Data Zone
Justification of Red List category
This species qualifies as Vulnerable. Its small population is in decline due to logging and fires, reducing the amount of large, mature Corsican Pine Pinus nigra laricio available. Although some forests are regenerating, the slow maturation time of the pine means that potential new habitat does not compensate for the loss of mature pines elsewhere, therefore it is inferred that the population decline will continue.
Population justification
The global breeding population is estimated at 1,500–2,200 pairs, which equates to 3,000–4,400 mature individuals and 4,500-6,600 individuals in total (BirdLife International 2021).
Trend justification
The population size is estimated to have decreased by 2.5% (best estimate) in the past 10 years (BirdLife International 2021). The population is suspected to decline at a greater rate in the future, here tentatively placed in the band 1-19% over ten years, due to continuing deterioration in habitat quality from the loss of Corsican Pine, replaced with Maritime Pine, beech and other vegetation. There is a lack of adequate protection of the species' habitat and threats are continuing, with new ones, such as climate change, emerging.
Small, peripheral populations have gone extinct in the following locations: Santo Pietro d’Accia (due to colonization by beeches); Bois de Verdanese (due to a very small range and isolation); forêt de Pineta in the 2010s, (due to fire, and then cutting of mature stand); the fir forest of Cagna, a very isolated grove and sub-optimum habitat (Seguin et al. 2017, J.-C. Thibault in litt. 2020).
This species is endemic to Corsica (France) (del Hoyo et al. 2008). It has a limited and fragmented breeding range which follows the distribution of Corsican Pine Pinus nigra laricio, occurring on inland mountain ridges from Tartagine south to Ospedale and Mt Cagna, with the main populations focussed around the mountains of Cinto, Rotondo, Renoso and Incudine (Harrap et al. 2020).
Behaviour It forages singly or in pairs, though may join mixed-species flocks outside the breeding season (Harrap et al. 2020). Seeds are cached from late autumn to early spring during periods of sunny weather (when the cones are open) and retrieved during wet or cold weather (Thibault et al. 2006). Its breeding season stretches from April to May, laying a clutch of 5-6 eggs, with mated partners remaining on their territory all year (Harrap et al. 2020). It is generally sedentary except for some dispersal of immature and unmated birds to lower altitudes in winter (Thibault and Bonaccorsi 1999).
Habitat Optimal habitat for this species is mature stands of Corsican Pine Pine laricio with abundant dead and rotting trunks for nest sites, usually in mature stands that are at least 150 years old, or with trunk diameters > 80 cm, or more than 200 years old (Villard et al. 2014, Thibault et al. 2019, Harrap et al. 2020). Densities vary between 0.55 and 1.58 pairs/10 ha and correlate with tree height, vegetation density and dead tree distribution (Thibault and Bonaccorsi 1999, Thibault et al. 2002). Suboptimal habitats include forests where Corsican Pine is associated with Cluster Pine P. pinaster, Balsam Fir Abies alba or beech Fagus sylvatica, and younger, exploited stands of Corsican Pine at elevations (Thibault and Bonaccorsi 1999, del Hoyo et al. 2008). This species is absent in forests with more than 50% of another tree species (Villard et al. 2014). A recent study found highest nuthatch densities in old stands of pure Corsican Pine with very low numbers or no nuthatches in cut areas, areas with young trees or areas without Corsican pine (Villard et al. 2014). Dispersing birds may be found in Holm Oak Quercus ilex and Sweet Chestnut Castanea sativa forests, gardens and orchards (Thibault and Bonaccorsi 1999, del Hoyo et al. 2008).
Diet It feeds largely on insects and spiders during May-October, switching to seeds, especially those of the Corsican Pine, during the rest of the year (Thibault et al. 2006).
Forest fires and logging of mature Corsican pine stands appear to be the primary threats to this species, and have been since the early Holocene (Thibault et al. 2019). Large trees suitable for the species are targeted by the logging industry and since the 1970s local foresters have attempted to rejuvenate the pine forest by shortening the logging rotation, reducing the size of trees available for the species (Bourcet 1996). It has been estimated that 78-122 territories have been destroyed by logging since 1998, and that a further 50-63 territories were lost during the large forest fires of 2000 and 2003, which severely affected another 47-80 territories (Thibault et al. 2004, 2011; Moneglia et al. 2009). In the 2010s these threats have continued and several tens of territories may have been lost (J.-C. Thibault in litt. 2018). It is estimated that only approximately 1,500-2,200 territories are occupied (Seguin et al. 2017). It has been predicted that whenever an area >2 ha is logged in a forest stand suitable for the species, a potential territory is likely to disappear for more than a century due to the slow growth of Corsican pine (Thibault et al. 2011). In harvested forests the species abandons areas when deciduous trees represent more than 50% of the stand (Villard et al. 2014). Maritime Pine P. pinaster is today the main species of conifer, having replaced Corsican Pine and confining them to small regions (Thibault et al. 2019). It is estimated that Corsican Pine forests represent only 200 km2 (Thibault et al. 2019), and favourable habitat may be less than 130 km2 (J.-C. Thibault in litt. 2020).
This species is potentially susceptible to climate change through shifts in suitable climatic conditions (affecting Corsican Pine distribution), however this is not expected to be a serious direct threat (Barbet-Massin and Jiguet 2011). Climate change may also cause an increase in fire frequency and intensity, promoting the Maritime Pine that is more able to persist after fire (Pimont et al. 2011) and so could be a serious future threat to the species (J. Baudat-Franceschi in litt. 2010, Barbet-Massin and Jiguet 2011). Climate change may increase interspecific competition between Corsican Pine and Maritime Pine Pinus pinaster as well as Mediteranean shrub species which in turn could have a negative effect on the species' range (J. Baudat-Franceschi in litt. 2012).
Conservation Actions Underway
EU Birds Directive Annex I. The species is nationally considered to be Vulnerable (IUCN 2011). A national action plan has been instated (Guy et al. 2017) for 2017-2026. There are no natural reserves dedicated to the species on Corsica (J.-C. Thibault in litt. 2016, 2020) although almost the entire global population occurs within the Natural Regional Park of Corse (Harrap et al. 2020). There are no rules nor constraints protecting this species or its habitat in the park (J.-C. Thibault in litt. 2020). The habitat "Pinus laricio" is classified as of Community Interest (Annex 1 of the European “Habitats, Fauna, Flora”). Work is being conducted by forest managers to promote irregular stand cutting, to reduce size of felling coupes, and to keep a fairly good number of old stand islets (Office national des Forêts 2006, Ministère de l’Environnement, de l’Energie et de la Mer 2016). All snags of Corsican pine are now preserved (J.-C. Thibault in litt. 2016). Forest management staff have a computerised management support tool to estimate the number of potential areas of Corsican Nuthatches in the plots being managed (Torre 2014).
Conservation Actions Proposed
Research the minimum size of a Corsican Pine stand required to support a viable population. Develop a plan to prevent forest fires.
Extend current reserves to encompass the habitat of the Corsican Nuthatch, such as the new regional Massif du Rotondu reserve, and ensure they are connected. Ensure that forest management practices are not detrimental to Corsican Nuthatch: in harvested forests reduce the size of felling coupes to <2 ha each; retain at least eight large trees (>70-80 cm diamer at breast height) per hectare in harvested plots; retain snags or dead trees at a similar density within groups of live trees; ensure that the percentage of tree species other than Corsican pine is <50% of the basal area of all trees. Prevent the clearance of dead and rotting trunks in managed forests. Implement official protection for the remaining Corsican Pine forests. Prevent the logging of mature Corsican Pine.
12 cm, 12-14 g. Small, active pine-dwelling nuthatch with a long bill, bright white supercilium. Bluish-grey above and buff below, males have black caps while females show a continuation of the blue colour to the crown. Commonest call a soft 'pu', up to 6 times in a group, while the song is a rapid high-pitched pure toned trill at about 15 notes per second.
Text account compilers
McGonigle, K.
Contributors
Ashpole, J, Baudat-Franceschi, J., Butchart, S., Calvert, R., Derhé, M., Ekstrom, J. & Thibault, J.-C.
Recommended citation
BirdLife International (2024) Species factsheet: Corsican Nuthatch Sitta whiteheadi. Downloaded from
https://datazone.birdlife.org/species/factsheet/corsican-nuthatch-sitta-whiteheadi on 27/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 27/11/2024.