SummaryEndemic to the island of Corsica in the western Mediterranean, the Corsican Nuthatch Sitta whiteheadi only occupies mature stands of Corsican Pine Pinus nigra laricio which cover a very small area. We present estimates of the distribution and population size of the Corsican Nuthatch, based on both field investigation and analysis of vegetation maps for the 103 county and municipality forests identified. Between spring 1997 and summer 2008, 48 forests were systematically investigated to map nuthatch territories, requiring 20 months of fieldwork. In the 55 forests not explored, we estimated the number of territories from analysis of digital maps with a calculated mean density from six spot-mapping censuses previously made in mature forests. The total estimated number was estimated to be 1,557-2,201 territories, distributed across 45 forest fragments (5 group of connected stands) totalling 185 km 2 . At distances varying from 250 m to 16 km from each other, fragments were separated by unfavourable vegetation (shrubs, trees other than pines) or rocky outcrops. The area of these fragments varied from seven to 3,159 ha. Of the 45 fragments, 19 held fewer than 10 nuthatch pairs, 20 had 10-99 territories, and only six had more than 100 territories. We suggest that nuthatch numbers have declined by 10% in the past 10 years because of a reduction in suitable habitat due to fires and logging. The Corsican Nuthatch currently fulfils the criteria established by IUCN to qualify as ''Vulnerable''.

The Corsican Nuthatch Sitta whiteheadi is a bird endemic to Corsica Island and has a very small population. Its habitat, Corsican pine Pinus nigra laricio forest, is currently restricted to less than 16,000 ha and is threatened by forest fires. In this article, we aim (1) to evaluate the effects of a large wildfire on a Nuthatch population, and (2) to identify the habitat features that influence the presence/absence of the Nuthatch after fire, so as to promote appropriate forestry practices after fire. The study has been conducted on a study plot of 300 ha which is part of a larger area severely burnt in August 2003. Habitat characteristics have been investigated on 39 plots of 1,225 m 2 occupied by the bird, and 22 randomly chosen plots without the Nuthatch. We observed a decrease of 37.5% in Nuthatch abundance the first spring after the fire, but the impact showed great local variation as a function of fire severity. Logistic modelling showed that the presence of Nuthatch mainly depended on the degree of crown alteration: the Nuthatch tended to be present when at least one pine had less than 2.5 m of crown burned. We have no evidence of any direct fire-induced mortality, but several effects of fire can explain this population decrease, namely, the reduction of canopy volume, the decrease of the amount of pine seeds, and the reduction of nest-site availability. These results permit us to propose a simple criterion that can help in choosing the plots to be cut where salvage logging is necessary.

The Corsican Nuthatch is a passerine endemic to Corsica island. Its habitat mostly consists in old stands of Corsican pine and locally of Maritime pine. Large fires affected several mountain forests during the summer of 2000. Our objective is to estimate the impact of these fires on Corsican nuthatches population. Among the forest stands occupied by this bird, 848 ha of Corsican pines and 275 ha of Maritime pines were either totally “charred” or simply “browned”. The ranges considered as “charred” amounted to 20.1 % for the Corsican pine and 14.6 % for the Maritime pine. Considering densities measurements obtained from several mapping censuses in unburned forests, we estimate at 25-38 the number of territories eliminated because the stands were completely burned, and at 47-80 the number of territories more or less affected by fire or salvage cutting, the total representing about 4 % of the Corsican nuthatch population. However, data on burnt surfaces did not take into account forest mosaic where nuthatches are able to survive. We then discuss the direct effects of fires on the nuthatches (disappearance from territories owing to the fires itself , or to postfire logging) and the secondary effects (delayed mortality of pines, difficulties for the birds to find new nesting sites and/or to obtain food from the cones during the following winter.)