The Great Hornbill is a noisy example of conservation success in Asia. The birds and duckbill dinosaurs have sound-amplifying casques, and who knows, the hornbills’ RROH call may be similar to a Hadrosaurid’s.
By Rex Graham
To keep the croaking sound of the Great Hornbill echoing through some of the world’s most primeval forests, researchers are using a wide range of tactics, including nest boxes the size of refrigerators.
Great Hornbill diet
In Thailand, scientists are renovating unwanted natural cavities as “fixer uppers.” The scientists fill holes and cracks in the trees, and reduce the entry of rainwater into the cavities in hopes of attracting picky parents.
The most innovative approach is a $120 payment to local residents in India who look after a hornbill family and its nest site for 1 year. Even former hornbill poachers have been recruited as part of the “Hornbill Family Adoption Program.” Local residents have increased their incomes from guiding visitors, including the bird lovers who had donated the money to the adoption program.
Great Hornbills are still relatively easy to find in the forests of south Asia and nearby islands. They eat dozens of species of figs and other fruit, which make up over half their diet. They also eat snakes, squirrels, horned lizards, beetles, centipedes, cicadas and other creatures.
One of their biggest challenges is finding a suitable tree cavity for a nest. More hornbills nest in unlogged forests that logged ones. And the best forests have dense stands of many large trees, which provide plenty of nest cavities. In this case, we’re not talking about woodpecker holes. Hornbills need elongated nest entrances with openings large enough to accommodate an adult female’s 3-kg body.
Such 5-star accommodations are used by Great Hornbills March through July – usually the driest months – when they nest and raise chicks.
A good supply of nest cavities for Hornbills, and hence hornbill chicks, can be an important economic factor to rural communities eager to attract birding eco-tourists.
To help Great Hornbills and encourage more birders to visit, some communities have teamed with conservationists and researchers. They are trying to reduce human disturbances of hornbills, stop forest clearing and eradicate poaching and illegal logging. With those efforts in place, researchers also are trying new kinds of nest-boxes for hornbills where there are too few natural tree cavities.
Hornbill nest box woes
You can fit 30 Eastern Bluebird nest boxes inside a Great Hornbill nest box. However, hornbills have mostly turned their massive bills the other way. Other species of hornbills use nest-boxes in the wild, but only 1 pair of Great Hornbills has settled into one after the pair looked at it for 3 seasons.
All hornbills will use nest-boxes in captivity, but in the wild they prefer the real thing. The primary takers of Great Hornbill nest-boxes have been Civet Cats and less choosy birds.
In Thailand, the tree-cavity fixer-uppers must have openings low enough “to easily allow the incubating female and later the small young to be fed through the slit opening and also to permit without difficulty the nest occupants to elevate their cloacae and defecate through the slit,” researchers with the Western Ghats Hornbill Foundation and the University of Arkansas in Fayetteville said in The Raffles Bulletin of Zoology.
Poachers protecting nests
The reproduction rate of Great Hornbills has been hurt by poachers as much as by logging. In Thailand, researchers hunted the poachers to try to explain to them why hornbill protections are so important.
“We also collected information about how they earned their living and how much income they generated from hornbills,” Thai researchers said in the journal Biological Conservation. “We invited them to direct their field skills into hornbill research and conservation.”
The Nature Conservation Foundation also implemented the $120-a-year “Hornbill Family Adoption Program,” which has enabled local participants to increase their income by guiding visitors, including bird lovers who had donated adoption money.