Migration strategies in relation to the population of origin: The caseof Cory's Shearwaters tracked by GLS

摘要

Migration routes and wintering areas of seabirds are generally poorly known, particularly in relation to the population of origin, probably due to the difficulty in recovering rings from open sea. Using light level geolocators (GLS), we tracked migration movements over one year of 22 Cory's Shearwaters Calonectris diomedea, breeding in three different areas: Mediterranean (7), Canary Is. (7) and Azores Is. (8). Most birds clearly migrated following the south, and to a lesser extent, north Atlantic gyres. Wintering grounds of most birds were clearly associated to major coastal upwelling regions, but important differences were found in relation to the population of origin. Most Mediterranean birds C. d. diomedea spent the winter associated to the Canary current. In contrast, most Canary and Azorean birds C. d. borealis spent the winter associated to the Benguela and Agulhas currents, but some birds spent the winter associated to the Brazilian current.