There are some bizarre birds in the world and the helmeted hornbill is one of them. Others are the great frigatebird and the hoatzin. The great frigatebird develops a large, bright red inflatable sac under its bill during the breeding season and the hoatzin stinks to high heaven all the time.
The strange protuberance on the beak of the hornbill and its unusual antics qualify it as bizarre.
Hornbills are found in tropical and subtropical Africa, Asia and Melanesia. The Punan ethnic group of Sarawak, Malaysia, believe that a large helmeted hornbill guards the river between life and death.
A characteristic of the hornbills is the long, down-curved bill, which is often brightly coloured and may have a casque on the upper mandible. An adaptation of the hornbill to support the heavy beak and casque is the strong neck muscles and the joining of the first two neck vertebrae. The casque is made of keratin which is found in the hooves, horns and claws of mammals and the hair and nails of humans. Hornbills also have a two-lobed kidney.Credit: By Citron (Own work) [GFDL (www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
The helmeted hornbill is the only species to have a solid casque. The casque is a large, solid protuberance, like that of the cassowary. The casque of other hornbills has a spongy texture. The casque only occurs is sexually mature birds and is larger in males. In this species, the casque reinforces the chisel-like beak.
The helmeted hornbill has the scientific name of Rhinoplax vigil.
The hornbill is found from Myanmar and Thailand through Malayasia to Sumatra and Borneo. Although it was once found in Singapore, it is now regarded as extinct there.
Its preferred habitat is primary evergreen forest in rugged terrain. It is found at elevations up to 1,500 metres.
The bird has a huge red or yellow bill and a casque on the top of the head. The dense casque makes up 10% of the bird’s weight and extends from the base of the bill halfway to the tip. It ends suddenly at this point. The casque and bill are yellow but the sides and top of the casque as well as the base of the beak become red from the secretions of the preen gland, often leaving the front of the casque and part of the beak yellow.
There is a patch of bare, leathery, wrinkled skin on the neck. This is blue in females and red in males. The upperparts are mostly dark brown with white belly and leg feathers. Chestnut-brown feathers extend in tufts from the back of the eyes and the two middle tail feathers are very long (up to a metre) and white with dark bands.
The total body length (body and tail) is about 1.6 metres. Males weigh around 3.1 kg and females 2.7 kgs. The hornbill has a preen gland at the base of the tail. Oily secretions from the gland keep the plumage in good condition and it is this oily substance which turns the beak and casque red.
The hornbill has a maniacal cackle which consists of a noisy series of hoots followed by a laughing sound.
An unusual activity in which the birds engage is ‘jousing’. Pairs of birds (generally males) engage in this activity. A perched male will slap branches with his beak and rub the beak to and fro on the branch. He will then fly towards another bird and the pair will collide. These aerial displays and collisions occur repeatedly over a period of several hours. Collisions take place as the birds glide and it not unknown for the birds to flip upside down or be pushed backwards as they hit. As the casques hit each other, the loud ‘clack’ can be heard for some considerable distance.
These encounters often take place around the fig trees and it is thought that they might be disputes over feeding rights.Credit: By Hydrocorax (Own work) [CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0) or GFDL (www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons
The birds are sedentary, unlike many fruit-eating hornbills. A group of helmeted hornbills make quite a noise when flying as the air rushes through their wings. When moving on the ground or along branches, they move with both feet together.
Another unusual practice is that of sealing females in their nests during incubation of the eggs. One source states that the male seals the female in while another says the female seals herself in with the male bringing her mud, fruit and other useful material with which to do so!
Hornbills eat mainly fruit, especially figs. Small mammals, reptiles and smaller birds are also eaten. The strong bill is used to prise insects from under the bark, the casque acting as extra weight to aid the chisel-like beak in its work. The tip of the beak acts as a pair of tweezers. Food is picked up on the end of the beak but the tongue is too short to reach the food and is passed to the back of the throat with a jerking motion. Hornbills may hang upside down when prising bark to get at hidden insects. Foraging occurs high in the forest canopy.
Hornbills are territorial. After courtship and mating, nests are made in a tree cavity. The female enters the cavity and the opening is sealed. Once the female is sealed in,the male then feeds the female and later the chicks with regurgitated food. A narrow slit in the nest allows him to do this. After several months, when the chicks can be left alone in the nest, the female breaks out but rebuilds the wall until the juveniles are ready to fly.
The material in the casque commands a high price as an ivory substitute. It is called hornbill ivory or golden jade. It is valued for carved ornaments and jewellery. The long tail feathers are also used for decorative head-dresses and to adorn dancing cloaks of indigenous tribes. So hunting is a major threat to the hornbill.
Deforestation also has an effect, although as the hornbill lives in remote forests, this is taking longer to have an impact. However, populations of the hornbill are decreasing.
During the late 1990s, forest fires also had a big impact on the hornbill’s habitat.
The IUCN lists the helmeted thornbill as ‘near threatened’. It is listed on Appendix I of the Convention on International Trade in Endangered Species (CITES).
These bizarre birds have a unique place in the amazing natural world.