Taxonomy:
Crowned Hornbill,
Tockus alboterminatus (Add)Tockus alboterminatus alboterminatus (Add)
Tockus alboterminatus geloensis (Add)
Tockus alboterminatus suahelicus (Add)
Bradfield's Hornbill,
Tockus bradfieldi (Add)Tockus camurus (Add)Von der Decken's Hornbill, Tockus deckeni
Red-billed Hornbill, Tockus erythrorhynchus

Tockus erythrorhynchus damarensis (Add)
Tockus erythrorhynchus degens (Add)
Tockus erythrorhynchus erythrorhynchus (Add)
Tockus erythrorhynchus kempi (Add)
Tockus erythrorhynchus ruahae (Add)
Tockus erythrorhynchus rufirostris (Add)
African Pied Hornbill,
Tockus fasciatus (Add)Tockus fasciatus fasciatus (Add)
Tockus fasciatus semifasciatus (Add)
Northern Yellow-billed Hornbill,
Tockus flavirostris (Add)Tockus hartlaubi (Add)Tockus hartlaubi granti (Add)
Tockus hartlaubi hartlaubi (Add)
Tockus hemprichii (Add)Tockus jacksoni (Add)Southern Yellow-billed Hornbill,
Tockus leucomelas (Add)Tockus leucomelas elegans (Add)
Tockus leucomelas leucomelas (Add)
Tockus leucomelas parvior (Add)
Monteiro's Hornbill,
Tockus monteiri (Add)African Grey Hornbill,
Tockus nasutus (Add)Tockus nasutus dorsalis (Add)
Tockus nasutus epirhinus (Add)
Tockus nasutus forskali (Add)
Tockus nasutus nasutus (Add)
Tockus pallidirostris (Add)Tockus pallidirostris neumanni (Add)
Tockus pallidirostris pallidirostris (Add)