Neil Aldridge / Southern yellow-billed hornbill (Tockus leucomelas) displays while calling in winter, Kruger National Park, South Africa.

John Waters / Southern Yellow billed Hornbill {Tockus leucomelas} Kalahari Desert, Northern Cape, South Africa

Andrew Parkinson / Yellow billed hornbill {Tockus flavirostris} Etosha NP, Namibia

Staffan Widstrand / Southern Yellow-billed Hornbill, (Tockus leucomelas) tossing a fly larva at a carrion site, Zimanga Private Nature Reserve, KwaZulu Natal, South Africa

Staffan Widstrand / Southern Yellow-billed Hornbill, (Tockus leucomelas), eating fly larvae at a carrion site, Zimanga Private Nature Reserve, KwaZulu Natal, South Africa

Suzi Eszterhas / Yellow-billed hornbill (Tockus flavirostris) perched in tree with food in beak. Sabi Sands Game Reserve, South Africa.

Lucas Bustamante / Southern yellow billed hornbill (Tockus leucomelas) perched on branch, Etosha National Park, Harare Province, Namibia.

Juergen & Christine Sohns / Southern Yellow-billed Hornbill (Tockus leucomelas) flying, Kruger National Park, South Africa

Juergen & Christine Sohns / Southern Yellow-billed Hornbill (Tockus leucomelas) hunting flying insect, Kruger National Park, South Africa

Lucas Bustamante / Southern yellow-billed hornbill (Tockus leucomelas) on ground, Moremi Game Reserve, Botswana.

Francois Savigny / Southern yellowbilled hornbill {Tockus leucomelas} perching on branch with beak open, Kruger NP, South Africa

Jen Guyton / Southern yellow-billed hornbill (Tockus leucomelas) in Kruger National Park, South Africa.

Jen Guyton / Southern yellow-billed hornbills (Tockus leucomelas) guarding their nest hole in a tree, Kruger National Park, South Africa.

Loic Poidevin / Southern yellow billed hornbill (Tockus leucomelas) male in tree, Kenya

Ann & Steve Toon / Southern yellowbilled hornbills (Tockus leucomelas) courtship display. Kruger National Park, South Africa. September.

Richard Du Toit / Eastern Yellow-billed Hornbill (Tockus flavirostris) pair, Kruger National Park, South Africa

Yva Momatiuk & John Eastcott / Southern Yellow-billed Hornbill (Tockus leucomelas), Kruger National Park, South Africa

Wim van den Heever / Southern Yellow-Billed Hornbill (Tockus leucomelas) yawning while sitting on the ground, Sabi Sand Game Reserve, South Africa

Neil Aldridge / Southern yellow-billed hornbill (Tockus leucomelas) perched on a broken branch, Kruger National Park, South Africa.

Neil Aldridge / Portrait of a Southern yellow-billed hornbill (Tockus leucomelas) in early morning. Kruger National Park, South Africa.

Neil Aldridge / Portrait of a Southern yellow-billed hornbill (Tockus leucomelas) in woodland, Kruger National Park, South Africa.

Neil Aldridge / Southern yellow-billed hornbill (Tockus leucomelas) searching for food in leaf litter, Kruger National Park, South Africa.

Neil Aldridge / Southern yellow-billed hornbill (Tockus leucomelas) displays while calling in winter, Kruger National Park, South Africa.

Richard Du Toit / Yellow-billed hornbill (Tockus flavirostrus) in flight, Kruger National Park, South Africa.

Richard Du Toit / Eastern Yellow-billed Hornbill (Tockus flavirostris), Kruger National Park, South Africa

Sean Crane / Southern Yellow-billed Hornbill (Tockus leucomelas), Central Kalahari Game Reserve, Botswana

Sean Crane / Southern Yellow-billed Hornbill (Tockus leucomelas), Okavango Delta, Botswana

Sean Crane / Southern Yellow-billed Hornbill (Tockus leucomelas) looking at camera, Kalahari Game Reserve, Botswana

Christine Jung / Southern Yellow-billed Hornbill (Tockus leucomelas), Kgalagadi Transfrontier Park, Northern Cape, South Africa

Ralph Martin / Southern Yellow-billed Hornbill (Tockus leucomelas), Namibia

Denis-Huot / Yellow-billed hornbill (Tockus flavirostris) Kruger National Park, South Africa

Richard Du Toit / Yellow-billed Hornbill (Tockus flavirostrus) portrait, Kgalagadi Transfrontier Park, Botswana

Chien Lee / Southern Yellow-billed Hornbill (Tockus leucomelas), Khama Rhino Sanctuary, Botswana

Chien Lee / Southern Yellow-billed Hornbill (Tockus leucomelas), Kruger National Park, South Africa

Martin Willis / Southern Yellow-billed Hornbill (Tockus leucomelas), Kruger National Park, South Africa

Christophe Courteau / Portrait of a Southern yellow billed hornbill {Tockus leucomelas}, Okavango Delta, Botswana.

Brent Stephenson / Southern Yellow-billed Hornbill (Tockus leucomelas) perched in a shrub in evening light. Kruger National Park, South Africa, January.

Chris Gomersall / Male Southern yellow billed hornbill (Tockus leucomelas) perched in acacia tree, Etosha National Park, Namibia, November

Tim Laman / Southern yellow-billed hornbill (Tockus leucomelas) perched on rock, with Impala in background. Kruger National Park, South Africa.

Tim Laman / Southern yellow-billed hornbill (Tockus leucomelas) perched on thorn bush. Kruger National Park, South Africa.

Jouan & Rius / Southern Yellow billed Hornbill (Tockus leucomelas) Etosha NP, Namibia

John Waters / Southern Yellow-billed Hornbill {Tockus leucomelas} Kalahari Desert, Northern Cape, South Africa

Richard Du Toit / Southern Yellow-billed Hornbill (Tockus leucomelas) portrait, Savuti, Chobe National Park, Botswana

Gabriel Rojo / Southern yellow billed hornbill {Tockus leucomelas} Kruger National Park, South africa

Gabriel Rojo / Southern yellow billed hornbill {Tockus leucomelas} Kruger National Park, South Africa

Gabriel Rojo / Southern yellow billed hornbill {Tockus leucomelas} preening, Kruger National Park, South Africa

Gabriel Rojo / Southern yellow billed hornbill {Tockus leucomelas} Kruger National Park, South africa

Gabriel Rojo / Southern yellow billed hornbill {Tockus leucomelas} preening, Kruger National Park, South Africa

Gabriel Rojo / Southern yellow billed hornbill {Tockus leucomelas} preening, Kruger National Park, South Africa

Gabriel Rojo / Southern yellow billed hornbill {Tockus leucomelas} preening, Kruger National Park, South Africa

Gabriel Rojo / Southern yellow billed hornbill {Tockus leucomelas} preening, Kruger National Park, South Africa

David Shale / Southern yellow billed hornbill {Tockus leucomelas} Kruger NP, South Africa

Pete Oxford / Yellow Billed Hornbill {Tockus flavirostris} Moremi Wildlife Reserve Okavango, Botswana.

Tony Heald / Yellow billed hornbill feeds on fruit (Tockus flavirostris) Etosha NP Namibia

Andrew Parkinson / Yellow billed hornbill {Tockus flavirostris} Etosha NP, Namibia

Richard Du Toit / Eastern Yellow-billed Hornbill (Tockus flavirostris) adult arriving at nest hole with food for young, summer, Chobe National Park, Botswana

Richard Du Toit / Yellow billed hornbill flying to nest hole {Tockus flavirostris} Botswana

Richard Du Toit / Yellow billed hornbill {Tockus flavirostris}profile portrait, Malamala GR, South Africa

Richard Du Toit / Yellow billed hornbill display {Tockus flavirostris} Moremi WR, Botswana

Paul Hobson / Southern yellow billed hornbill {Tockus leucomelas} Namibia

Richard Du Toit / Yellow billed hornbill {Tockus flavirostris} Etosha NP, Namibia.

Richard Du Toit / Yellow billed hornbills {Tockus flavirostris} Etosha NP, Namibia.

Richard Du Toit / Yellow billed hornbill (Tockus flavirostris) Botswana Moremi WR.

Richard Du Toit / Yellow billed hornbill (Tockus flavirostris. Moremi reserve, Botswana, Southern Africa

Tony Heald / Yellow billed hornbill {Tockus flavirostris} Moremi WR, Botswana, Africa

Juergen & Christine Sohns / Southern Yellow-billed Hornbill (Tockus leucomelas), Kruger National Park, South Africa

Gerald Haas/ BIA / Southern Yellow-billed Hornbill (Tockus leucomelas), Moremi Game Reserve, Botswana

Francois Savigny / Southern yellow billed hornbill {Tockus leucomelas} Kruger NP South Africa

Wild Shots Outreach / Southern yellow-billed hornbill (Tockus leucomelas) in tree, Kruger National Park. South Africa. Picture taken by pupil Chris Mojela during Wild Shots Outreach Residential Course.

Richard Du Toit / Eastern Yellow-billed Hornbill (Tockus flavirostris) pair, Mapungubwe National Park, South Africa

Chien Lee / Southern Yellow-billed Hornbill (Tockus leucomelas) calling, Kruger National Park, South Africa

Onne van der Wal / Southern yellow-billed hornbill (Tockus leucomelas) perched on tree branch, Motswari private game reserve, northern South Africa.

Richard Du Toit / Southern Yellow-billed Hornbill (Tockus leucomelas) feeding on insect, Limpopo, South Africa

Andrew Parkinson / Yellow billed hornbill {Tockus flavirostris} Kgalagadi TFP S Africa Transfrontier

Eric Baccega / Southern yellow-billed hornbill (Tockus leucomelas) perched on branch, Okavango Delta, Botswana, Africa.

Guy Edwardes / Southern yellow-billed hornbill (Tockus leucomelas) in flight. Savuti, Botswana.

Guy Edwardes / Southern yellow-billed hornbill (Tockus leucomelas) perched on branch, portrait. Savuti, Botswana.

Pedro Narra / Southern yellow-billed hornbill (Tockus leucomelas) head portrait, Moremi Game Reserve, Botswana.

Pedro Narra / Red-billed Hornbill (Tockus erythrorhynchus), and a Southern yellow-billed hornbill (Tockus leucomelas), Moremi Game Reserve, Botswana.

Jack Jeffrey/ BIA / Southern Yellow-billed Hornbill (Tockus leucomelas) with prey, Chobe National Park, Botswana