Kleptoparasitism by skuas, particularly the great skua, occurs at breeding sites. These predators include fauna such as, seals, arctic terns and arctic skua. The south polar skua ("Stercorarius maccormicki") is a large seabird in the skua family, Stercorariidae. The great skua ("Stercorarius skua") is a large seabird in the skua family Stercorariidae. Small for a skua, the parasitic jaeger measures in length, in wingspan and weighs . Predation by the great skua ("Catharacta skua") is also reduced by several birds arriving simultaneously. The next morning, a large flock of skua attack the trapped Emperor-Land. They received an escort of three Blackburn Skua fighters. The Roc was expected to fly with the Skua. Lucy later also became a fighter ace flying the Skua. The missile was launched at a Denel Skua subsonic target drone near Cape Agulhas. Similar problems occur, of course, with extralimital claims of great skua. Blackburn Skua were lost in the process. The last Skua in service was struck off charge in March 1945.