Abstract
There are considered to be ninespecies in the genus Poicepbalus which has been divided into two groups, namely the P. robustus;superspecies with two species and the P. meyeri superspecies with seven species. The two P. robustus species, namely P. robustus and P. gulielmi, are similar in size and plumage characteristics. P. robustus can be divided into three isolated populations which differ at the subspecific level; the head is brownish in the mostsoutherly form, P.r. robustus, which is restricted to the southern part of Africa, and silvery grey in the remaining two forms, P.r. juscicollis in westAfrica and P.r. suabelicus in southcentral Africa. The plumage colour variation is paralleled by a habitat difference: P.r. juscicollis and P.r. suabelicus inhabit woodland and wooded savannah mainly in the tropical regions, while P. r. robustusmainly inhabits montane forest in subtropical and temperate regions, where it breeds. The montane evergreenforest is associated with the foothills of the Great Escarpment of southern Africa