Description wikipedia

The black-backed puffback (Dryoscopus cubla) is a species of passerine bird in the family Malaconotidae. They are common to fairly common sedentary bushshrikes in various wooded habitats in Africa south of the equator. They restlessly move about singly, in pairs or family groups, and generally frequent tree canopies. Like others of its genus, the males puff out the loose rump and lower back feathers in display, to assume a remarkable ball-like appearance. They draw attention to themselves by their varied repertoire of whistling, clicking and rasping sounds. Their specific name cubla, originated with Francois Levaillant, who derived it from a native southern African name, where the "c" is an onomatopoeic click sound. None of the other five puffback species occur in southern Africa.