Analysis of the Spatial Migration Patterns of Adult Honey Buzzards (Pernis apivorus) During Spring and Autumn in the Central Mediterranean
In this paper we analyse the spatial migration patterns and the water crossing tendency of adult Honey Buzzards during spring and autumn migration in the Central Mediterranean region. In this area, during spring, these long-distance migrants wintering in western-central Equatorial Africa, concentrate crossing the sea between Africa and Europe through the Channel of Sicily, about 150 km wide, at least part of them via the islands of Pantelleria and Marettimo. When they reach western Sicily most of them fly east, along the mountain chain of northern Sicily, towards the Strait of Messina. Nevertheless, thousands of birds use a more direct route to reach the continental mainland undertaking the crossing of the Tyrrhenian Sea via Ustica and the Lipari Islands. During autumn the migration of adult Honey Buzzards is less consistent. They tend to follow the Italian Peninsula and northern Sicily reaching Africa through the Channel of Sicily while very few cross the Tyrrhenian Sea. On the contrary, during their first migration, large numbers of juveniles, moving about two weeks later than adults, cross the Central Mediterranean region on a broader front presumably along NE-SW innate axis. It is supposed that larger numbers of adult Honey Buzzards choose the central Mediterranean route during spring migration to reach earlier their breeding areas in eastcentral Europe. During post-reproductive movements most of them would circumfly the Mediterranean Sea crossing at the Strait of Gibraltar and at the Bosporus. In this picture the discovery of more direct routes between breeding and wintering areas made by juvenile birds during their first migration may have the adaptive value.