Ruff

Ruff (Calidris pugnax) is a strongly dimorphic sandpiper whose males develop extravagant neck ruffs and head tufts in highly variable colours. 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 feeds on insects, worms and seeds in wet grasslands and mudflats and males gather at communal display leks. 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).