ศาสตร์เกษตรดินปุ๋ย : ขอบคุณแหล่งข้อมูล : หนังสือพิมพ์ The Nation
Almost extinct in Indonesia and Malaysia, the Helmeted Hornbill is still thriving in Thailand’s south, but for how long?
THE ICONIC helmeted hornbill (rhinoplax vigil), one of the most gigantic and spectacular of Asia’s 30 species of hornbills, is in grave danger of extinction according to BirdLife International and the International Union for Conservation of Nature (IUCN) who upgraded its threat status to critically endangered last November.
All hornbills are charismatic, mainly frugivorous (fruit-eating) forest birds of tropical forests, who take their name from the large ornamental casques on their bills, which differ in size and shape among species. The helmeted hornbill (known as Nok Chon Hin in Thai) is special, though, because unlike the other hornbills, the casque is not hollow but solid and bony.
Casques of the helmeted hornbill have long been sought after by Chinese craftsmen, who carve this so-called “hornbill ivory” or “red ivory” into elaborate ornaments and snuff-boxes. Even as long as 2,000 years ago native peoples of Borneo were already fashioning helmeted hornbill casques into ear-pendants and toggles. But Japan and China are the major consumers of helmeted hornbills casques, demand for which has suddenly and inexplicably escalated, threatening the future of this unique species.
“In 2013 about 500 adult helmeted hornbills were killed each month, or some 6,000 birds in one year, and that was only in West Kalimantan,” laments Yokyok Hadiprakarsa of the Indonesian Hornbill Conservation Society.
According to Hadiprakarsa, who also works with the Wildlife Conservation Society (WCS) in West Kalimantan, and who has interviewed many villagers, foresters and officials, only 1,111 helmeted hornbill heads were confiscated by the Indonesian authorities between 2012-2014, and eight Chinese traders, along with two Indonesian citizens, arrested.
The helmeted hornbill heads were being smuggled to major ports in Sumatra, Java and onwards to Hong Kong and Taiwan.
Such a high level of exploitation is clearly unsustainable and, if left unchecked, will quickly drive remaining helmeted hornbill populations to extinction.
Dr Nigel J Collar of BirdLife International is an expert on these larger hornbills, noting that they have specific nesting requirements, choosing the largest living trees with nest holes topped with a perch for the male to use while provisioning the female.
During the breeding cycle, the female remains incarcerated in the nest cavity for 160 days, when both she and the nestling are dependent solely on food delivered by the male. Hunting during the breeding season therefore has an especially severe impact, causing the death of the nestling and compromising the survival of the female too.
Rates of forest loss in the Sundaic lowlands of Malaysia and Indonesia remain extremely high, owing partly to the escalation of illegal logging and conversion of forest land to rubber and oil-palm. Such habitat loss has already caused a massive reduction in hornbill numbers. Even inside protected areas, the best remaining stands of valuable timber may be targeted for logging.
Forest fires have also had a damaging effect.The helmeted hornbill has apparently almost disappeared from habitats where it was previously abundant in Sumatra, Indonesia, and is equally threatened in both the Indonesian and Malaysian parts of Borneo. It is still widespread in protected areas in Thailand’s southern provinces, which together support six of the country’s 13 species including the helmeted hornbill.
But even here populations of the helmeted hornbill are small and fragmented as so little of their ancestral forest habitat remains as national park and wildlife sanctuary, and all hornbills remain vulnerable to hunting, and theft of chicks for the illegal pet trade.
The Hornbill Research Foundation of Mahidol University, Thailand, led by Prof Pilai Poonswad and her team, has done much to raise the profile of hornbills in this country, conducting long-term term ecological studies
while monitoring populations of all hornbills in Thailand since 1978.
The foundation has studied the breeding ecology of the helmeted hornbill at Budo-Sungai Padi National Park and worked with villagers in the provinces of Pattani, Yala and Narathiwat to organise a Hornbill Family Adoption Programme, under which for US$150 (Bt5,250) per year the same villagers who formerly collected hornbill chicks are employed instead as nest-guardians.
Records sent to Bird Conservation Society of Thailand (BCST), the Thai partner of BirdLife International, by birdwatchers over the past few decades show that helmeted hornbills survive today only in the largest areas already protected as National Parks or Wildlife Sanctuaries.
It will take all the resources of the government’s Department of National Parks, Wildlife and Plants Conservation (DNP) to keep these safe from poachers. A Helmeted Hornbill Task Force established through international cooperation among SE Asian BirdLife Partners – BCST-Birdlife Thailand; the Biodiversity and Nature Conservation Association of Myanmar; the Malaysian Nature Society, Nature Society (Singapore) and Burung Indonesia – to alert, and provide technical support for, government agencies in their respective countries could help coordinate action to safeguard helmeted hornbill.
Because of its relatively advanced capacity and knowledge, and good public awareness, Thailand is perhaps well placed to lead the way with its own a national action plan for the helmeted hornbill. The key government agencies, besides DNP, include the Customs Department, the Thai secretariat of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (Cites) and the Office of Natural Resources and Environmental Policy and Planning (Onep).
With timely and appropriate action, there is every hope that Thai populations of the helmeted hornbill in southern Thailand will not follow the Gurneys Pitta into extinction, but will be sustained, and even recover, as have populations of some other endangered vertebrates, such as gaur and banteng in a few, favoured protected areas of the western forest complex.
A DISAPPEARING FOREST GIANT
– The Helmeted hornbill is among the largest of Asian hornbills, about 110-120 cm long with a wingspan up to 2 metres Its plumage is patterned blackish- brown and white, with elongate white central tail feathers bearing a black band. The skin of the bare neck is red in the male, and pale turquoise in the female Its distinctive high red casque, yellow at the front and weighing about 300g, is the “helmet” of the common name.
– Helmeted hornbills are confined to lowland forests, from southern Myanmar, southern Thailand, Malaysia, Singapore, Brunei and Indonesia – the Sunda Region. They inhabit mature evergreen lowland forest, and though recorded up to 1,500 metres above sea level, are mostly confined to lower elevations.
– The call of helmeted hornbill is utterly unique -once heard never forgotten. It is a series of loud, intermittent barbet-like hoots, sometimes double-toned and over two dozen in number, which gradually accelerates to culminate in a cackle reminiscent of laughter. Its unique casque is used in rarely seen aerial jousts in which two male birds fly from a treetop in opposite directions, circle round and swoop at each other, cracking their casques together in mid-air in a spectacular contest for supremacy.
– Hornbills are important bio-indicators of good quality forest and, indeed, help maintain plant diversity and forest cover through their role as seed dispersers. They are the largest fruit-eating birds in the forest canopy, consuming the fruits of more than 200 tree species, including not only figs but lipid-rich fruits, regurgitating and defecating their seeds far and wide, at great distances from the parent tree. Their role in maintaining the forest ecosystem is so immense that they are regarded as farmers of the forest and one hornbill may plant more than 500,000 trees in its lifetime. They are also predators of small animals including squirrels, snakes, and other birds including even the chicks of their own or other hornbill species, and can live more than 30 years.