Which hornbill species, with its distinctive solid ivory-coloured casque and black-and-white plumage, is the national bird of Sarawak and a symbol deeply embedded in Iban culture?

• A Great hornbill
• B Helmeted hornbill
• C Wreathed hornbill
• D Rhinoceros hornbill ✓

The rhinoceros hornbill (Buceros rhinoceros) features prominently in Iban mythology and rituals; its large golden-yellow casque and resonant call make it unmistakable in Borneo's forests.