Small passerine bird species
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The Eurasian nuthatch or wood nuthatch (Sitta europaea) is a small passerine bird found throughout the Palearctic and in Europe. Like other nuthatches, it is a short-tailed bird with a long bill, blue-gray upperparts and a black eye-stripe. It is a vocal bird with a repeated loud "dwip" call. There are more than 20 subspecies in three main groups; birds in the west of the range have orange-buff underparts and a white throat, those in Russia have whitish underparts, and those in the east have a similar appearance to European birds, but lack the white throat.
Its preferred habitat is mature deciduous or mixed woodland with large, old trees, preferably oak. Pairs hold permanent territories, and nest in tree holes, usually old woodpecker nests, but sometimes natural cavities. If the entrance to the hole is too large, the female plasters it with mud to reduce its size, and often coats the inside of the cavity too. The six to nine red-speckled white eggs are laid on a deep base of pine or other wood chips.
The Eurasian nuthatch eats mainly insects, particularly caterpillars and beetles, although in autumn and winter its diet is supplemented with nuts and seeds. The young are fed mainly on insects, with some seeds, food items mainly being found on tree trunks and large branches. The nuthatch can forage when descending trees head first, as well as when climbing. It readily visits bird tables, eating fatty man-made food items as well as seeds. It is an inveterate hoarder, storing food year-round. Its main natural predator is the Eurasian sparrowhawk.
Fragmentation of woodland can lead to local losses of breeding birds, but the species's range is still expanding. It has a large population and huge breeding area, and is therefore classified by the International Union for Conservation of Nature (IUCN) as being of least concern.
Taxonomy.
The nuthatches are a family of similar-looking birds with short tails and wings, compact bodies and longish pointed bills. They have grey or bluish upperparts, a black eyestripe and strong feet. All are in the single genus "Sitta". Within the genus, the Eurasian nuthatch forms a superspecies with the chestnut-vented, Indian, chestnut-bellied and Kashmir nuthatches and has in the past been considered conspecific with all of these.
The Eurasian nuthatch was described by Carl Linnaeus in his landmark 1758 10th edition of "Systema Naturae" under its current scientific name. "Sitta" is derived from the Ancient Greek name for this bird, , "sittē", and the species name, "europaea", is Latin for "European". "Nuthatch", first recorded in 1350, is derived from "nut" and a word probably related to "hack", since these birds hack at nuts they have wedged into crevices.
In 2014, Eric Pasquet and colleagues published a phylogeny based on examination of nuclear and mitochondrial DNA of 21 nuthatch species. The group "europaea" is related to the two nuthatches of rocky environments, the Western rock nuthatch ("S. neumayer") and the Eastern rock nuthatch ("S. tephronota"), and these two clades diverge from each other by thirteen million years. Within the group "europaea", the white-tailed nuthatch ("S. himalayensis")—and consequently the white-browed nuthatch ("S. victoriae"), although not included in the study—appears to be basal, and the Eurasian nuthatch is closely related to the chestnut-vented nuthatch ("S. nagaensis") and the Kashmir nuthatch ("S. cashmirensis"). The Indian Nuthatch ("S. castanea"), the Beautiful nuthatch ("S. cinnamoventris"), the Burmese nuthatch ("S. neglecta"), and the Siberian nuthatch ("S. arctica") are not included in the study. All the species of the group "europaea" masonry the entrance to their nests. In 2020, a new phylogeny will appear, covering the genus more exhaustively; it includes, in particular, the four species mentioned above. It uses three mitochondrial genes and two nuclear ones. The three species from the south of the Asian continent (Indian, Beautiful and Burmese nuthatches) are related to the Kashmir nuthatch, but surprisingly, the Siberian nuthatch is located on a clean branch, quite distant from the Eurasian nuthatch, from which it was nevertheless long considered a subspecies.
The study by Päckert and colleagues (2020) also includes a fairly exhaustive sampling of the Eurasian nuthatch subspecies. It highlights three large groups of subspecies, not perfectly overlapping with the traditionally distinguished groups on the basis of the coloring of their lower parts. A first group concerns the "European nuthatch", which includes all the European subspecies, whether buff-bellied or white-bellied, as well as the subspecies of the Near East. It is related to the group of the "Asian Nuthatch", including the subspecies inhabiting the northern part of the Asian continent, from Kazakhstan to Korea and Japan, all white-bellied. Finally, a third group of subspecies, the "Eastern nuthatch," includes the Asian subspecies living further south, in North and East China and in Taiwan.
The fossil record for nuthatches is sparse, and in Europe is limited to the extinct "Sitta senogalliensis" from the Lower Miocene in Italy and somewhat later material from France; the family appears to be of relatively recent origin.
Subspecies.
There are more than 20 subspecies, but the precise number is disputed. These taxa can be divided into three main groups; these may have been geographically isolated from each other until relatively recently. Birds of intermediate appearance occur where the group ranges overlap.
The large, white-breasted "S. e. arctica" of north east Siberia is distinctive in appearance and genetically, and may be another subspecies group or even a separate species.
Description.
The adult male of the nominate subspecies, "S. e. europaea" is long with a wingspan. It weighs . It has blue-grey upperparts, a black eye-stripe and whitish throat and underparts. The flanks and lower belly are orange-red, mottled with white on the undertail. The stout bill is dark grey with a paler area on the base of the lower mandible, the iris is dark brown and the legs and feet are pale brown or greyish. Most other members of the "S. e. europaea" group differ only in detail from the nominate form, often with respect to the hue of the underparts, but "S. e. arctica" is quite distinctive. It is large, pale, has a white forehead and a reduced eye-stripe, and it has more white in the tail and wings than any other subspecies. Nuthatches move on trees with short leaps, and do not use their tails for support. In flight, they have a characteristic appearance, with a pointed head, round wings and a short, square tail. Their flight is fast, with wings closed between beats, and is usually of short duration.
"S. e. caesia", the most widespread of the western subspecies, has orange-buff underparts except for a white throat and cheeks. The other western forms mainly differ in the exact shade of the underparts, although some southeastern forms also show a white forehead and supercilium. "S. e. sinensis" and "S. e. formosana", of China and Taiwan respectively, have buff underparts like the western races, but have buff, instead of white, throats.
The female is similar in appearance to the male, but may be identified by her slightly paler upperparts, a browner eyestripe and a more washed-out tone to the flanks and lower belly. In the eastern form, "S. e. asiatica", some males have buff underparts like the female, and birds with this appearance are difficult to sex in the field. Young birds resemble the female, although their plumage is duller and they have paler legs. Individuals can be reliably sexed as female from about 12 days old by their paler and buffer flanks, or, in some white-breasted subspecies, by the creamier hue of their underparts.
Adults have a complete moult after breeding which takes about 80 days, starting from late May onwards and finishing by late September. The moult period for Siberian birds is more compressed, running from June to mid-September. Fledged juveniles moult some of their wing coverts when they are about eight weeks old.
In much of its range, Eurasian is the only nuthatch present. In southeast Europe and southwest Asia, the western and eastern rock nuthatches are larger and paler than the Eurasian species. They also lack white spots in the tail and are usually found in a different, stony habitat, and Krüper's nuthatch is small and has a black cap and reddish breast patch. In southwest China, the chestnut-vented nuthatch is very similar to the European bird, but is darker above, has less white on the face and has greyer underparts.
Similar species.
In most of its range, the Eurasian nuthatch is the only nuthatch present. In Southeast Europe and Western Asia, the Eastern rock nuthatch ("S. tephronota") and the Western rock nuthatch ("S. neumayer") inhabit rocky environments and are larger and paler than species. Eurasian species do not have white dots on their tails. In the same area, the Krüper's nuthatch ("S. krueperi") is smaller, with a dark crown and a large russet patch on the breast. In southwest China, the chestnut-vented nuthatch ("S. nagaensis") is very similar to the torchepot, but has darker upperparts, less white on the face, and more greyish underparts. The Siberian nuthatch ("S. arctica") was once considered a subspecies of the Eurasian nuthatch but differs quite clearly from it, being larger, pale, with a shorter and thinner eye line, a longer bill and a straighter culmen, and more white in the tail than any other subspecies.
Voice.
The Eurasian nuthatch calls frequently, usually with a loud, sharp "dwip" normally repeated twice, sometimes more often if excited. It has a shrill " sirrrr" or "tsi-si-si" alarm call, and a thin "tsit" pre-flight call. The song is a slow whistled "pee-pee-pee" with many variants, including a faster version, and may be intermingled with the call.
The song of the distinctive "S. e. arctica" is said to be noticeably different from that of its relatives, which would help to establish whether it is a full species, but there has been insufficient research into its vocalizations.
Distribution and habitat.
The Eurasian nuthatch's breeding range extends across temperate Eurasia from Great Britain (but not Ireland) to Japan. It is found between the July isotherms, north to about latitude 64°N in western Russia and 69°N in Siberia. It breeds south to the Mediterranean in Europe, although it is absent from the islands, other than Sicily, and in most of Russia the southern boundary is around 54–55°N. In the east, the range includes most of China and Taiwan and much of Korea. It has occurred as a vagrant in Lebanon and the Channel Islands, and the nominate race has been recorded a few times in Finland where "S. e. asiatica" is the normal form.
Most populations are sedentary, apart from some post-breeding dispersal of young birds, and there is a reluctance to cross even short stretches of open water. Northern and eastern breeders are dependent on the cones of the Siberian stone pine, and if the crop fails many birds of the "S. e. asiatica" subspecies may move west into northern Sweden and Finland in autumn, sometimes staying to breed. Siberian "S. e. arctica" may make more limited movements south and east in winter, and "S. e. amurensis", from southeast Russia, is regular in winter in Korea.
The preferred habitat is mature woodland with large, old trees, which provide extensive growth for foraging and nesting holes. In Europe, deciduous or mixed forest is favoured, particularly when containing oak. Parks, old orchards and other wooded habitats may be occupied as long as they have at least a block of suitable trees. Particularly in mountains, old spruce and pine forests are used, and pine is also favoured in Taiwan. In most of Russia, conifers are used for nesting, but population densities are relatively low. Moroccan birds nest in oak, Atlas cedar and fir. Unusual habitats include dwarf juniper in Mongolia and rocky terrain in a limited part of southern Siberia.
The Eurasian nuthatch is primarily a lowland bird in the north of its range, but reaches the tree-line in Switzerland, at or higher, and breeds occasionally at in Austria. It breeds at similar levels in the mountains of Turkey, the Middle East and Central Asia. It is mainly a mountain bird in southern Japan, , and Taiwan, , but in southern China, the chestnut-vented nuthatch is the highland species, with the Eurasian species at lower levels.
Behaviour.
Breeding.
Nuthatches are monogamous, and a pair occupies a breeding territory in which it spends the winter as well. Territory sizes range from in Europe to an average of in the sub-optimal conifer forests of Siberia. The male sings to defend his territory and attract a mate. Both sexes have a courtship display with a floating, quivering flight, and the male will also