Snake richness predicts breeding distribution of short-toed snake eagle in central Italy.
Birds of prey, as top predators, play a key role in ecosystem functioning by regulating prey populations and, by means of cascade effects, promoting biodiversity. This makes them adequate sentinels of ecosystem health. Here we analyse the relationship between the occurrence of breeding short-toed snake eagle (Circaetus gallicus) and both the richness of potential prey species and landscape characteristics by taking into account two different spatial scales (i.e. nest-site scale and landscape scale). The short-toed snake eagle offers an interesting case study for investigating the relationships between top predators, prey diversity, and habitats, because it is an extremely specialised raptor…
Spring raptor migration at Ustica, southern Italy
The island of Ustica, lying at 38°42’N 13°12’E in the Tyrrhenian Sea, is approximately 60 km north of western Sicily and 270 km northeast of the Cap Bon promontory in Tunisia (fig.1). Although covering an area of only 7,600 ha, its isolation makes it attractive to migrant birds. In order to establish the importance of Ustica for the spring migration of raptors in the Mediterranean basin, counts of migrating raptors were made from the highest point of the Falconiera promontory, which dominates the northeast coast of the island, between 22nd March and 20th May 2002.Each spring, thousands of raptors cross the Mediterranean Sea between Africa and southern Italy during their northward migration …
Long-term changes in autumn migration dates at the Strait of Gibraltar reflect population trends of soaring birds
A growing body of work shows that climate change is the cause of a number of directional shifts in the spring phenology of migratory birds. However, changes in autumn phenology are well studied and their consistency across species, as well as their link with population trends, remains uncertain. We investigate changes in the autumn migration dates of 11 species of soaring birds over the Strait of Gibraltar over a 16-year period. Using models corrected for phylogeny, we assessed whether ecological and morphological characteristics, as well as population trends, account for interspecific shifts in migration times. We recorded different phenological changes in different periods of the migratio…