Factors influencing the distribution, abundance and nest-site selection of an endangered Egyptian vulture (Neophron percnopterus) population in Sicily INTRODUCTION The Egyptian vulture (Neophron percnopterus) is a medium-size scavenging bird with a wingspan of 163–171 cm (Forsman, 1999). It feeds on small vertebrate and domestic livestock, but can also prey upon small animals. Most of the European population is concentrated on hilly or mountainous dry, open Mediterranean landscape, generally below 1800 m above sea level, where it nests on cliffs. Under optimal conditions, it seems limited only by breeding cliff availability (Donázar, Ceballos & Leon, 1989). Many European birds winter in sub-Saharan Africa within the 14°–17°N belt (Thiollay, 1989). The species is endangered in its Palaearctic range and is classified in category 3 according to the Species of European Conservation Concern (Del Hoyo, Elliot & Sargatal, 1994; Donázar, 1997; Heath, Borggreve & Peet, 2001) because the populations, with a dramatic decrease of some 50% (i.e., 900–1500 pairs) from 1984 to 1994, have declined or are extinct in many North African and European countries (Levy, 1996). The Italian population, which is ‘critically endangered’ (Bulgarini et al., 1998), is found in the central and southern Apennines and in Sicily (Liberatori & Massa, 1992; Liberatori & Penteriani, 2001). The current Sicilian population lives only in the western part of the island, nesting in areas between 400 and 1000 m above sea level (Seminara, 1985; Lo Valvo, Massa & Sarà, 1993). It experienced a sharp decline from some 30 pairs in 1970–80 (Iapichino & Massa, 1989), to three pairs in 1997. Since 2000, however, the population has increased to 10–13 pairs. Although varying throughout Europe, the factors leading to the decline are all due to human activity. The top-ranked causes include killing, nest robbery and poisoning, followed by land-cover change and modification in traditional livestock-breeding practices (Grubaè, 1989; Elosegi, 1989; Donázar, 1993; Liberatori & Massa, 1992; Levy, 1996; Abuladze & Shergalin, 1998; Liberatori & Penteriani, 2001). Habitat quality is involved in the regulation of the raptor populations and determines the species’ settlement pattern (Newton, 1998). Investigation of the habitat requirements of endangered species is crucial to many aspects of conservation (Manly, McDonald & Thomas, 1993; Noss, O’Connell & Murphy, 1997). Several raptors, such as the Egyptian vulture, show pronounced philopatry and site-fidelity (Newton, 1979). It seems essential, therefore to explore the factors limiting the population density as well as to describe its habitat quantitatively. Maurizio Sarà 1 and Massimiliano Di Vittorio 2 1 Department of Animal Biology, Via Archirafi, 18–90123 Palermo, Italy 2 ALTURA, Via M. Jevolella, 2 – Termini Imerese, Italy (First received 17 July 2002; resubmitted 24 March 2003; accepted 29 April 2003) Abstract The Egyptian vulture (Neophron percnopterus) breeds in Sicily and, in 22 years of monitoring, has shown a decline followed by a slight recovery. We used Generalised Linear Models to predict: (1) the distribution range, (2) the habitat selection within the range, (3) the quality (i.e., occupation rate, breeding success) of breeding sites. Some 60% of Sicily proved to be unsuitable, being either too densely forested and without cliffs for nesting, or too densely populated, along with intensive agriculture. The models converged, indicating that the pairs select a precise upland habitat where low cliffs, distant from urban areas, are surrounded by arboreal crops and Mediterranean vegetation. The variables predicting the quality of a site are also related to human disturbance, including the distance from a road or the presence of heavy traffic. Natural restocking, in the last 3 years, is occurring in quiet sites and in proximity to extensive grazing land rich in sheep and goat herds. These results focused on short-term programmes for local management of the species aimed at protracting the natural restocking: namely, the activation of (1) a stable system of artificial feeding stations, (2) nest site protection with joint activities for increasing public awareness, (3) a reintroduction project, by hacking, of juveniles born in captivity in Italian and European breeding centres. All correspondence to: Maurizio Sarà. Tel: 0039–(0)91–6230117; Fax: 0039–091–6230144; E-mail: mausar@unipa.it. Animal Conservation (2003) 6, 0–000 © 2003 The Zoological Society of London DOI:10.1017/S1367943002004000 Printed in the United Kingdom