The skuas and jaegers (family Stercorariidae) are a family of birds belonging to the order Charadriiformes, often regarded as shorebirds. These pelagic birds breed in the high Arctic and Antarctic tundra but spend most of the year offshore in the ocean, often on the opposite side of the globe. They are avid hunters and scavengers, often foraging in seabird and sea lion colonies. These birds are kleptoparasitic, skillfully stealing food from other seabirds — often gulls and even gannets, on the wing.
The family comprises 7 species belonging to the genus Stercorarius, which includes two different types of species. Jaegers (3 species) are smaller in size and have light-colored morphs and elaborated tails, and all breed in the Northern Hemisphere. Skuas (4 species) are large birds with overall dark plumages, and all but one species breed in the Southern Hemisphere. Despite their breeding grounds, all members of the family but one skua regularly forage in the oceanic waters of the opposite hemisphere during non-breeding period.
Dark morph in Vardøya, Varanger Peninsula, Norway, 3 Jun 2023
Parasitic jaeger
Stercorarius parasiticus
Breeds in shores of the Northern Hemisphere south to the Hudson Bay and the Baltic Sea and concentrates in the nutrient-rich waters around southern South America, South Africa, Australia and New Zealand. Adults of light and dark morph occur at apparently similar rates. I have the species at its breeding grounds in summer in Lapland and in migration in the Atlantic from Galicia (N Spain) and the Mediterranean around Castellón (Valencian Community, E Spain).
Kongsfjordfjellet, Varanger Peninsula, Norway, 3 Jun 2023
Long-tailed jaeger
Stercorarius longicaudus
Breeds in the tundra from the highlands of Scandinavia, where the nominate form occurs, through Siberia to the Canadian High Arctic, where the pallescens form occurs. It is the only jaeger without a dark morph yet known for adults, which sport long tail streamers. I have encountered the species at breeding site in Lapland and at sea in Galicia (N Spain).
Light morph in Vardøya, Varanger Peninsula, Norway, 16 May 2024
Pomarine jaeger
Stercorarius pomarinus
Breeds in the tundra of Siberian and Canadian high Arctic, but spends the non-breeding period in the pelagic zone of all oceans, often in tropical latitudes unlike other jaegers. Adults have a spoon-shaped tail and two morphs. Despite being classified as a jaeger, is it more closely related to the skuas. I have seen this species at sea in Lapland, in Galicia (N Spain) and in the Gibraltar Strait (S Spain).
Estaca de Bares, A Coruña, Galicia, Spain, 20 Aug 2025
Great skua
Stercorarius skua
Breeds near seabird colonies on islets and cliff lanes off the British Isles (where often known as ‘bonxie‘), Faroes, Iceland, Norway and Svalbard, being the only skua breeding in the Northern Hemisphere. Foraging grounds include the Atlantic Ocean and the west Mediterranean Sea. I have observed this species in Galicia (N Spain).
