Great Knot

Great Knot (Calidris tenuirostris) is a large, heavy-billed sandpiper with black-spotted breast and chestnut scapulars in breeding plumage. 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 comparisons with similar species in the same habitat (Wikipedia, general species account).

It breeds in northeastern Siberian mountains and migrates to tidal flats where dense flocks probe for molluscs and worms. 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).