First GPS-tracking of Cory's shearwater in the Mediterranean Sea

The behaviour and ecology of seabirds such as albatrosses, petrels and shearwaters have been the subject of numerous studies, often employing the most recent technologies to track birds during their foraging trips. Until now, however, large oceanic species have been preferred for tracking studies because of the dimensions and weight of the devices available. New light-weight GPS (Global Positioning System) loggers (< 9 g) were used to track foraging trips of a medium-sized species, the Cory's shearwater, for the first time in the Mediterranean Sea. The tracks obtained showed that Mediterranean Cory's shearwaters alternatively used one of two different fishing areas. Various explanations could account for this difference; one of these could be that the two directions have a different relevance for the birds, being for chick- and self-provisioning. This study provides new hypotheses concerning the behaviour of Cory's shearwaters in the Mediterranean Sea, a different environment compared to previously studied oceans.