Forest raptor migration over the Strait of Gibraltar

Abstract

The Strait of Gibraltar is one of the most important places for bird migration in the world. Its location in an important migratory axis known as the Occidental route of the migratory Palearctic-African system and its geographic position between the European and Af- rican continents bearly separated by 14 kilometers of sea turns the Strait into one of the most important “bot- tlenecks” for bird migration through the Mediterranean. Particularly relevant is the mass migration of soaring birds (raptors and storks), with limitations for long-haul flights over the sea for which the Strait constitutes an ob- ligatory pass and an annual concentration point (Bernis, 1980; Zalles & Bildstein, 2000). This relevance of the Gibraltar Strait for bird migration has turned it into one of the areas of the Iberian penin- sula with most ornithological tradition. True reflection of this is the notable ammount of information avail- able in books, articles, and notes currently published. The first exhaustive study about the Strait is due to the works of H.L. Irby who first published his “Ornithology of the Strait of Gibraltar” in 1895. Since then, notable contributions have followed either from the Moroccan side or the Iberian, these being the works of Evans and Lathbury (1973), Bernis (1980) on soaring birds, spe- cially remarkable for their depth and rigor as well as those about non-soaring birds by Tellería (1981), contin- ued with later revisions of general characteristics (case of Finlayson, 1992) or more specific (Fernández-Cruz, 2005; Bensusan et al., 2007).