Migration of black terns Chlidonias niger and common terns Sterna hirundo between south Sweden and the Atlantic coast of Africa
Light-level geolocators were used to record the annual migration cycles of black terns Chlidonias niger (9 individuals, 11 journeys) and common terns Sterna hirundo (7 individuals, 11 journeys) breeding in southernmost Sweden. The black terns used two different non-breeding (Oct–Mar) regions along the Atlantic coast of Africa, either north of the equator between Senegal and Liberia (3 individuals)