Oddly shaped warbler with a long, broad tail and a flat-topped head. Watch under the tail for a series of buffy crescents at the tip of each progressively shorter tail feather. Found in thick, wet grassland. Usually very skulky, except when perched out after a rain, or in display flight. Song is a slowly repeated whistle. Dull coloration could make for confusion with other warblers, but the shape is distinctive.