Arctic Skua vs Great Skua

The Arctic Skua (Stercorarius parasiticus) and Great Skua (Stercorarius skua) can be distinguished primarily by size and structure. The Great Skua is significantly larger and bulkier, while the Arctic Skua is more slender with pointed wings and a longer tail. Both species exhibit plumage variation, but the Great Skua is generally more uniform in coloration.

1. Size and Bulk: Great Skuas are noticeably larger and bulkier. 2. Tail Shape: Arctic Skuas have pointed tails, especially visible in flight. 3. Plumage: Look for the contrasting morphs in Arctic Skuas. 4. Behavior: Observe for kleptoparasitic behavior in Arctic Skuas. 5. Habitat: Consider the environment; Great Skuas are more coastal.

The Great Skua is much larger and more robust compared to the smaller, more agile Arctic Skua.

Arctic Skuas have two morphs, dark and light, with intermediate forms, while Great Skuas are more consistently brown with less variation. Arctic Skuas have a more contrasting plumage with a darker cap and paler underparts in light morphs.

Arctic Skuas are known for their agile flight and kleptoparasitic behavior, often chasing other seabirds to steal food. Great Skuas are more aggressive and may hunt and kill other birds.

Both species are found in northern latitudes but the Arctic Skua is more likely to be seen in open ocean environments, while the Great Skua is often found in coastal areas and islands.

Vocalizations are not a primary distinguishing feature in the field for these species.