The former Red-billed Hornbill (Tockus erythrorhynchus) has undergone a five-way split as follows:
*Northern Red-billed Hornbill (Tockus erythrorhynchus)
*Damara Red-billed Hornbill (Tockus damarensis)
*Southern Red-billed Hornbill (Tockus rufirostris)
*Tanzanian Red-billed Hornbill (Tockus ruahae) - new taxon
*Western Red-billed Hornbill (Tockus kempi) - new taxon
Here in the dry savannah of southwest Africa, we have the Damara Red-billed Hornbill characterized by a white face, brown eye, and pink facial skin. It is a Namibia near endemic with a small population in adjacent Angola.
Reference: Kemp, A.C. and W. Delport. 2002. Comments on the status of subspecies in the red-billed hornbill (Tockus erythrorhynchus) complex (Aves: Bucerotidae), with the description of a new taxon endemic to Tanzania. Annals of the Transvaal Museum 39: 1-8. Online at:
https://www.coraciiformestag.com/Research/Hornbill/red-billed%20hornbill.pdf