
Photo: Dr. Raju Kasambe · CC BY-SA 4.0 (May be cropped or resized)
Calidris tenuirostris
Rare visitor: recorded only occasionally in this country
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. The Korean vertebrate catalogue used for this guide records the species in South Korea (Wikipedia, general species account; Wildlife of Korea occurrence records).