Spatio-temporal variation in the diet of Cory's shearwater Calonectris diomedea in the Azores archipelago, northeast Atlantic

► The diet of Cory's shearwater was studied in the Azores over four breeding seasons, using stomach flushings from 959 birds. ► Over 70 taxa were found in the diet, trebling what was previously known. ► Blue jack mackerel was the main prey of Cory's shearwaters in 2002 but was absent from the diet in 1999 and 2000. ► Thirty-seven species of oceanic cephalopods were present including three octopods. ► Eighty-three percent of the cephalopod species caught have photophores and could be targeted at dusk and dawn.