Fact file: Helmeted Hornbill (Rhinoplax vigil)

Helmeted Hornbill – Creative commons licence

IUCN statusCritically endangered
Population sizeNone Available (though a plan for population assessment was proposed in during the 2022 CITES Convention on International Trade of Endangered Species of Wild Flora and Fauna) (CITES)
Population trendRapidly decreasing (IUCN)
Unique evolutionary history14.56 million years (EDGE)

Why is the helmeted hornbill so special?

The helmeted hornbill is native to the old-growth lowland forests of Malaysia, Myanmar, Thailand, Sabah, Sarawak, Singapore, Kalimantan, Sumatra, Indonesia, and Brunei. The hornbills are best known for their bizarre puppet-like appearance. However, the social lives of helmeted hornbills are even more outrageous than their brightly colored leathery visages.

In most hornbills in the Rhinoplax genus, the ‘casque’, or keratinaceous horn on the upper mandible, is spongy and full of air pockets. This lightweight hollow structure allows the hornbill’s calls to be amplified and broadcast long distances across the forest. Helmeted hornbills, however, have a specially adapted casque that is entirely solid. This solid casque is harder and heavier than the casques of other hornbill species and is used for combat much like the horns of a bighorn ram. To defend foraging and nesting territories, helmeted hornbills fight off challengers by ramming their casques together in mid-air dog fights. The winners gain access to rare nesting cavities and figs from their favorite trees. The losers, on the other hand, win no more than a headache.

The nesting practices of helmeted hornbills resemble a depraved scatological retelling of Poe’s The Cask of Amontillado. First, a pair of hornbills must select the perfect nest. The female requires a cavity that is large enough in diameter to fit her body comfortably but shallow enough that her beak can reach the entrance from a seated position. Once they find the perfect home, the hornbills build a wall of regurgitated fruit and feces, sealing the cavity entrance with the female inside. Once safely trapped in the tree, the female hornbill molts all of her feathers and becomes entirely flightless. For the duration of incubation and chick rearing, the female will remain inside the cavity receiving food and expelling waste from a small opening in her vomit-and-scat wall. Though this nesting strategy may seem revolting to our human sensibilities, the enclosed nest provides protection from predators for both the flightless mother and her offspring. Once the breeding season is over and her chicks are ready to take flight, the female hornbill hammers on the wall with her powerful beak, freeing her family from their prison happy home.

What are the threats facing the helmeted hornbill?

Helmeted hornbills face a combination of habitat loss and illegal poaching threats. In 2018, the IUCN uplisted the species from “Near Threatened” to “Critically Endangered”, bypassing two categories and conveying the urgency of the species’ decline.

Female hornbills require large shallow nesting cavities that are primarily found in old-growth forests. As pristine forest is cleared to harvest lumber and convert land to oil palm plantations, helmeted hornbills lose critical nesting habitat and are unable to reproduce.

The dense colorful casque of the helmeted hornbill, known in the illegal wildlife trade as “golden ivory”, is coveted as a material for carved decorations and use in traditional Chinese medicine. For this reason, hornbills are poached by the thousands each year and their casques are exported for illegal sale. Though the wild population has not been surveyed to assess declines, the quantity of illegally trafficked casques seized by law enforcement in Thailand, Indonesia, and China have indicated an average annual loss of 6,000 birds each year.

Hornbill casque that has been carved for ornamental purposes – creative commons licence

What is being done to help save the helmeted hornbill from extinction?

Thailand’s National Park Act of 2019 protects critical nesting habitat for helmeted hornbills and the legal protection for the species has been increased from “Protected” to “Reserved”. These laws have increased penalties for illegal logging and poaching and have allocated law enforcement resources to the protection of the species.

Thailand’s Cybercrime Police began monitoring online marketplaces for the sale of illegal animal products including hornbill casques in 2017.

The Hornbill Research Foundation (HRF) implemented a research initiative in 2017 that provides training to an international staff. Researchers are currently working to estimate global populations of helmeted hornbills and better understand the species’ diet and breeding ecology.

If you love weird animals of all shapes and sizes and you want to see how you can help with WAWA’s conservation support, then please see how you can get involved here.

What can I do to help?

Financially supporting research and anti-poaching efforts can increase knowledge of the helmeted hornbill’s ecology and decreasing trafficking pressure on the species.

Purchasing products made with certified sustainable palm oil can help financially incentivize palm oil producers to implement methods that do not involve clearing old-growth forest.

Fighting poverty in the forest communities of Southeast Asia decreases the chances that individuals will turn to illegal means to make a living (such as poaching).


“HELMETED HORNBILL (RHINOPLAX VIGIL): REPORT OF THE SECRETARIAT”. 2022. CITES. Seventy-fourth meeting of the Standing Committee, Lyon, March 2022.

Rhinoplax vigil. 2018. The IUCN Red List of Threatened Species.

“Helmeted Hornbill”. 2017. Edge of Existence. http://www.edgeofexistence.org/species/helmeted-hornbill/

“Species factsheet: Rhinoplax vigil”. BirdLife International. 2023.