Small, compact brown warbler. Shorter-tailed than Common Grasshopper-Warbler with distinctive streaking on the breast in adults. Note evenly spaced narrow pale fringes to the tertials in adults and juveniles. Very hard to see when not singing, but when found can be very confiding. Breeds in swampy open forests across the taiga. Song is a continuous and insectlike reeling, similar to Common Grasshopper Warbler.