The Helmeted Hornbill: A Bizarre and Endangered Bird
An Unusual Bird
The helmeted hornbill is one of the most bizarre birds in existence. The animal has a huge bill that has a large, solid protuberance called a casque on the top. The casque is so big that it often makes the head look bald. The bird also has a big patch of featherless, leathery skin on its neck. This area is blue in females and red in males.
The hornbill's behaviour is also strange. Its call is a noisy series of hoots followed by a laughing sound which is often described as “maniacal”. The birds - especially the males - perform dramatic aerial displays that end in noisy collisions as the casques of different animals collide. During nesting the female is sealed in a tree hole with a plaster made of some combination of mud, clay and sticky fruit. Only a small opening is left so that the male can feed his mate with regurgitated food.
This fascinating bird is currently in very serious trouble. It's a critically endangered species, mainly due to illegal hunting for its casque. Unless protection laws are enforced, the animal could become extinct in the near future.
Range of the Helmeted Hornbill
Helmeted hornbills (Rhinoplax vigil) live in evergreen forests of Southeast Asia. They are found in Myanmar, Thailand, Malaysia, Sumatra and Borneo.
It's impossible to ignore the helmeted hornbill when it's either seen or heard. Its appearance and behaviour demand attention. The casque, or helmet, is one of the most noticeable body parts. Other birds have casques, but these are hollow, lightweight structures. The helmeted hornbill's casque is solid. It's made of keratin, the material that makes up our finger and toenails. The casque and the rest of the bill are red or yellow in colour. The leathery skin on the hornbill's neck is also noticeable. It looks very odd on a bird's body.
Helmeted hornbills are mainly black in colour, but the belly and leg feathers are white. The tail is also white, except for a horizontal black band. The central tail feathers may be almost as long as the rest of the body. There are tufts of brown feathers extending from the back of the bird's eyes.
Males weigh about 3.1 kilograms (6.8 pounds) while females weigh around 2.7 kilograms (5.9 pounds). Although helmeted hornbills are big, they aren't the heaviest hornbill in Asia. This honour goes to the great hornbill, which may weigh up to 4 kg, or 8.8 pounds.
Eating and Hopping
Hornbills belong to the family Bucerotidae. Ground hornbills have a slightly different anatomy from the arboreal species. They move by walking or running over the ground instead of by hopping. Some researchers think that the ground hornbills should be classified in their own family.
There are other members of the hornbill family besides the helmeted hornbill. They all have large beaks and sometimes have a casque. Only the helmeted hornbill has a solid casque, however. In other hornbills the casque is spongy in texture and the beak is usually curved downwards.
The function or functions of the casque are still being investigated. It's usually larger in males than in females. Its formation indicates reproductive maturity. In at least one species of hornbill, the casque acts as a resonating chamber for sound. In helmeted hornbills the casque reinforces the beak.
The first two neck vertebrae of hornbills are joined together. The birds also have strong neck muscles. These features are thought to have developed in order to support the heavy beak.
Feeding and Preening
The diet of helmeted hornbills consists mainly of fruit, especially figs. The birds are an important distributor of seeds in the forest. They also eat small animals, including mammals, reptiles, smaller birds and insects. Hornbills have good vision, which is useful as they hunt for food. It's believed that they can see the tip of their own beaks. This is an unusual ability in birds.
The birds use their strong beaks to dig under bark to find insects. The weight of the casque enables the animals to use their beak like a hammer, while the two beak tips act like tweezers as a bird picks up food. The tongue is too short to reach food that is picked up by the end of the beak, so the food is passed to the back of the throat with a jerking motion.
The birds prefer to forage high in the tree canopy and generally search for food alone. Arboreal (tree-living) hornbills hop along branches or over the ground, moving both of their feet together. Air rushes through the birds' wings as they fly from tree to tree, making the flight a noisy event, especially when a group of hornbills are moving together.
The hornbill spends part of its day preening its feathers to keep them in good condition. The yellow beak is coloured red by an oily secretion from the preen gland, which is located at the base of the tail. The bird uses its beak to rub this secretion over its feathers.
The dense casque of a helmeted hornbill means that the head accounts for ten percent of the bird's weight. This feature is useful during displays. The aerial displays and casque collisions, often referred to as jousting, are often seen around fig trees. These are the hornbill's favourite source of food. The jousting is thought to be a way to compete for the figs.
Males seem to joust far more frequently than females. Before he takes flight, a perched male hits tree branches with his beak and rubs the beak from side to side over the branch. He may also call. Then he takes off and flies towards another bird, who is also flying. Loud clacks travel through the forest as the birds' casques collide. Even though the birds slow to a glide just before hitting each other, they may actually flip upside down as a result of the collision.
After they've collided, the jousting birds return to a tree branch to perch. They pause briefly and then often take off for another collision. The displays and collisions occur repeatedly in sessions that last for as long as two hours.
Breeding helmeted hornbills are territorial. After courtship and mating displays, the birds choose a tree cavity for a nest. The female enters the cavity and then seals the opening, sometimes with the male's help. He brings her useful materials to help her, such as mud, clay and fruit. A narrow slit is left as an opening through which the male feeds the female and the youngster. Although the full details of the hornbill's reproduction are unknown, the female appears to lay only one egg.
The female stays inside the hole for several months. When the egg has hatched and the young hornbill is old enough to be left alone in the nest, the female breaks out of the nest and then rebuilds the wall until the youngstar is ready to fly. The single egg and long rearing time mean that the hornbill has a low reproductive rate.
All hornbill females incubate their eggs within a hole that is partially sealed by either the male or the female, with the exception of the two species of ground hornbills in Africa.
IUCN Red List Categories
The IUCN Red List
The IUCN (International Union for Conservation of Nature) has established a Red List. The list is a database which describes animal species and assigns them a rating based on their closeness to extinction.
The IUCN ratings from the least serious status to the most serious are shown below. The first two ratings are sometimes omitted from reports.
- NE or Not Evaluated
- DD or Data Deficient
- LC or Least Concern
- NT or Near Threatened
- VU or Vulnerable
- EN or Endangered
- CR or Critically Endangered
- EW or Extinct in the Wild
- EX or Extinct
When I wrote the first edition of this article in 2011, the helmeted hornbill was classified in the Near Threatened category. In 2015, IUCN officials reclassified the bird as Critically Endangered, jumping over two categories in the process. Such a rapid and major change in population status is very troubling.
The solid casque of helmeted hornbills is in high demand as an ivory substitute, even though it's made of keratin. Keratin is a fibrous protein that is also found in human hair and nails and in animal claws, hooves and horns. The material in the casque is often called hornbill ivory or golden jade.
Hunters kill the hornbills for both their casque and their long tail feathers. The casque is carved to make ornaments and jewelry and the feathers are used to make head and clothing decorations. The hornbill population is currently experiencing intense hunting pressure.
Deforestation is also affecting the population. The trees in which the bird lives and breeds are being removed. There is a growing trend in many parts of the world to clear land of forests in order to use it for agriculture or development. The loss of the forest is a serious problem for hornbills and other creatures.
The Future for Helmeted Hornbills
Many people are aware of the horrendous slaughter of elephants for the ivory in their tusks and and are quite rightly protesting this activity. The plight of the helmeted hornbill is less well known. Another problem seems to be that although laws are in place to protect the birds, the laws are either not being enforced or are being circumvented. The IUCN says that helmeted hornbills will likely be extinct within three generations unless major changes are made. Extinction due to human activity is a sad fate for an animal.
© 2011 Linda Crampton