The Hornbill Project

Hornbills are among the most striking and endangered birds of the world. They belong to the families Bucerotidae - 52 species, and Bucorvidae - 2 species. Their name derives from their long decurved bill that often is surmounted by a casque, which further increases the size of the bill. Thirty-one species of hornbills live in Asia, 10 of which live in Myanmar and 13 of which live in nearby Thailand. Hornbills are unique in that females choose a natural cavity in a tree or rock inside where they seal themselves. While incarcerated they lay the eggs, moult the flight feathers and then rear the chicks. In many species the males deliver food to the family inside the nest throughout the nesting period while the female remains with the chicks until they fledge.

At least 3 species live in the Mergui Archipelago, the Great Hornbill being the largest (up to 150 cm) and the Oriental Pied Hornbill being the smallest (up to 90 cm). In Asia the Plain-pouched Hornbill has the most limited distribution of the three, and our researches revealed that the archipelago hosts a very important population of this rare bird that must be protected.

Great Hornbill (Buceros bicornis) male

Hornbills are mainly frugivorous birds (although their diet partly includes also small animals) that swallow the entire fruit without damaging the seeds. These are successively defecated or regurgitated far from the mother tree; hornbills are thus important seed dispersers in the forest. For this reason and for their habit of nesting in cavities on large trees that are often very priced as timber wood, the presence of hornbills in a forest is considered an indication of a healthy ecosystem.

Oriental Pied Hornbill (Anthracoceros albirostris) eating a fig

Among the researches that we conduct in the Mergui Archipelago, our ornithologists have set up a study of hornbills and their ecological requirements. Besides conducting censuses of the species on the various islands, we aim at studying their nesting habits, their diet, their use of the territory and their flocking behaviour. In regards to the latter, why do hornbills gather in large communal roosts outside the breeding season? Do they behave so in relation to food abundance and availability? Or do they flock together as a defensive strategy against predators? Or, possibly, do they find their mates among the flock during the pre-breeding season?

Observations are carried out with the help of eco-volunteers who join our expeditions as part of their study curriculum or just as a different way of spending their holiday time.

Plain-pouched Hornbill (Aceros subruficollis) male

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