Bird Conservation International

Research Articles

Distribution and population size of the Corsican Nuthatch Sitta whiteheadi

JEAN-CLAUDE THIBAULTa1 p1 c1, DIDIER HACQUEMANDa2, PASQUALE MONEGLIAa3, HERVÉ PELLEGRINIa2, ROGER PRODONa3, BERNARD RECORBETa4, JEAN-FRANÇOIS SEGUINa5 and PASCAL VILLARDa3

a1 Parc Naturel Régional de Corse, B.P. 417, rue Major Lambroschini, F-20184 Ajaccio cedex..

a2 Office National des Forêts, réseau avifaune, bureau d’étude Environnement-Développement, Pont de l’Orta, avenue de la République, F-20250 Corte, France.

a3 Ecologie et Biogéographie des Vertébrés (Ecole Pratique des Hautes Etudes), UMR 5175, CEFE, 1919 route de Mende, F-34293 Montpellier cedex 5, France.

a4 Direction Régionale de l’Environnement de Corse, BP 334, 19 cours Napoléon, Bâtiment D, F-20180 Ajaccio cedex, France.

a5 Parc Naturel Régional de Corse, B.P. 417, rue Major Lambroschini, F-20184 Ajaccio cedex, France.

Summary

Endemic 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 (= group of connected stands) totalling 185 km2. 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”.

(Received November 13 2009)

(Accepted April 04 2010)

(Online publication March 24 2011)

Correspondence:

c1 Author for correspondence; e-mail: jncldthibault@aol.com

p1 Present address : Muséum National d’Histoire Naturelle, Département Systématique et Evolution, UMR7205 Origine, Structure et Evolution de la Biodiversité, 55 rue Buffon, F-75005 Paris, France.