Southern red-billed hornbill
The southern red-billed hornbill is a species of hornbill in the family Bucerotidae, which is native to the savannas and dryer bushlands of southern Africa. It is replaced by a near-relative, the Damara red-billed hornbill, in the arid woodlands of western Namibia. All five red-billed hornbills were formerly considered conspecific.
Subspecies
It is usually treated as a monotypic taxon, but two additional subspecies have been proposed:Tockus rufirostris rufirostris Sundevall, 1850 — bushveld regions of Transvaal, southern Botswana and southern Zimbabwe Tockus rufirostris degens Clancey, 1964 — eastern lowveldTockus rufirostris ngamiensis Roberts, 1932 — northern Namibia to northern ZimbabweT. r. degens is the smallest in size, while T. r. ngamiensis has browner plumage and a more distinct tail bar. The differences are clinal.
Description
[file:ZA-KNP-toko.jpg|left|thumb|Immature bird – T. r. rufirostris]The sexes are similar, but males are larger and heavier. Males also have somewhat longer bills, with the lower mandible coloured black to a variable extent. It is distinguishable from other red-billed hornbills by the combination of yellow iris and pale orbital skin, and the ample blackish plumage streaking from the ear coverts to the side of the neck. The throat is white, and the wing coverts clearly spotted.