Whiskered Tern

Whiskered Tern (Chlidonias hybrida) is a marsh tern with grey body, black cap, white cheeks and dark red bill 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 field comparisons with similar species in the same habitat (Wikipedia, general species account).

It flies low over freshwater marshes and rice fields, picking insects and small aquatic prey and nesting on floating vegetation. 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).