Tiny, compact, dark bittern. Slate-gray on the upperparts and pale on the underparts, which have thick dark streaks. Found in heavily vegetated wetland habitats, including ponds, swamps, and sometimes mangroves. Uncommon, shy, and secretive. Call is a short series of low “hraw” notes. Somewhat similar to Striated Heron, but smaller, shorter- and thicker-necked, and darker on the back. 

Source : ebird.org

A small secretive heron; climbs about in papyrus and tall marsh vegetation. When disturbed , it may freeze motionless, with out-stretched neck and bill poiting  upward.

Source : Helm field guides / Birds of Kenya & Northern Tanzania