The relationships between this species and the Buff-rumped Warbler (Phaeothlypis fulvicauda) remain to be fully elucidated. In the past some authorities have considered them to be conspecifics, or to be better placed in the genus Basileuterus, the Riverbank Warbler’s disjunct distribution remains intriguing. It inhabits lowland forest and edges, always along streams or in swampy areas, in northeast South America south to central-southern Amazonia, with separate populations in the Atlantic Forest of southeast Brazil, eastern Paraguay, and northeast Argentina, and finally in the east Andean foothills of Bolivia. Each of these populations is represented by a separate subspecies, of which those in Amazonia and the Atlantic Forest are definitely sister taxa according to recently published molecular data. The species’ loud, reverberating song, and habit of coming out to feed in open on tracks and even roads, makes it easily observed.