Lifestyle and Lifespan
Malayan Wreathed Hornbills are large birds, the male being the larger of the sexes. The birds are black with a long, white tail stained yellow with preen gland oil. The females have a black head and males have a rufous crown and nape, with a white face and neck. The iris and bare skin around the eyes are cherry red. Malayan Wreathed Hornbills have a long, heavy dull white bill with a casque of low wreathes across the base of the upper mandible. Below the beak is colorful gular pouch (pouch of inflatable skin); in females, the pouch is blue and in males the pouch is yellow. Both sexes have a blue-black band running through the bottom center of the pouch.
The Malayan Wreathed Hornbills, R. undulatus, is sometimes classified in the genus Aceros. There are two subspecies of Wreathed Hornbills: R. u. undulatus, and R. u. aequabilis. The Malayan Wreathed Hornbill is often called the Wreathed Hornbill or the Bar-pouched Hornbill after the bar running across the gular pouch beneath their bill. A closely related species, the Plain-pouched Hornbill (R. subruficollis), has similar coloration but lacks the band running across the gular pouch.
The first two vertebrae of Hornbills are fused to support the weight of a large, heavy bill and casque.
Malayan Wreathed Hornbills make their home in primary evergreen forested foothills, up to 8,700 feet.
The home range of the Malayan Wreathed Hornbill can be quite large, as they are a nomadic species. During breeding season, the home range is more restricted, about 10 kilometers squared, and up to 28 kilometers squared during the non-breeding season. Territories overlap both within the species and between other species. Population densities and spatial and temporal studies were performed in the Namdapha Tiger Reserve in northeast India, and found the average population density of Malayan Wreathed Hornbills to be 16 birds per kilometer, which is comparable to other study sites. Highest densities occurred during November and December, dropping to very low during the breeding season, just over 1 bird per kilometer, and no observations of breeding hornbills in the reserve. They are thought to breed in lower elevations than the reserve.
The Malayan Wreathed Hornbill eats mainly fruit, but the male may occasionally hunt small animals such as bats, frogs, reptiles, crabs and insects and bring them to the brooding female and chicks in the nest.
Malayan Wreathed Hornbills are excellent seed dispersers; they fly great distances and thus can distribute the seeds via their droppings over large areas. They depend on tall, emergent trees in tropical and subtropical lowland forests that have cavities far up on the trunk for their nests.
During the day, Malayan Wreathed Hornbills travel far and fly in flocks to communal feeding and bathing sites. At the end of the day, they return to shared roosting sites.
The hornbill's call from a perch is a repeated barking suing an inflatable throat pouch, called the gular pouch, and jerking the bill upward with each note.
Malayan Wreathed Hornbills often travel in flocks of up to 20 individuals. Feeding, roosting, and bathing sites are communal. Roosting sites may have up to 400 individuals.
These birds will pair-bond for life. The breeding season is variable across their range, starting earlier in the northernmost parts of their range and later in southern countries, but generally being spring and summer. About a week before egg-laying, the pair will find a tree cavity, preferably high on the trunk of an emergent tree, and the female will walled inside by the male using sticks and mud. An opening is left so that the male can deliver food to the female and later the chick as well. Nest cavities may be reused year after year. During incubation, the female will completely molt and regrow her feathers, and is dependent upon the male for food. She will stay in the cavity for 4 months.
Up to 3 eggs are laid in the nest cavity about a week after the female is walled in. She will stay inside first incubating the eggs, then brooding her chicks for 4 months. The male provides food for both the female and offspring during this time. When chicks are ready to fledge, the female breaks out of the cavity. Usually only one chick survives.
The Malayan Wreathed Hornbill is listed as Least Concern on the IUCN, and is on Appendix II of CITES.
The species, like most Hornbills, is considered in decline. Pressures from habitat loss and fragmentation through illegal logging and hunting are the biggest threats to all hornbill species. The species has been hunted for its meat, the feathers for ceremonial purposes, and the casque on top of their bill. The Malayan Wreathed Hornbill was added to CITES Appendix II in 1992, and is listed as Least Concern by the IUCN in 2016.
The Oakland Zoo is conservation partners with Hornbill Nest Project, centered in Thailand. The Hornbill Nest Project works with the rural communities in southeast Thailand by hiring them as nest protectors and monitors. The project also constructs and installs new nests in the areas they work in, and have education programs centered on learning about Hornbills.
When travelling, buy locally made goods so that the local communities can benefit directly from the wildlife they live next to, and be inspired to protect it.
The Malayan Wreathed Hornbill has long, broad wings that make a loud 'whooshing' sound when flying. The sound is produced by short underwing coverts that do not cover the flight quills.
The Javanese name 'Anggang tahon' means 'year bird', because of the cross ridges on the beak, however the hornbill does not form a new ridge every year. More than one ridge may form in a year and some of the front ridges may even drop off. Up to nine ridges have been counted, but the birds may live twenty years or more.
The Malayan Wreathed Hornbill appears to have eyelashes, but these are just modified feathers.
The male Wreathed Hornbill adjusts the food types and food delivery rates to the nest cavity, which reflects what is happening inside. During incubation, the male will increase his rate of delivery for a little while, to help the female regain nutrients that were lost after egg laying and will help during the molting process. Once the eggs have hatched, food delivery rates increase drastically. Additionally, more protein, calcium, and carbohydrates are delivered to the nest cavity during this time than while the female was incubating. Since they are fruit specialists, fruit makes up the majority of food delivered to the nest.
Hornbills have 4 toes; toes 1-3 point forward, and the 4th toe points backward. The second and third toe are partially fused (syndactyly), which allows them to better scramble through and along the tree branches for food.
Hornbills are the only birds to have a two-lobed kidney; all other birds have 3 lobed kidneys.