Large, rather nondescript warbler. Dark with a plain brown back, faintly streaked breast, and pale belly. The tail is rather long and full with a pale-tipped undertail. Usually very shy and hard to spot, other than when singing. Found in dense low bushes often near marshes. The song is a sharp, continuous, and almost machinelike "dzi-dzi-dzi-dzi-dzi-dz."