Northern Red-billed Hornbill (Tockus erythrorhynchus) [XC300773]
by Peter Boesman from Negele - Yabello road, Ethiopia (song)
Northern Red-billed Hornbill (Tockus erythrorhynchus) [XC473964]
by Barry Edmonston from Simbo Beach Resort, Lake Langano, Oromia, Ethiopia (song)
Subspecies
Closest to Monteiro's Hornbill (Tockus monteiri), but also close to Southern Yellow-billed Hornbill (Tockus leucomelas), Eastern Yellow-billed Hornbill (Tockus flavirostris) and Von der Decken's Hornbill (Tockus deckeni), based on similar calls and behaviour, and DNA studies. Subspecies rufirostris and damarensis may be two separate species. Population from southern Mozambique to Natal described as subspecies degens on basis of smaller size, but differences slight; birds of northern Botswana (Ngamiland) formerly separated as subspecies ngamiensis. Yellow-eyed birds from Tanzania, with black circumorbital skin, may represent as yet undescribed subspecies, as also may birds in northern Kenya. Further study is needed.
The following 4 subspecies are recognised:
kempi Tréca & Érard, 2000 - Southern Mauritania and Senegambia east to Inner Niger Delta. Considered by some authors to be a distinct species, Western Red-billed Hornbill (Tockus kempi).
erythrorhynchus (Temminck, 1823) - Inner Niger Delta east to Ethiopia and Somalia, south to Tanzania.
rufirostris (Sundevall, 1851) - Southern Angola and northern Namibia east to Zambia and southern Malawi and south to north-eastern South Africa. Considered by some authors to be a distinct species, Southern Red-billed Hornbill (Tockus rufirostris).
damarensis (Shelley, 1888) - North-western and central Namibia. Considered by some authors to be a distinct species, Damara Hornbill (Tockus damarensis).
BirdLife International Species Factsheet