Phylloscopus borealoides
Family: Leaf Warblers · Status: Rare migrant · Size: 11.5 cm · Conservation: Least Concern
Breeds across the Japanese Archipelago, Sakhalin and Kuril Islands, wintering to Southeast Asia.
Resembles Arctic Warbler but has a dark greyish crown contrasting with olive-greenish mantle, warmish olive-brown rump and pale greyish-pink legs and feet. Visually indistinguishable from Pale-legged Leaf Warbler; separable in the field only by call (~5 kHz vs ~6 kHz) or song.
Forest.
Forages for insects on the forest floor; also climbs low shrubs and vines, and occurs in the mid-storey to canopy.