Family Hornbills (Bucerotidae)


Knobbed Hornbill (Rhyticeros cassidix)


French: Calao à cimier German: Helmhornvogel Spanish: Cálao grande de Célebes
Other common names: Sulawesi Wrinkled Hornbill

Buceros cassidix


, 1823,



Affinities unclear; could be separated in a monotypic genus Cranorrhinus (sister to Rhyticeros) on account of divergent phenotype#R#R; further analyses required. Previously considered to belong in the species-group centred on Rhabdotorrhinus leucocephalus (which see). Birds from Muna and Butung, smaller and shorter-billed, proposed as race brevirostris, but variation clinal. Monotypic.


Sulawesi, and offshore islands of Lembeh, Togian Is, Muna and Butung.

Descriptive notes

70–80 cm; male 2360–2500 g. Large hornbill with white tail and high casque. Male crown and nape deep rufous, head sides and neck paler rufous to creamy, body and... read more


A repeated, short gruff bark “grrok”, sometimes interspersed with more subdued croaking notes.


Evergreen forest at up to 1800 m, especially in lowlands below 1100 m, where extends into patches... read more

Food and feeding

Mainly fruit; also animal food, including insects, and bird eggs and nestlings, but only 1% of diet. Fruits of at least 35 plant species in... read more


Lays in Jun–Sept; season probably triggered by end of rains, so that fruiting peaks when chick fledges. Nests in pairs. Nest in... read more


Wanders locally during non-breeding season in search of food, especially large red figs; moves in... read more

Status and conservation

VULNERABLE. CITES II. Locally very common, especially in areas with many fig trees, with nesting densities reaching 10 pairs/km2, non-breeding densities of 51 birds/km2, and... read more

Recommended citation

Kemp, A.C. & Boesman, P. (2019). Knobbed Hornbill (Rhyticeros cassidix). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 21 July 2019).