Ardeola 53(2)

grinoides ranges from the Canary Islands eastwards across some areas of North Africa, the Middle East and some parts of central Asia (Fergusson-Lees and Christie, 2002). It has characteristic plumage patterns and morphometric differences with respect to the rest of peregrine subspecies, but genetic variation is quite low in the peregrinus/pelegrinoides group, and it could be treated as a subspecies of peregrine or even as a well differenced species (Wink et al., 2000). Furthermore, the Canarian breeding falcon present a Barbary phenotype, but haplotipes of F. peregrinus brookei and F. p. pelegrinoides are present according to a preliminary study carried out in Fuerteventura (Amengual et al., 1996). Its typical habitat is noted to be inland deserts and other mainly barren arid areas, but locally in other environments. Limited information has been published on its biology worldwide (Fergusson-Lees and Christie, 2002). Although this falcon is considered as “endangered” (Siverio and Concepción, 2003), its population size has increased and expanded in the Canaries; in 1988 only seven pairs were known in the eastern islands (Hernández et al., 1991) while nowadays around 75 breeding pairs are occupying all the islets and islands (Siverio and Concepción, 2003). Overall in this archipelago, only preliminary aspects of its breeding biology have been studied (Delgado et al., 1999), and what knowledge there is of this species in El Hierro Island is summarized by Martín and Lorenzo (2001). In the present study, the reproduction of Barbary falcons in El Hierro is reported and furthermore, density, distribution pattern of breeding pairs and characteristics of nesting habitat are analyzed and compared with other peregrine population studies. The Canary Islands are a volcanic archipelago which is located 100 km off the north-west African coast (27o37’-29o25’ N and 13o20’18o19’W) and is comprised of seven major islands. El Hierro is situated in the south-west of the archipelago presenting an area of 269 km2 and a maximum altitude of 1,501 m. Its coastline is predominantly rocky with boulder shores and cliffs up to 300 m. The vegetation DENSITY AND BREEDING HABITAT CHARACTERISTICS OF AN INSULAR POPULATION OF BARBARY FALCON FALCO PEREGRINUS PELEGRINOIDES (EL HIERRO, CANARY ISLANDS)