Krueper's nuthatch  (Sitta krueperi)

Krueper's nuthatch is classified as Near Threatened (NT) on the IUCN Red List (1).

A small, active and restless bird (4), Krueper's nuthatch (Sitta krueperi) is a distinctive species, with a bright rusty-red crescent-shaped band on the breast, a striking black forecrown and a conspicuous white stripe from the base of the bill to above the eye (2) (3) (4).

Krueper's nuthatch has slate-blue upperparts, while the underparts are typically pale grey (2). The male often has a buffish wash to the sides of the breast, flanks and thighs, while the female is often washed with buff or brown on the lower breast and belly. The black forecrown of this species is sharply defined, with a slight blue gloss in the male, and the cheeks, throat and ear-coverts are white. This species has a narrow white eye ring, and a black eye stripe borders the conspicuous white stripe above the eye, becoming broken and less well-defined behind the eye towards the crown. The central tail feathers of Krueper's nuthatch are dark brown, tinged with blue-grey, while the undertail-coverts are chestnut and have pale fringes. The iris is dark cinnamon or brown and the bill is dark grey. The legs and feet are grey-brown (2).

The female Krueper's nuthatch is generally duller than the male, and has a duller forehead, paler eye stripe and paler reddish-orange breast. The feathers of the female are often finely tipped with grey. The juvenile Krueper's nuthatch lacks the distinguishing black forecrown of the adult, and the eye stripes are poorly marked. The breast of the juvenile is much paler (2).

Krueper's nuthatch is a very vocal bird, often most easily located by its call (2) (4), frequently a ‘vite-vite-vite-vite-vite’ or a nasal ‘ue-ue-ue-ue’ (4). When excited or alarmed, Krueper's nuthatch gives a subdued, harsh or hissing ‘cha’ or ‘scharr’, which may accelerate into an excited, scolding, churring rattle (2).

Krueper's nuthatch has a restricted distribution in southern Europe, with the majority of its population occurring in Turkey and the Karachaevo-Circassia and Krasnodar regions of Russia. It also occurs in Georgia and on the island of Lesbos, Greece (5) (6).

Krueper's nuthatch is found in natural coniferous forest and woodland (3) (5) (6) (7), where it nests in slightly decayed old tree trunks, as well as in old cavities already excavated by woodpeckers (5). 

In Turkey, it is often found in association with black pine (Pinus nigra), fir (Abies cilicica), cedar (Cedrus libani), red pine (Pinus brutia) and juniper (Juniperus) (5) (6). It occurs up to elevations of 2,400 metres, although in Turkey it occurs mostly between 1,000 and 1,600 metres (2) (5) (6). In the Caucasus region (Russia and Georgia), Krueper's nuthatch lives mainly in spruce (Picea) forests between elevations of 1,000 and 2,000 metres (3) (5).

A constantly active little bird (8), Krueper's nuthatch is usually found foraging among smaller branches and cones at the tops of conifer trees (2) (3). The male and female will often forage together, peering and pecking at the trunk, branches and cones in search of food (8). During the summer breeding season, Krueper's nuthatch feeds mainly on invertebrates (2) (3), particularly beetles, moths and butterflies (9). It will occasionally catch prey in the air (3) (8). Seeds form a large part of the diet over autumn and winter (2) (3). To extract seeds from a cone, Krueper's nuthatch will insert its bill between the scales to pull out the seeds, after which the seeds are taken to bark crevices and hammered open (2).

Krueper's nuthatch is territorial, particularly during the breeding season (8). It will vigorously defend its territory against intruders by engaging in ‘song-duels’ with its opponents, often perching in an upright posture, quivering its tail and puffing out the feathers on its breast as part of its display (2).

Breeding begins in March or April, depending on the location (2), and the nest of Krueper's nuthatch is usually placed in a hole in a tree, up to 24 metres above the ground. This species may excavate its own hole in a dead trunk or branch, although it will frequently use existing cavities that have been hollowed out by woodpeckers (2) (3) (7) (8) (9). The nest is constructed mainly by the female, out of bark chips, rotten wood and cone scales, and is lined with moss, fibres, hair, wool, fur and feathers (2) (3).

The female Krueper's nuthatch lays the eggs from mid-April to early May, with individuals living close to the coast typically laying their eggs several weeks earlier than those living at higher altitudes (3). The clutch, which usually consists of 5 to 7 creamy white eggs with rusty or purplish spots, is incubated solely by the female until the eggs hatch after 14 to 17 days (2) (3). After hatching, the chicks remain in the nest until they fledge at 16 to 19 days, during which time both adults provide food for the young (2) (3) (8).

Krueper's nuthatch is particularly vulnerable to changes in its coniferous forest habitat (9). Various forestry practices, including deforestation, are placing substantial pressure on the habitat of this species in several parts of its range. Urbanisation and development for tourism pose an additional threat and may further exacerbate habitat loss, especially in coastal areas (5).

Although the small population on Lesbos is thought to have remained fairly stable in recent years, the populations in Turkey and Russia are known to have declined (5). Together, Turkey and Russia are home to around 95 percent of the Krueper's nuthatch population, and further declines may therefore have a significant impact on its future status (5).

Krueper's nuthatch is listed on Annex I of the EU Birds Directive, which aims to provide protection for habitats of endangered as well as migratory species (10). Recommended conservation measures for Krueper's nuthatch include developing a Species Action Plan and a monitoring programme to assess population trends. The potential threats to Krueper's nuthatch also need to be identified and addressed (5).

Further research into the relationship between this species’ habitat requirements and forest composition is needed, to help understand the impact that habitat alterations will have on the population. Protection of mature coniferous forests, especially black pine forests at high altitudes, would greatly benefit Krueper's nuthatch (9).

Find out more about bird conservation:

• BirdLife International - Krueper's nuthatch:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=6890