Neil Aldridge / Southern ground hornbill (Bucorvus leadbeateri) juvenile with an adult bird close by on the Selinda Reserve in northern Botswana. Vulnerable.

Mark Jones / Sulawesi Red-knobbed Hornbill (Aceros cassidix) breeding male in a fruiting Fig tree (Ficus forsteni) 32 meters above the ground in rainforest canopy, Tangkoko-Dua Saudara Nature Reserve, Sulawesi, In...

Karl Ammann / Ground hornbill {Bucorvus leadbeateri} with frog prey in beak, Kenya

Martin van Lokven / Ground Hornbill (Bucorvus leadbeateri) predating young Leopard Tortoise (Geochelone pardalis), Ngorongoro Conservation Area, Tanzania

Richard Du Toit / Southern ground hornbill (Bucorvus leadbeateri) on ground, Chobe National Park, Botswana

Richard Du Toit / Southern ground hornbill (Bucorvus leadbeateri) Kruger National Park, Limpopo Province; South Africa.

Richard Du Toit / Ground hornbill (Bucorvus leadbeateri) pair, Kruger National Park, Limpopo Province, South Africa.

Juergen & Christine Sohns / Ground Hornbill (Bucorvus leadbeateri), Kruger National Park, South Africa

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

Ernie Janes / Damara red-billed hornbill (Tockus damarensis) on ground, Namib desert, Sossusvlei, Namibia March

Tony Heald / Ground hornbill (Bucorvus leadbeateri) in flight, South Luangwa NP. Zambia. July.

Anup Shah / Southern ground hornbill (Bucorvus leadbeateri) male collecting food including lizard, snake and frog, Maasai Mara National Reserve, Kenya.

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 ground hornbill (Bucorvus leadbeateri) perched in a dead tree during summer, Kruger National Park, South Africa.

Richard Du Toit / Ground hornbill (Bucorvus leadbeateri) walking on road, Kruger National Park, South Africa.

Richard Du Toit / Ground hornbill (Bucorvus leadbeateri) portrait, Kruger National Park, South Africa.

Richard Du Toit / Ground Hornbill (Bucorvus leadbeateri), Kruger National Park, South Africa

Ashish & Shanthi Chandola / Southern red-billed hornbill (Tockus erythrorhynchus) Kruger National Park, South Africa, July.

Ashish & Shanthi Chandola / Southern ground hornbill (Bucorvus leadbeateri) male, Kruger National Park, South Africa, July.

Oliver Scholey / Ground hornbill (Bucorvus leadbeateri) feeding on frog, Masai Mara, Kenya.

Cheryl-Samantha Owen / Abyssian ground hornbill (Bucorvus abyssinicus) foraging in a field of beans. Commercial farm, Tanzania, East Africa.

Will Burrard-Lucas / Ground hornbill {Bucorvus leadbeateri} walking on the ground, South Luangwa National Park, Zambia. April.

Richard Du Toit / Ground Hornbill (Bucorvus leadbeateri) Kruger National Park, Limpopo Province, South Africa, October.

Richard Du Toit / Ground Hornbill (Bucorvus leadbeateri), Kruger National Park, South Africa

Wim van den Heever / Southern ground hornbill (Bucorvus leadbeateri) breaking open a termite mound, Chobe National Park, Botswana.

Loic Poidevin / Southern Ground Hornbill (Bucorvus leadbeateri) foraging, Masai Mara, Kenya.

Lou Coetzer / Southern ground hornbill (Bucorvus leadbeateri) in flight, Chobe River, Botswana, Vulnerable species.

Mike Wilkes / Silvery cheeked hornbill (Bycanistes brevis) foraging for insects on ground, Lake Manyara, Tanzania.

Eric Baccega / Southern Ground Hornbill (Bucorvus leadbeateri) feeding on insect, Masai Mara National Reserve, Kenya, Africa.

Walter Soestbergen / Ground Hornbill (Bucorvus leadbeateri) carrying grasshopper prey, South Africa

Denis-Huot / Ground hornbill (Bucorvus leadbearti) portrait, Nakuru National Park, Kenya

Denis-Huot / Ground hornbill (Bucorvus leadbearti) catching an insect, Masai-Mara Game Reserve, Kenya

Denis-Huot / Ground hornbill (Bucorvus leadbearti) catching a snake, Masai-Mara Game Reserve, Kenya

Denis-Huot / Ground hornbill (Bucorvus leadbearti) catching a hare, Masai-Mara Game Reserve, Kenya

Tony Heald / Bradfield's Hornbill (Tockus bradfieldi) portrait, Hwange National Park, Zimbabwe October 2012

Murray Cooper / Ground Hornbill (Bucorvus leadbeateri) male, Kruger National Park, South Africa

Christophe Courteau / Ground Hornbill (Bucorvus leadbeateri) Okavango delta, Botswana

Charlie Summers / Southern Ground hornbill (Bucorvus leadbeateri) gathering nesting material in a riverbed in Lake Manyara National Park, Tanzania

Charlie Summers / Southern Ground hornbill (Bucorvus leadbeateri) gathering nesting material in a riverbed in Lake Manyara National Park, Tanzania

Richard Du Toit / Ground Hornbill (Bucorvus leadbeateri) in tree, Kruger National Park, South Africa

Matthias Breiter / Ground Hornbill (Bucorvus leadbeateri), Okavango Delta, Botswana

Ole Jorgen Liodden / Southern Ground Hornbill (Bucorvus leadbeateri) about to catch a large beetle in its beak. Masai Mara, Kenya, September.

Anup Shah / Southern ground hornbill (Bucorvus leadbeateri)Masai Mara National Reserve, Kenya

Mary McDonald / Ground hornbill (Bucorvus leadbeateri / cafer)hunting, with grasshopper caught in mid air, wings spread, Masai Mara Game Reserve, Kenya, East Africa, Vulnerable species

Brent Stephenson / Male Southern Ground-hornbill (Bucorvus leadbeateri) hunting for prey in long grass. Kruger National Park, South Africa, January.

Pete Oxford / Southern Ground Hornbill (Bucorvus leadbeateri). Kruger National Park, South Africa, December.

Konstantin Mikhailov / Ground hornbill (Bucorvus leadbeateri) captive, from South Africa

Konstantin Mikhailov / Ground hornbills (Bucorvus leadbeateri) captive, from South Africa

Anup Shah / Southern ground hornbills (Bucorvus cafer) feeding on a carcass. Masai Mara National Reserve, Kenya, September 2009

Anup Shah / Female Southern Ground- hornbill (Bucorvus leadbeateri) feeding. Masai Mara National Reserve, Kenya. March

Patricio Robles Gil / Southern Ground Hornbill (Bucorvus leadbeateri) resting in shade, Kruger NP, South Africa

Patricio Robles Gil / Southern Ground Hornbill (Bucorvus leadbeateri) resting in shade, Kruger NP, South Africa

Patricio Robles Gil / Southern Ground Hornbill (Bucorvus leadbeateri) resting in shade, Kruger NP, South Africa

Patricio Robles Gil / Southern Ground Hornbill ( bucorvus leadbeateri) juvenile feeding on snake that has been given to it by the adult, Kruger NP, South Africa

Patricio Robles Gil / Southern Ground Hornbill ( bucorvus leadbeateri) juvenile feeding on snake that has been given to it by the adult, Kruger NP, South Africa

Patricio Robles Gil / Southern Ground Hornbill (Bucorvus leadbeateri) carrying tortoise prey to nest, Kruger NP, South Africa

Patricio Robles Gil / Southern Ground Hornbill (Bucorvus leadbeateri) feeding on tortoise prey, Kruger NP, South Africa

Patricio Robles Gil / Southern Ground Hornbill (Bucorvus leadbeateri) flying to nest with food for chicks, Kruger NP, South Africa

Richard Du Toit / Ground Hornbill (Bucorvus leadbeateri) juvenile, Chobe National Park, Botswana

Kim Taylor / Monteiro's hornbill (Tockus monteiri) on ground, Namibia, Africa

Piper Mackay / Adult and juvenile Southern ground-hornbill(Bucorvus leadbeateri / cafer) interacting, Masai Mara, Kenya

Tim Laman / Southern Ground hornbill (Bucorvus leadbeateri / cafer) male in the grass. Kruger National Park, South Africa.

Tim Laman / Various seeds of rainforest trees on the ground below the nest cavity, regurgitated by Rufous-necked hornbills (Aceros nipalensis) note also uneaten cicadas, Huai Kha Khaeng Wildlife Sanctuary, Thaila...

Tim Laman / Southern Ground hornbill (Bucorvus leadbeateri / cafer) female portrait. Kruger National Park, South Africa.

Tim Laman / Southern Ground hornbill (Bucorvus leadbeateri / cafer) dust bathing to clean feathers of parasites, Kruger National Park, South Africa.

Tim Laman / Knobbed hornbill (Aceros cassidix) fledgling chick on the ground after emerging from nest (perhaps too early to fly?) Tangkoko Batuangus / Dua Saudara Nature Reserve, Sulawesi Island, Indonesia.

Tim Laman / Southern Ground hornbill (Bucorvus leabeateri / cafer) in flight. Kruger National Park, South Africa.

Tim Laman / Southern Ground hornbill (Bucorvus leadbeateri / cafer) chick in nest hollow in Baobab tree. Kruger National Park, South Africa.

Tim Laman / Southern ground hornbill (Bucorvus leadbeateri / cafer) crushes skull of mouse it has captured before swallowing, Kruger National Park, South Africa.

Tim Laman / Southern Ground Hornbill (Bucorvus leadbeateri / cafer) in Giant bayobab nest tree, Kruger National Park, South Africa.

Tim Laman / Red-billed hornbill (Tockus erythrorhynchus) on ground holding a beetle in its beak. Kruger National Park, South Africa.

Vincent Grafhorst / Ground Hornbill (Bucorvus leadbeateri) male on the Khwai River floodplain with an insect in its bill, Moremi Game Reserve, Okavango Delta, Botswana

Vincent Grafhorst / Ground Hornbill (Bucorvus leadbeateri) juvenile in the grass of the Khwai River floodplain, Moremi Game Reserve, Okavango Delta, Botswana

Sharon Heald / Ground hornbill (Bucorvus leadbeateri) walking, Chobe National Park, Botswana May 2008.

Michael Hutchinson / Red-billed hornbill {Tockus erythrorhynchus} on ground, Lewa Downs, Kenya.

ZSSD / Abyssinian Ground Hornbill (Bucorvus abyssinicus) flying, native to Africa

ZSSD / Abyssinian Ground Hornbill (Bucorvus abyssinicus) portrait, native to Africa

ZSSD / Abyssinian Ground Hornbill (Bucorvus abyssinicus) portrait, native to Africa

TJ Rich / Southern Ground hornbill feeding (Bucorvus leadbeateri) Masai Mara National Reserve, Kenya

John Cancalosi / Portrait of Leadbeaters ground hornbill (Bucorvus leadbeateri) carrying insect prey, Kenya, East Africa, captive

Peter Blackwell / Group of Ground hornbills (Bucorvus leadbeateri) picking maggots from Wildebeest carcass, Masai Mara GR, Kenya

Doug Perrine / Ground hornbill {Bucorvus leadbeateri} feeding on snake, Transkei, South Africa

DAVID TIPLING / Ground Hornbill {Bucorvus leadbeateri} close-up of face, Masai Mara, Kenya.

Bernard Castelein / Ground hornbill (Bucorvus leadbeateri) Masai Mara, Kenya

Rod Williams / Juvenile Abyssinian ground hornbill head portrait {Bucorvus abyssinicus} captive

Luiz Claudio Marigo / Ground hornbill preying on caterpillars {Bucorvus leadbeateri} Masai Mara, Kenya

Andrew Parkinson / Ground hornbill {Bucorvus leadbeateri} catching and eating grasshopper. Moremi GR Botswana

Richard Du Toit / Ground hornbill landing {Bucorvus leadbeateri} Moremi WR, Botswana

Richard Du Toit / Ground Hornbill (Bucorvus leadbeateri) adult calling in grassland, Chobe National Park, Botswana

Tui De Roy / Sulawesi Red-knobbed Hornbill (Aceros cassidix) breeding male in a fruiting Fig (Ficus forsteni) tree, 32 meters above the ground in rainforest canopy, Tangkoko-Dua Saudara Nature Reserve, Sulawesi, I...

Jabruson / Ground hornbills feeding and display. {Bucorvus leadbeateri} Tsavo East NP, Kenya

Richard Du Toit / Ground hornbill catching insect {Bucorvus leadbeateri} Savute Chobe NP, Botswana

Peter Blackwell / Ground hornbill head portrait {Bucorvus leadbeateri} Kenya, Africa

Sharon Heald / Ground hornbill walking {Bucorvus leadbeateri} Moremi WR, Botswana, Southern Africa

Tony Heald / Ground hornbill {Bucorvus leadbeateri} with frog prey Moremi WR, Botswana

Peter Blackwell / Ground hornbill, Masai Mara GR, Kenya