Learn more about this rainforest rarity, its fascinating behaviours and the threats it faces.
The lowland rainforests of Sumatra are one of the rarest habitats in the world, home to Critically Endangered Sumatran Tigers and Sumatran Elephants. Stand beneath the tree canopy here, and the soundscape swells around you: the growl of the Sun Bear, the ghostly call of gibbons, the white-noise-like hum of bugs. This slice of tropical paradise is a biodiversity hotspot.
A loud, cackling sound erupts from the canopy, starting with slow hoots and building to a human-sounding laugh – a Helmeted Hornbill. Gliding overhead, this bird navigates between the dense trees with ease, despite its five-and-a-half-foot wingspan and 50cm-long tail feathers.
Perching on a branch stump, the male Hornbill leans towards a cavity in the tree’s trunk, where its partner and chick are hidden away. The female won’t leave the nest for up to 150 days, taking full-time care of their chick – even sealing herself inside, leaving only a tiny hole open – fully reliant on this male for food. These dedicated, monogamous parents, who can live up to 50 years, produce just one chick per year.
Despite their unmistakable appearance and distinctive call, these birds are notoriously difficult to see, as they prefer intact, undisturbed areas of rainforest.
These birds participate in a behaviour known as ‘aerial jousting’ to defend their territories or food resources. It’s a mid-air clash of their ‘casques’ – that’s the large keratin plate at the front of the head, from which the bird gets its name.
Helmeted Hornbills are Critically Endangered owing to several key threats.
The demand for the keratin casque makes this bird a highly prized species for poachers. Carved to make jewellery and ornaments, there’s an underground illegal trade across parts of Asia, including China. Following soaring demand, in 2015, the Helmeted Hornbill’s status was elevated from Near Threatened to Critically Endangered, due to this high poaching pressure.
If a male bird is lost to poaching in the breeding season, its dependent partner and chick – still sealed inside the nest – no longer have any means of accessing food
These birds are highly specialised, adapted to live among the rainforest ecosystem. Unable to cling to tree trunks, like other hornbill species, due to their extra-long tail feathers, the male must be able to access the nest cavity by perching on a stump at the cavity entrance. They nest in large, living trees – which tend to be those targeted most by illegal logging.
The Sumatran rainforests have historically been – and are still being – deforested due to competing land pressures, including massive expansion of oil palm plantations, human settlements and illegal logging. Similarly, deforestation continues in other parts of the Helmeted Hornbill’s range, which also covers Borneo, Peninsular Malaysia, southern Myanmar and southern Thailand.
In 2007, the RSPB partnered with Burung Indonesia and BirdLife International to pioneer a new rainforest conservation approach through policy. Three partners are now protecting and managing Hutan Harapan, which means Rainforest of Hope.
This large-scale conservation project spans almost 100,000 hectares of Indonesian rainforest. That’s around 20% of the low-lying rainforest on the island of Sumatra, Indonesia; and two-thirds the size of our all of our UK nature reserves combined!
Among the amazing wildlife in Hutan Harapan, there are nine species of hornbill, including Helmeted Hornbills. We’re working with partners and local communities towards increasing protection for these species. In the past, logging was undertaken at Hutan Harapan. As we restore and protect the forest, we’re working to join up key fragments of Helmeted Hornbill habitat by planting food plants and nesting trees for the future.
We’re working to protect a precious stretch of rainforest on the Indonesian island of Sumatra.
By collating existing data and gathering new information from hornbill surveys in 2026, we’re painting a picture of how these birds are currently faring in Hutan Harapan, and identifying the existing areas of habitat which need the most protection.
We’re exploring ways to support our BirdLife partners in Asia, to help address illegal trade in Helmeted Hornbill casques as materials. Unfortunately, this is a difficult task, due to niche illegal markets operating ‘underground’.
Our Species Lead for Helmeted Hornbills has supported Hong Kong Bird Watching Society in running educational events based around the children’s book, ‘The Tallest Tree, A Rainforest Adventure'.
The story aims to raise awareness about illegal wildlife trade. Published by the Hong Kong Bird Watching Society (HKBWS), funds from UK sales of the book support relevant conservation projects via the Oriental Bird Club (OBC). Both HKBWS and OBC have recently directed funds generated from the book’s sales to support a genetic study of Helmeted Hornbill casques and their geographical origins, helping to shed light on illegal trade routes. We are now hoping to produce an Indonesian edition of the book for our partners in Hutan Harapan to use as an educational resource.
Written by Jacqueline Weir, RSPB Ecologist and our Helmeted Hornbill Species Lead, and illustrated by Lilian Fu, this children’s book follows the adventures of Bill the Helmeted Hornbill and Trixie the pangolin.
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To ensure we can support Helmeted Hornbill’s as effectively as possible, we’ve designated them one of our 100 RSPB priority species. This means we’re focussing our efforts on researching and helping their populations recover.
These rainforest rarities are currently on the ‘Diagnosis’ stage of the species recovery curve within Hutan Harapan. That means we’re working to diagnose the causes of the Helmeted Hornbill’s decline locally as well as looking for, and testing, conservation solutions.
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