Pomarine Jaeger

Pomarine Jaeger (Stercorarius pomarinus) is a powerful seabird with broad wings, a heavy bill and spoon-shaped central tail feathers in breeding adults. Body shape, bill structure, plumage pattern and voice provide the strongest field characters. Age, sex and season may alter its appearance, so identification should combine several features and careful direct field comparisons with similar species in the same habitat (Wikipedia, general species account).

It breeds on Arctic tundra, eats lemmings and eggs there, and chases seabirds for food during oceanic migration. Its movements and social behaviour vary through the year, with breeding birds generally more dispersed and non-breeding birds gathering where food is concentrated. Japanese records place it within the country's documented avifauna as a resident, migrant or visitor (Wikipedia, general species account; Wildlife of Japan occurrence records).