Corsican nuthatch  (Sitta whiteheadi)

The Corsican nuthatch is classified as Vulnerable (VU) on the IUCN Red List (1).

One of only a few endemic island birds in Europe, the Corsican nuthatch (Sitta whiteheadi) is notable for its reliance on another island endemic for its survival, the Corsican pine (Pinus nigra laricio) (4) (5). A small, slight bird with a long, fine bill and long head (2) (3), the Corsican nuthatch has a characteristically short tail which distinguishes it from other western Palaearctic species in the genus Sitta (2).

The Corsican nuthatch is typically blue-grey on the upperparts and pale greyish-white on the underparts, with a buff wash on the flanks and belly. The sides of the head and throat are white. The male Corsican nuthatch has a contrasting black cap and eye stripe, while the female’s crown is much less distinct, being similar in colour to the rest of the upperparts. The eye stripe of the female is usually grey and not well defined. Both the male and female have a prominent white stripe, called the supercilium, running from the beak, above the eye and towards the rear of the head. The outer tail feathers of the Corsican nuthatch are typically black with pale grey tips, and often have whitish spots towards the ends (3). 

The juvenile Corsican nuthatch is similar to the adult, although its plumage is typically duller, with faint brown tips to some of the feathers (3).

The Corsican nuthatch calls with a soft, whistled ‘pu’, which may sometimes be given in a rapid, trilling series ‘pupupupupupu’ just before or during flight. This species sings in a series of clear, high pitched, rapid and sometimes trembling notes ‘hidididididid’ (3). 

The Corsican nuthatch is, as its common name alludes, endemic to the island of Corsica, France. This small bird is found on inland mountain ridges from Tartagine south to Ospedale and Montagne de Cagna. The largest populations of the Corsican nuthatch occur in the mountainous areas around Cinto, Rotondo, Renoso and Incudine (3) (6).

This species is primarily restricted to mature montane forests consisting of Corsican pine (2) (3) (6) (7), an endemic form of the European black pine (Pinus nigra) (7). Within these forests, the Corsican nuthatch is most abundant where dead and rotting tree trunks provide ideal habitat for nest sites (2) (3) (6) (8).

The Corsican nuthatch also occurs at low densities in mixed forest where Corsican pine is associated with cluster pine (Pinus pinaster), balsam fir (Abies alba) or beech (Fagus sylvatica). It may sometimes be found in young forests, heavily managed forests, gardens or orchards (3) (6) (8).

From April to October, the Corsican nuthatch is typically found at elevations of 750 to 1,800 metres, while breeding usually occurs between elevations of 760 to 1,600 metres (3) (8).

A fairly sedentary species, the Corsican nuthatch is present in forests of Corsican pine throughout the year (2) (6). The Corsican nuthatch will search for food singly or in pairs, foraging among branches, needle-clusters, cones and lichens (2) (3) (6). The diet of this species varies depending on the time of year, with insects and spiders taken during the summer and pine seeds forming the most important part of the diet in the winter (2) (3) (6) (9). 

During the autumn, the Corsican nuthatch is known to forage for seeds which are then hidden behind bark or placed on thick branches and covered with small pieces of bark or lichen. Pine cones do not open in wet or cold weather, and so this food storing behaviour ensures that the Corsican nuthatch has access to abundant sources of food throughout the winter months (2) (3) (6).

The Corsican nuthatch breeds from April to May. The nest of the Corsican nuthatch is generally placed in a large dead or dying Corsican pine, typically 1.6 to 30 metres above the ground (3). The male and female both contribute to the excavation of the nest, which may be started from scratch or may make use of an existing woodpecker hole. The nest itself is built from pine needles, wood chips and pieces of bark, and is lined with hair, feathers, moss, lichen or plant fibres (2) (3).

The female incubates the clutch of five or six eggs, which hatch around mid-May. The young nuthatches fledge and leave the nest around 22 to 24 days after hatching (2) (3) (6). The Corsican nuthatch is highly territorial, with mated pairs remaining on their territory all year round (3) (6).    

Destruction and fragmentation of mature Corsican pine forests pose the biggest threat to the Corsican nuthatch, particularly as a result of fire and logging (4) (5) (6) (7) (8). Removal of large trees by the logging industry has resulted in a significant reduction in available habitat for the Corsican nuthatch (5) (6). Since 1998, nearly 200 territories of this species are known to have been either destroyed or severely affected by logging and forest fires (6) (7).

Dead and rotting trees are often removed from woods and forests as part of woodland management programmes, which affects the Corsican nuthatch by destroying potential nest sites. Avalanches may also be a problem in some areas for the Corsican nuthatch, as the slipping snow causes vegetation to erode, leaving wide, open gaps and breaking off dead tree trunks (2) (8). 

Climate change is another potential threat to both the Corsican nuthatch and the Corsican pine on which it depends, with climate change causing shifts in suitable conditions and the potential for forest fires to become more frequent and intense due to drought (4) (5) (6).

The Corsican nuthatch is listed on Annex I on the EU Birds Directive, which aims to protect the habitats of endangered and migratory European species. The Directive also bans activities which directly threaten the birds, such as deliberately killing or capturing listed species, destroying their nests or taking their eggs (10). The Corsican pine habitat of this species is also listed on Annex I of the EU Habitats Directive (11).  The majority of the Corsican nuthatch’s population is found within the Natural Regional Park of Corse (6).

Recommended conservation measures include preventing further logging of mature Corsican pines, as well as researching the minimum area of pine forest required to support a healthy population of the Corsican nuthatch. Additional management measures include preventing the clearance of dead and rotting forests to ensure that suitable nesting sites are retained (6). It has been proposed that Corsican pine forests occurring at high altitudes should be left unexploited, while those at lower altitudes should be managed such that only dead trunks below three metres in height are removed (8).

Find out more about the Corsican nuthatch and other birds:

• BirdLife International - Corsican nuthatch:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=6888