Krüper's Nuthatch

Identification

The Krüper's nuthatch is a small to medium-sized nuthatch, measuring 12.5 centimetres (4.9 in) in length. In males and females, the folded wing measures 71–81 millimetres (2.8–3.2 in) and 68–74 millimetres (2.7–2.9 in) respectively, the tail 33–40 millimetres (1.3–1.6 in) and 33–38 millimetres (1.3–1.5 in). The bill measures 17.9–20.2 millimetres (0.70–0.80 in) and the tarsus 16.9–19.3 millimetres (0.67–0.76 in). The adult male weighs 10–14.3 grams (0.35–0.50 oz). The study of 41 different measurements of many individuals across different localities in Turkey showed small variations in size along the range.<p>The upperparts are blue-gray with a black front crown in adults of both sexes, and the primary and secondary flight feathers are gray-brown. The supercilium is white and underlined by a black eyestripe that is a little less well defined behind the eye. The throat is white and the rest of the underparts are pale gray with a large reddish patch on the crescent-shaped breast. The underwing-coverts are off-white and the undertail is rufous, with white tips. The eye is surrounded by a thin white eye ring, and the iris is dark cinnamon or brown; the bill is dark horn-gray; the upper mandible cutting edge at the base is blue-gray, as is the entire lower mandible base. The legs are gray-brown or dark gray.<p>The sexual dimorphism is not very marked, especially in summer when the plumage is worn, but the female's crown is less black and less sharply defined at the back, whereas the male's crown is sharply defined in glossy black Female underparts are paler and buff, while the male's are pure gray, verging to blue. The juvenile, on the other hand, is more easily distinguished, having much duller plumage and lacking the black crown; at most, the front of it is darker than the rest of the upperparts. Its russet pectoral patch is not very marked, as are the supercilium and the eyestripe. It can be distinguished from the adult female by its fresh plumage when the feathers of the latter are worn and its dark crown. Adults in their first year sometimes have some lingering brown on the feather tips of their greater coverts. Adults undergo a full post-nuptial moult (from mid-May to early September) and sometimes a partial moult before the breeding season (March), which particularly affects the chest. There is also a partial post-juvenile moult involving the middle coverts. With the front of the crown dark and the marked white supercilium, the Algerian nuthatch has cream or buff-colored underparts and lacks a large russet-brown pectoral patch. This patch is characteristic of the Krüper's nuthatch, as is the marked difference between adults and juveniles.

Taxonomy

The Krüper's nuthatch was described in 1863 by the Austrian ornithologist August von Pelzeln under the protonym Sitta krüperi, from type material from İzmir. By naming the species in this way, he pays homage to its discoverer, the German ornithologist Theobald Johannes Krüper. Hans Edmund Wolters proposed the division of the genus Sitta into subgenera in 1975–1982. The Krüper's nuthatch is placed in Sitta (Mesositta) (Buturlin, 1916), which also includes the Algerian nuthatch (S. ledanti), Yunnan nuthatch (S. yunnanensis), red-breasted nuthatch (S. canadensis), Chinese nuthatch (S. villosa) and Corsican nuthatch (S. whiteheadi). The Krüper's nuthatch belongs to the species group canadensis. It is most closely related to the Algerian nuthatch. According to the International Ornithological Congress and Alan P. Peterson, no subspecies are distinguished.<p>In 1998, Éric Pasquet studied the cytochrome b of the mitochondrial DNA of ten species of nuthatches, including the different species of the Sitta canadensis group, which he defined as six species, which are also sometimes treated as the subgenus Sitta (micrositta) (Buturlin, 1916). The Yunnan nuthatch (S. yunnanensis) was not included in the study. Pasquet concludes that the Krüper's nuthatch is phylogenetically related to the Algerian nuthatch, with both species forming the sister group of a clade that includes the Chinese nuthatch, the Corsican nuthatch, and the red-breasted nuthatch. In 2014, Éric Pasquet and colleagues published a phylogeny based on nuclear and mitochondrial DNA from 21 species of nuthatches and confirmed the 1998 study's relationships within the canadensis group, adding the Yunnan nuthatch, which was found to be the most basal of the species.<p>The conclusions of the study are in agreement with the morphology of the species, the red-breasted, Corsican, and Chinese nuthatches sharing, in particular as a derivative characteristic, the entirely black crown only present in males, a unique trait in Sittidae and related families. The second clade, grouping together Krüper's and Algerian nuthatches are thought to have the front of the black crown in males, this sexual dimorphism being absent in young individuals.<p>A study on the phylogeography of the species was published in 2012, involving five sample sites in Turkey. The authors conclude that there are significant genetic diversities between the different localities, showing that the species occurred in at least three refuges during the last glaciation maximum. The southern populations are significantly different from the northern populations of the country, but the different northern populations have intensively mixed their genes after the glacial retreat, and have quite similar nuclear genetic material, although a marked geographical structure is observed by studying their mitochondrial genomes.<p>

Scientific name

Sitta krueperi

Authority

Pelzeln, 1863

Order

Passeriformes

Family

Sittidae

Genus

Sitta

Range and habitat

The Krüper's nuthatch is found almost entirely in Turkey, where it is common in western Anatolia, and where it also lives along the Mediterranean coast in the Taurus Mountains and along the Black Sea coast north of the country, as far as southern Georgia. It also lives on the Greek island of Lesbos and is vagrant in mainland Greece, where it was observed for example at Thessaloniki in October 1955. In 2010, a new nesting area was reported in central Anatolia, in Yozgat province, on the Ak mountains. The site consists of pure Scots pine (Pinus sylvestris) forest, and may support around 560 individuals.<p>The Krüper's nuthatch has a very close relationship with the Turkish pine (Pinus brutia), and the range of the bird almost overlaps that of the tree. Outlying populations of Turkish pine in the Crimea, northwestern Syria, Lebanon, northern Iraq, and Azerbaijan may have once held Krüper's nuthatches, or may still hold undiscovered populations. The Krüper's nuthatch is sedentary, but undertakes small dispersals after the breeding season. Seasonal altitudinal shifts have also been noted, with some birds, possibly adults in their first year, moving down from the high ground in winter to mixed or deciduous forests. The bird is then even commonly observed in the Sochi Arboretum, which has many conifers.<p>The Krüper's nuthatch lives in temperate coniferous forests from sea level up to around 2,000 cm of elevation, locally to the tree line at 2,500 m. In Turkey, it lives mainly between 1,000m and 1,600 m and inhabits the forests of Turkish pine, Caucasian spruce (Picea orientalis), Nordmann fir (Abies nordmanniana), Cilician fir (Abies cilicica), black pine (Pinus nigra) and cedar of Lebanon (Cedrus libani). The population densities in individuals per square kilometer are 12.7, 11.6, 8.5, and 7.8 respectively in the forests of black pine, cilician fir, cedar of Lebanon, and pine of Calabria. At higher altitudes, it can live among junipers (Juniperus). In the Caucasus, it prefers spruce forests between 1,000 m and 2,000 m, but also Nordmann fir and pine forests.

Migration

Resident species

Behavior

Migration pattern: Resident species.

Conservation

Population trend: declining.

Population trend

declining