 1976, the Swiss ornithologist Paul Géroudet suggested that the Mesogean nuthatches once inhabited a fairly continuous belt of conifers around the Mediterranean, which had become fragmented, leaving only a few hard-to-reach refuges where these different species were able to evolve "in isolation". 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 "canadensis group" appeared more than 5 million years ago, at the end of the Miocene, when the krueperi and 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.

Ecology and behavior

Vocalizations

The call is typical of a sittidé, in tsiit tsiit. 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 is a repetition of seven to twelve phrases lasting two to four seconds. The bird may also produce a rapid trill in di-du-di-du-di-du, and when agitated, emit a harsh and repeated chèèh comparable to the call of a Jay.

Food

The Algerian nuthatch has been the subject of few studies allowing us to presume its diet. 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. In winter, insects are scarce and the Algerian nuthatch feeds on coniferous seeds which provide a constant supply. They generally feed alone, but may form mixed feeding flocks outside the breeding season.

Breeding

The breeding season occurs in May-June in Tamentout and Mount Babor, earlier or later depending on weather conditions and food availability; at higher altitudes it may start later. In Taza National Park, the breeding season ends in late June. The nest is built in a tree hole, perhaps from a rough lodge of a spotted woodpecker (Dendrocopos major), in a dead fir tree or in the asperities of an oak or cedar tree, and is usually placed between 4 m (160 in) and 15 cm (5.9 in) from the ground. The bottom is lined with plant debris (wood chips, dead leaves) or animal material such as tawny Owl (Tyto alba) feathers or wild boar (Sus scrofa) hair. While incubation is carried out by the female alone (the male does not have a brood patch), both parents feed the young. Clutches have three or four young at fledging. After the breeding season, adults undergo a full post-nuptial moult and young undergo a partial post-nuptial moult.