They tend to be heavier in winter and particularly at the start of their migration.They have olive-brown upperparts and white underparts heavily streaked with black; the flanks have an olive hue. A white ring surrounds the eyes, and a black stripe runs below the cheek. They have a line of orange feathers with olive-green tips running along the top of their head, bordered on each side with blackish-brown. The orange feathers can be erected to form a small crest. The eyes and the upper part of the thin pointed beak are dark, while the lower beak is horn-colored and the legs and feet are pinkish.
Males and females look alike. Immature birds have tawny fringes to the tertiary remiges and sometimes buff-tipped outer primary wing coverts. Most conspicuously, the olive-green tips of the crown feathers, which are hardly visible in adult birds, are far larger in extent in immatures and cover the orange crown-stripe almost or completely.
