Dull brown reed warbler with a sharply marked head, found in a variety of wetland habitats with substantial vegetation cover. Namesake black brow line is not always apparent, but the thick and strikingly pale supercilium is distinctive in its clean-cut and squared-off appearance. Somewhat similar to the rarer Streaked Reed Warbler, but averages much darker and lacks the latter's black striping on the back and wings. Song is a scrambled set of chatters, chirps, and rattles, more musical and tuneful than Oriental Reed Warbler. Gives dry “chit,” often in series.