A loud, boisterous greenbul that is dark gray-green above and pale below. The back, head, and cheeks are all brownish, but feathers on the head have white centers that give them a distinctly grizzled appearance. The underparts grow plainer and whiter toward the tail, which is long and brown with bright white outer feather tips. Most often found near wet, swampy forest, particularly in areas with Raphia palms. Swamp Greenbul flocks are often located by their cacophonous calls, which consist of a series of notes and cackles that are reminiscent of a recorded human conversation being played too quickly.