The parasitic jaeger (Stercorarius parasiticus), also known as the Arctic skua, Arctic jaeger or parasitic skua, is a seabird in the skua family Stercorariidae.
Identification is complicated by similarities to long-tailed jaeger and pomarine jaeger, and the existence of three colour morphs. Light-morph adults have a brown back, mainly white underparts and dark primary wing feathers with a white "flash". The head and neck are yellowish-white with a black cap and there is a pointed central tail projection. Dark-morph adults are dark brown, and intermediate-phase birds are dark with somewhat paler underparts, head and neck. All morphs have the white wing flash.
Identification of juveniles is even more problematic, and it is difficult to separate parasitic jaegers from long-tailed jaegers. Parasitic jaegers are bulkier, shorter-winged, and less tern-like than long-tailed jaegers. They are usually warmer toned, with browner shades, rather than grey. However, they show the same wide range of plumage variation. The flight is more falcon-like. The parasitic jaeger is the most common of the three jaeger species seen from shore.
The typical call of these birds is a nasal mewing sound, repeated a few times in display. Their alarm call is a shorter sound.