Birds of Singapore
by the Bird Society of Singapore
Stercorarius parasiticus
Family: Jaegers and Skuas · Status: Rare migrant · Size: 42–54.5 cm · Conservation: Least Concern
Breeds in the Arctic, across the coasts of North America including Greenland, and across Russia. Outside breeding season, winters in tropical seas and temperate oceans in the Southern Hemisphere, including the Southern Cone of South America, Southern Africa, and Australia.
Also known as the Arctic Skua, this is a medium sized Jaeger, smaller and slimmer than Pomarine Jaeger, lacking the heavy, barrel-chested build of that species. Can occur in light and dark colour morphs. On the breeding plumage of the light morph, the face and cap are black, upperparts are dark brown/grey except for a pale yellow band wrapping around the nape to the sides of head. Underparts are white except for a brown breast band (sometimes indistinct) and a dark vent. The rarer dark morph simply appears grey or brown all over. Breeding adults have elongated central tail feathers extending beyond the other rectrices, but these elongated feathers are not twisted as in Pomarine Jaeger. Non-breeding adults and immatures become barred all over, but the extent of barring may vary. Parasitic Jaeger shows prominent white at the bases of the primaries on the underwing appearing as a broad single white panel, but lacks this white panel on the upperwing. The outer 4-6 primaries on the upperwing show prominently white shafts, fewer than Pomarine Jaeger.
Open seas
A pelagic species that kleptoparasitises terns and other seabirds, snatching food in aerial pursuit. Typically silent when chasing prey.