Small songbird, essentially identical in plumage to Arctic Warbler and Japanese Leaf Warbler. A late spring migrant, often moving up the Chinese coast from Southeast Asia in mid- to late May. Breeds in the taiga forests and forest edges of the Kamchatka peninsula, Hokkaido, Sakhalin, and the Kuril Islands. Call is a low “chuck,” averaging lower than that of Japanese Leaf and Arctic Warblers. Song is a broken series of chattering notes, with each segment being in more discrete phrases than the more consistent, higher-pitched song of Arctic.