Middendorff's Grasshopper Warbler

Middendorff's Grasshopper Warbler (Locustella ochotensis) is a medium brown grasshopper warbler with a pale eyebrow, subtly streaked back and a long rounded tail. 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 breeds from eastern Siberia through Kamchatka and the northern Kurils to northern East Asia, occupies dense coastal grass and scrub and migrates to the Philippines, Borneo and Sulawesi. 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).