An unusual and distinctive warbler of humid forest, mostly olive-brown with a whitish eyebrow and throat. Found in rainforest at low and middle elevations, usually at middle levels. Somewhat similar to Uganda Woodland-Warbler, but larger, with darker underparts. Also distinguished from other similar warblers by the dark underparts. Most readily detected by its distinctive and frequent call, a penetrating double whistle. Also gives a fast, scolding chatter.