Ernie Janes / Trumpeter hornbill (Bycanistes bucinator) feeding, captive.

Ernie Janes / Trumpeter hornbill (Bycanistes bucinator) feeding, captive.

Christophe Courteau / Black and white Casqued hornbill (Bycanistes subcylindricus) up in tree, Kibale NP, Uganda.

Loic Poidevin / Silvery cheeked hornbill (Bycanistes brevis) captive at zoo, native to Africa.

Bruno D'Amicis / Silvery-cheeked hornbill (Bycanistes brevis) male perched, Jimba, Lake Tana Biosphere Reserve, Ethiopia.

Bruno D'Amicis / Silvery-cheeked hornbill (Bycanistes brevis) female perched, Jimba, Lake Tana Biosphere Reserve, Ethiopia.

Cyril Ruoso / Bush meat hunter with White thighed hornbill (Bycanistes albotibialis) Cross River State, Nigeria.

Anup Shah / Black-and-white casqued hornbill (Ceratogymna subcylindricus subquadratus) male sitting in a Bottle Brush tree. Kakamega Forest South, Western Province, Kenya.

Denis-Huot / Silvery-cheeked Hornbill (Bycanistes brevis) close-up at zoo, occurs in East Africa.

Denis-Huot / Silvery-cheeked Hornbill (Bycanistes brevis) close-up at zoo, occurs in East Africa.

Denis-Huot / Silvery-cheeked Hornbill (Bycanistes brevis) close-up, zoo, Doué La Fontaine, France

Denis-Huot / Silvery-cheeked Hornbill (Bycanistes brevis) close-up at zoo, occurs in East Africa.

Denis-Huot / Silvery-cheeked Hornbill (Bycanistes brevis) close-up at zoo, occurs in East Africa.

Mike Wilkes / Silvery cheeked hornbill (Bycanistes brevis) perched in tree, Lake Manyara, Tanzania.

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

Jabruson / Bushmeat on motorbike for commercial meat trade including Brush-tailed Porcupine (Atherurus africanus) and White-thighed Hornbill (Bycanistes cylindricus albotibialis), Ouesso - Makoua highway, Odzala...

Jabruson / Bushmeat for sale at market including male Black-wattled Hornbill (Ceratogymna atrata) and male White-thighed Hornbill (Bycanistes cylindricus albotibialis). Mbomo, Odzala-Kokoua National Park, Republ...

Jabruson / Bushmeat for sale at market including male Black-wattled Hornbill (Ceratogymna atrata) and male White-thighed Hornbill (Bycanistes cylindricus albotibialis). Mbomo, Odzala-Kokoua National Park, Republ...

Jabruson / Bushmeat for sale at market including male Black-wattled Hornbill (Ceratogymna atrata) and male White-thighed Hornbill (Bycanistes cylindricus albotibialis). Mbomo, Odzala-Kokoua National Park, Republ...

Jabruson / Bushmeat for sale at market including male White-thighed Hornbill (Bycanistes cylindricus albotibialis). Mbomo, Odzala-Kokoua National Park, Republic of Congo, May 2005.

Jabruson / Bushmeat for sale at market including male Black-wattled Hornbill (Ceratogymna atrata) and male White-thighed Hornbill (Bycanistes cylindricus albotibialis). Mbomo, Odzala-Kokoua National Park, Repub...

Chien Lee / Grey-cheeked Hornbill (Bycanistes subcylindricus) female, Kibale National Reserve, Uganda

Winfried Wisniewski / Grey-cheeked Hornbill (Bycanistes subcylindricus) calling, Masai Mara, Kenya

Jabruson / White-thighed Hornbill (Bycanistes albotibialis) feeding on 'Cafe Tingunda' fruit. Bai Hokou, Dzanga-Ndoki National Park, Central African Republic

Florian Möllers / Pair of Black-and-White Casked Hornbill (Bycanistes subcylindricus) perched in a tree, calling. Budongo Forest Reserve, Masindi, Uganda, Africa. December

Florian Möllers / Pair of Black-and-White Casked Hornbill (Bycanistes subcylindricus) perched in a tree preening. Budongo Forest Reserve, Masindi, Uganda, Africa. December

Florian Möllers / Male Black-and-White Casked Hornbill (Bycanistes subcylindricus) perched in tree. Budongo Forest Reserve, Masindi, Uganda, Africa. December

Tony Heald / Trumpeter hornbill [Bycanistes bucinator] male perched, Chobe National Park, Botswana, August

Nick Garbutt / Silvery-cheeked Hornbill (Bycanistes brevis) adult perched on dead branch, Lake Manyara National Park, Tanzania. March.

Bruno D'Amicis / Silvery cheecked Hornbill (Bycanistes brevis) adult male, Kaffa, Southern Ethiopia, East Africa December 2008

Bruno D'Amicis / Silvery-cheeked hornbill (Bycanistes brevis) male in flight, Kaffa zone, Southern Ethiopia, East Africa December 2008

David Pike / Black and white casqued hornbill {Bycanistes subcylindricus} Masai Mara, Kenya

Richard Du Toit / Trumpeter hornbill male {Bycanistes bucinator} Kruger NP, South Africa

Jabruson / Piping hornbill in tree, Epulu Ituri Reserve, DR Congo (formerly Zaire)

Joel Sartore / Photo Ark / Black-and-white-casqued hornbill (Bycanistes subcylindricus subquadratus) female looking around with its beak open, Vogelpark Turnersee, St. Primus. Captive.

Joel Sartore / Photo Ark / Trumpeter hornbill (Bycanistes bucinator) female, portrait, Fresno Chaffee Zoo, California. Captive, occurs in Africa.

Joel Sartore / Photo Ark / Trumpeter hornbill (Bycanistes bucinator) female, head portrait, Fresno Chaffee Zoo, California. Captive, occurs in Africa.

Joel Sartore / Photo Ark / White-thighed hornbill (Bycanistes albotibialis) female, head portrait, North Florida Wildlife Center. Captive, occurs in Africa.

Joel Sartore / Photo Ark / White-thighed hornbill (Bycanistes albotibialis) female, head portrait, North Florida Wildlife Center. Captive, occurs in Africa.

Loic Poidevin / Silvery-cheeked hornbill (Bycanistes brevis) perched on branch. Uganda.

Joel Sartore / Photo Ark / Trumpeter hornbill (Bycanistes bucinator) looking around, Fresno Chaffee Zoo, California, USA.

Joel Sartore / Photo Ark / A close up of a Trumpeter hornbill's (Bycanistes bucinator) head. The animal looks around. Fresno Chaffee Zoo, California, USA.

Joel Sartore / Photo Ark / White-thighed hornbill (Bycanistes albotibialis) female close up of head looking around, North Florida Wildlife Center. Captive.

Bruno D'Amicis / Silvery-cheeked hornbill (Bycanistes brevis) male perched on branch. Zege Peninsula, Ethiopia.

Bruno D'Amicis / Silvery-cheeked hornbill (Bycanistes brevis) male perched in tree. Zege Peninsula, Ethiopia.