Small, compact brown warbler with distinct black streaking all over the body. Note evenly spaced narrow pale fringes to the tertials in adults and juveniles. Very hard to see when not singing, but when located can be very confiding. Breeds in swampy open forests, reedbeds, and swampy edges across the taiga; winters in similarly tangled and densely vegetated habitat. Song is a continuous and insectlike reeling, similar to Common Grasshopper Warbler.