Eastern Marsh Harrier

Eastern Marsh Harrier (Circus spilonotus) is a long-winged harrier with variable brown, black and pale plumage, a facial ruff and a buoyant low hunting flight. 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 quarters reedbeds, marshes and wet grasslands with wings held in a shallow V, dropping onto birds, small mammals, frogs and other prey found below. 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).