Trumpeter Hornbill

The trumpeter hornbill (Bycanistes bucinator) is a medium-sized African forest hornbill, about 50–55 cm long. Males weigh roughly 607–941 g and females about 452–670 g. The plumage is mostly black, with a white belly and rump, broad white areas under the wings and white tips to the wings and tail. Bare skin around the eyes is reddish, while the bill and casque are dark. The casque is the prominent helmet-like structure on top of the bill.

Males are larger and have a tall casque that can extend almost to the tip of the bill. Females have a smaller bill and a much shorter casque, making the sexes relatively easy to distinguish at close range.

Trumpeter hornbills are found mainly in evergreen forest, especially riverine and coastal forest, but also use deciduous woodland and montane forest up to about 2,200 m. They can cross large areas of open savanna or farmland when moving between forest patches.

The species also uses well-wooded gardens and urban areas where mature trees and fruit remain available. Large old trees are especially important because they provide both food and the natural cavities needed for nesting.

Fruit dominates the diet, especially figs, berries and other fleshy fruits. Flowers are also eaten, while animal food includes caterpillars, spiders, millipedes, wasps and occasional crabs, bird eggs and nestlings.

The birds move widely as different trees come into fruit and can change feeding areas quickly. This dependence on scattered fruiting trees helps explain their extensive daily movements.

Trumpeter hornbills are important seed dispersers because many fruits are swallowed whole and the seeds are later regurgitated or passed intact. Tracking in KwaZulu-Natal showed potential seed-dispersal distances of up to 14.5 km, allowing seeds to be carried between forest patches separated by open land.

The birds can also use mature gardens in towns as part of this wooded landscape. In Eshowe, tracked hornbills used indigenous forest most often but also regularly visited residential gardens, while cultivated land was used very little. Large trees in towns can therefore provide useful feeding habitat between natural forest areas.

Trumpeter hornbills are highly mobile and may travel many kilometres between fruiting trees and night roosts. They readily cross open savanna and agricultural land when moving between wooded areas, even though most feeding takes place in trees.

They are also conspicuously noisy. Loud nasal wails and braying, trumpet-like calls in flight often reveal birds moving between feeding areas before the flock itself becomes visible.

Trumpeter hornbills are most often seen in pairs or family groups of three to five birds, but larger flocks form where fruit is abundant. Groups of several dozen are regular, and up to around 100 birds may feed in the same general area.

Communal night roosts can be even larger. Birds may arrive from as far as about 15 km away and gather in large trees in flocks of up to around 200. At dawn the roost breaks up and the birds leave again in pairs or small groups to search for fruiting trees.

Trumpeter hornbills nest in natural tree cavities, with egg-laying in southern Africa concentrated mainly from September to January. After choosing a cavity, the female seals herself inside with material brought by the male, leaving only a narrow slit through which he passes food. She is therefore heavily dependent on her partner throughout incubation and much of the chick-rearing period.

A clutch normally contains two to four eggs. The female incubates alone for about 24 days while the male supplies food. The chicks remain in the cavity for at least another 50 days. In southern Africa the female may remain sealed inside from egg-laying until the chicks leave the nest, a period of about 94 days. The young continue to associate with their parents afterwards and may remain in the family group for several months.

The trumpeter hornbill is globally classified as Least Concern on the IUCN Red List. It has a broad range in eastern and south-central Africa and remains locally common in many suitable forests and wooded landscapes.

Forest clearance and the loss of mature trees can reduce both fruit supplies and nesting cavities. The species can cross open areas and use wooded urban environments, which helps it tolerate some forest fragmentation, but large old trees and remaining forest patches are still essential.