The helmeted hornbill is thought to be a territorial bird. Small groups of up to 14 non-breeding and immature birds may forage for food within a single area, but adult breeding pairs have their own territories (2).
The helmeted hornbill performs incredible displays in flight, in which individuals collide in mid-air, their casques clashing with a loud ‘clack’. This aerial jousting, which usually takes place between two males, often results in one or both hornbills being flung backwards, before righting themselves again in flight. These collisions are typically observed near fruiting fig trees, suggesting that the birds are fighting over access to their favoured food (5).
The main food of the helmeted hornbill is fruit, with figs being a particular favourite. However, this species also feeds on small animals, including mammals, snakes, and even smaller hornbills. It typically forages high up in the forest canopy, where it can sometimes be seen hanging upside-down, digging under the bark with its heavy beak and casque. Although breeding pairs share a territory, the male and female forage independently (2).
All hornbills are noted for their bizarre nesting habits, in which the female is sealed within a hollow tree to incubate the eggs (2). A nest is created within a natural hollow, high in a tree, and the female is then sealed within the hollow with mud by the male (2) (3). Only a small hole is left, through which the male passes the female regurgitated food, while the female incubates the eggs (2). The helmeted hornbill has been observed to lay eggs in January to March, as well as in May and November (2). When the young have hatched, the female breaks out of the hollow, then reseals the entrance until the young have fledged (3).