On the morning of 18 February 2011, I observed a multi-species feeding flock at Second Lagoon (26°41'S 15°08'E) near the southern Namibian coastal town of Lüderitz. The flock, composed of several hundreds of Cape Cormorants Phalacrocorax capensis, dozens of Hartlaub's Gulls Larus hartlaubii and Swift Terns Sterna bergii, as well as some White-breasted Cormorants P. lucidus, Kelp Gulls L. dominicanus and Sandwich Terns S. sandvicensis, was feeding on a shoal of small fish and the birds were herding it towards the southern edge of the lagoon. While watching this large flock, I noticed a smaller group of birds, composed of 24 Hartlaub's Gulls, two Kelp Gulls, 31 Swift Terns and two Sandwich Terns approximately 300 m north of the main flock and at a distance of about 400 m from me. The group was hovering above an adult Kelp Gull sitting on the water that was seemingly attempting to control a large fish. However, a closer look revealed that the Kelp Gull was in fact attacking a Sandwich Tern, gripping its head and/or neck with its beak and forcing the struggling tern's head under water.