This trumpeter hornbill (Bycanistes bucinator) is sitting on a rock in front of Victoria Falls, or Mosi-oa-Tunya (’The Smoke that Thunders’), Zambezi River, Zimbabwe. These birds are called hornbills because of the strange protuberance, or casque, on their bill. (Photo copyright © by Kaj Halberg)
Hornbills are a family of birds, which is found in tropical Asia and Africa, comprising c. 53 species, of which c. 30 live in Africa. They vary greatly in size, from the small black dwarf hornbill (Tockus hartlaubi) in West Africa, which is 30 centimetres long and weighs only c. 100 grams, to the huge rhinoceros hornbill (Buceros rhinoceros) in Malaysia and Indonesia, and the southern ground-hornbill (Bucorvus leadbeateri) in Africa, both measuring c. 1.2 metres, and the ground-hornbill weighing up to 6.2 kilograms.
These birds are called hornbills because of a peculiar protuberance, or casque, on the bill of most species. Incidentally, the scientific name of the family, Bucerotidae, and of some species, Buceros, means ‘cow horn’ in the Greek. Hornbills are very noisy, and the casque is probably a means to increase the volume of their call, which carries quite a distance.
Hornbills feed mainly on various fruits, especially of fig trees (Ficus), but they also eat small animals like insects, scorpions, lizards, and snakes. When termites are swarming, hornbills often gather around termite mounds to eat the forthcoming insects. The two African species of ground-hornbills (Bucorvus) are quite different from other hornbills. They spend most of their time walking on the ground, catching small animals like lizards and insects.
Hornbills nest in hollow trees and are thus dependent on old growth forests. For this reason, many species have declined alarmingly during the last hundred years or so, as ever increasing areas of tropical forests have been cleared by humans.
The breeding habits of hornbills are very peculiar. When the female has laid her eggs inside a hollow tree, she will plaster the nest hole from inside, using her own guano which hardens in the air. Sometimes the male will help plastering the hole by bringing clay to the nest. The plaster makes it difficult for enemies like monkeys to eat eggs and young. Only a small opening is left, through which the male feeds the female during the whole incubation period. In some species, the female breaks the plaster, when the young are half grown, and then help the male feed the young – which will plaster the hole with their own guano when their mother has left! In other species, the female remains in the nest, until the young are full-grown. Meanwhile, the male brings food to all of them.
Throughout their distribution area, hornbills play an important role in tribal mythology, and their casque and feathers are widely used as ornaments. The casque of the helmeted hornbill (Rhinoplax vigil), of south-east Asia, is very heavy. Known as ho-ting, it is much praised by the Chinese, used for carving. Hornbill heads are often an ingredient in traditional Asian medicine.
Hornbills often call simultaneously, their powerful call carrying quite a distance. This picture shows calling silvery-cheeked hornbills (Bycanistes brevis), gathered in a tree, Lake Manyara National Park, Tanzania. (Photo copyright © by Kaj Halberg)
Silvery-cheeked hornbill (Bycanistes brevis), feeding on fruits of a fig tree (Ficus), Wondo Genet, Ethiopia. (Photo copyright © by Kaj Halberg)
When termites are swarming, hornbills often gather around termite mounds to eat the forthcoming insects. – Silvery-cheeked hornbill (Bycanistes brevis), Lake Manyara National Park, Tanzania. (Photo copyright © by Kaj Halberg)
One of the largest hornbills is the rhinoceros hornbill (Buceros rhinoceros), measuring more than 1.2 metres. It is found in Malaysia and Indonesia. (Photo copyright © by Kaj Halberg)
Trumpeter hornbill (Bycanistes bucinator), feeding on fruits of a fig tree, a favoured food item among these birds. – Zimbabwe. (Photo copyright © by Kaj Halberg)
The black-and-white-casqued hornbill (Bycanistes subcylindricus) lives in rain forests. This one was photographed in Kakamega Forest, western Kenya. (Photo copyright © by Kaj Halberg)
In several languages, smaller hornbill species of the genus Tockus are called tokos. Here, two southern yellow-billed hornbills (Tockus leucomelas) greet each other in the morning sun. – Matopos National Park, Zimbabwe. (Photo copyright © by Kaj Halberg)
Southern yellow-billed hornbill (Tockus leucomelas), Etosha National Park, Namibia. (Photo copyright © by Kaj Halberg)
Eastern yellow-billed hornbills (Tockus flavirostris), Samburu National Park, Kenya. (Photo copyright © by Kaj Halberg)
Formerly, all red-billed hornbills were regarded as a single species, Tockus erythrorhynchus, but recent DNA studies indicate that it should be split into five species, northern (T. erythrorhynchus), western (T. kempi), Tanzanian (T. ruahae), southern (T. rufirostris), and Damara (T. damarensis). Some authorities, though, still regard them as subspecies. This picture shows northern red-billed hornbill, feeding in a grassy area, Tarangire National Park, Tanzania. (Photo copyright © by Kaj Halberg)
Hemprich’s hornbill (Tockus hemprichii), Yabello, southern Ethiopia. (Photo copyright © by Kaj Halberg)
A female von der Decken’s hornbill (Tockus deckeni), Awash National Park, Ethiopia. (Photo copyright © by Kaj Halberg)
African grey hornbill (Tockus nasutus), Blue Nile, Ethiopia. (Photo copyright © by Kaj Halberg)
Jackson’s hornbill (Tockus jacksoni), Lake Baringo, Kenya. (Photo copyright © by Kaj Halberg)
Formerly, all smaller hornbill species of Africa and Asia were lumped together in one genus, Tockus. The smaller hornbills of the Indian Subcontinent, however, have now been moved to a genus of their own, Ocyceros. – This picture shows Indian grey hornbill (Ocyceros birostris), Keoladeo National Park, Rajasthan. (Photo copyright © by Kaj Halberg)
Male Malabar grey hornbill (Ocyceros griseus) in morning light, Mahaveer Wildlife Sanctuary, Goa, India. (Photo copyright © by Kaj Halberg)
The ground-hornbills differ quite a lot from other hornbills, spending most of their time feeding on the ground. This picture shows a southern ground-hornbill (Bucorvus leadbeateri), swallowing a beetle or some other insect. (Photo copyright © by Kaj Halberg)
The Abyssinian ground-hornbill (Bucorvus abyssinicus) is endemic to Ethiopia. This one was photographed near the Genale River. (Photo copyright © by Kaj Halberg)
In Borneo, a young girl of the Punan tribe performs a dance, with fans of hornbill feathers attached to her wrists. – Read more about the Punan people on this website, see Travel episodes: Borneo 1975 – Canoe trip with Punan tribals. (Photo copyright © by Kaj Halberg)
In tourist areas, hornbills often become remarkably tame. In this picture, Danish biologist Thomas Bregnballe is hand-feeding a northern red-billed hornbill (Tockus erythrorhynchus) in Samburu National Park, Kenya. (Photo copyright © by Kaj Halberg)
Hornbill heads are often used as an ingredient in traditional Asian medicine. In this picture, street vendors in Kathmandu, Nepal, have displayed some of their goods, such as heads of hornbills and ibises, scorpions, and dried lizards. (Photos copyright © by Kaj Halberg)
(Uploaded February 2016)
(Revised October 2017)