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Hornbills Are Well Known As One of the Most Magnificent Bird Groups in Asian Tropical Forests. As Flagship Species, Their Presen

Hornbills Are Well Known As One of the Most Magnificent Bird Groups in Asian Tropical Forests. As Flagship Species, Their Presen

RESEARCH Research in Thailand Text by Dr. Pilai Poonswad Photos by Thailand Hornbill Project

Hornbills are well known as one of the most magnificent groups in Asian tropical forests. As flagship , their presence and status reflect the health of the forest ecosystems. Here Dr. Pilai Poonswad provides an update on the important research and conservation work going on in Thailand.

Research sites Research on in Thailand has been carried out by the Thailand Hornbill Project (THP), based at the Faculty of Science, Mahidol University, and supported by Hornbill Research Foundation (HRF) for the past twenty years. The THP has conducted ground-breaking research on the breeding biology of hornbills, including their nesting behaviour, nest characteristics, nest plaster materials, food and feeding and breeding success, with further studies continuing on home range, nutrients, influence of availability of suitable nest cavities and dispersal. Long-term monitor- ing of breeding status was conducted for four hornbill species in Moist Evergreen Forest (70 km2) at Khao Yai National Park (KYNP), six species in Hill Evergreen Forest (132 km2) and in Mixed Deciduous Forests (248 km2) at Huai Kha Khaeng Wildlife Sanctuary (HKK), and six species in Tropical Rain Forest (90 km2) at Budo-Sungai Padi National Park (BSNP). Hornbills breed once a year. The breed- ing season at KYNP and HKK is from January to May, whilst at BSNP it is from March to July. Researchers have observed 2,703 nesting-cavity years at KYNP since 1981, 1,615 at HKK since 1990, and 1,437 at BSNP since 1994.

Nesting habits When nesting, female hornbills seal themselves into a cavity of a large tree. Among 23 genera of nest trees at KYNP, the most important were Dipterocarpus and Cleistocalyx (formerly Syzygium). In HKK, major nest trees are Cleistocalyx, Tetrameles and Dipterocarpus. In BSNP, the major nest trees are Dipterocarpaceae (Hopea, Shorea and Nelobalanocarpus), but Hopea is the most important , ( rhinoceros), accounting for 40%. Nest plaster material comprises food debris, wood chips, female breaking out decayed wood and mud. The shape of nest entrances is oval or elongated, and the of nest nest cavity measures about 50 cm deep x 40 cm wide x 100+ cm long.

16 Nature Watch Oct - Dec 2009 Oct - Dec 2010 Nature Watch 17 Hornbills are unable to excavate also moved over large ranges, 4-35 km² Territories and densities non-breeding season, the range size of their own nest cavities, as do wood- depending on the species, thus enhanc- Studies of home range size for indi- the (28 km²) was peckers. But wood-decaying fungi play ing seed dispersion. Therefore, it was vidual males of three hornbill species greater than that of the key roles in development of cavities predicted that with fewer dispersal monitored using radio telemetry at (14.7 km2). In Hill Evergreen Forest at in trees. Our study done in KYNP agents, there would be less seed removal, KYNP (1998-1991) revealed that the HKK, the year round home range and (2004-2008) found that the number higher seed predation and less recruit- home range of Great Hornbill was 3.7 habitat utilization of Rufous-necked of trees with at least one cavity was ment of large-seeded plants in fragments km², White-throated Brown Hornbill Hornbills (2004-2006) was 15 km² and 15.5% in Dipterocarpus and 13.7% in than in continuous forests in southern 4.3 km² and Wreathed Hornbill 10 of Brown Hornbills was 33 km². At Cleistocalyx. Thailand. km2 in the breeding season. In the Budo Mountain, estimated mean home Of a total of 1,137 fungal isolates (i.e. isolated samples) from these tree genera, the highest number was from Dipterocarpus (565 isolates) out of a The three areas of study total of 65 species, 49 genera, 31 fami- Khao Yai National Park is situated in northeast Thailand (14º5‘-35‘ and 101°5‘-52‘E). It lies and 4 phyla that were identified. 1 covers an area of 2,168 km². Approximately 90% of forest cover (evergreen forest) are Forty species were isolated from live suitable for four species of hornbills. This is the 2008 breeding success of four hornbill Dipterocarpus, 51 from Cleistocalyx, 11 species in our study area within the park. from dead Dipterocarpus and 10 from Location Hornbill species No. existing No. No. % Success dead Cleistocalyx. nest sealed success of sealed Apart from these, there were 11 (Rhinoplax vigil), male at nest. Khao Yai Great Buceros bicornis 43 29 29 100 species (16.2%) found exclusively in 2 N.P. Dipterocarpus and 20 species (29.4%) in total. Annually, over 17 years, only 26 63 species during the breeding season Wreathed undulatus 35 16 15 94 Cleistocalyx. Four species (6.15%) were nests (86% of 31 suitable sites) were and 65 species during the non-breeding White-throated Brown 24 13 13 100 austeni found to be common among all these used and produced 19 chicks (49% season. Major food-plant families were tree species. Identified fungi involved success). After 31 nests were repaired Lauraceae, Moraceae, Annonaceae and 1 Oriental Pied 51 29 29 100 albirostris in creating the cavities were almost all over 5 years, an additional 12 chicks Meliaceae, but we suggest that delivery soft rot fungi (97%), i.e. Trichoderma were fledged annually. Average life span of protein may be linked, in Total 153 87 86 99 spp., Gliocladium spp. and Fusarium of a cavity in trees at Hill Evergreen some way, to breeding success. Huai Kha Khaeng Wildlife Sanctuary is situated in western part of Thailand (15˚00‘- spp. and a few white rot fungi (3%), i.e. Forest was 6 years, whereas in Mixed in the diet comprised 70 species belong- 35‘-15˚50‘N and 99˚00‘-99˚28‘E). It covers an area of 2,780 km². Approximately 75% of Sporotrichum spp. and Coprinus sp. Deciduous Forest it was slightly longer ing to various groups, including 2 various forest types (including monsoon evergreen, hill evergreen, mixed deciduous Natural damage to nest trees at 8 years. In Mixed Deciduous Forest, and arthropods, amphibians, reptiles, forset and secondary growth) are utilized by 6 species of hornbills. This is the 2008 breeding success of five hornbill species in our study area, no nest of Wreathed Hornbill was found. and nest cavities obviously affects the the unsuitability factors of 19 nests were mollusks, crustaceans, fishes, mammals breeding success of hornbills by reduc- sunken nest floor (41%) and narrowed and . Location Hornbill species No. existing No. No. % Success ing availability of suitable nest cavities. nest entrance (36%), while in Hill Hornbills are able to store many nest sealed success of sealed The shortage of nest cavities results in Evergreen Forest for 12 nests sunken fruits per feeding in the esophagus and HKK Great 21 18 12 67 Wildlife nest competition at KYNP, incidents of nest floor was 79%. stomach, and then regurgitate their Rufous-necked Aceros nipalensis 10 4 4 100 which were recorded for as high as 33% In Tropical Rain Forest at Budo seeds as they move, making hornbills 3 Sanctuary Plain-pouched Rhyticeros subruficollis 7 5 5 100 of the cavities available. The need for Mountain, a part of BSNP, 166 nest significant agents. nest improvement by our field staff is trees were recorded. Annually, over 15 To clarify the effect of hornbill Tickell’s Brown Anorrhinus tickelli 8 6 6 100 50% in trees of Dipterocarpus, 29% in years, 37 nests were used and produced loss on seed dispersal in tropical forests, Oriental Pied 25 21 20 95 Cleistocalyx and 21% in others. at least 29 chicks (71% success). The research was done at BSNP and Hala- Total 71 54 47 87 A nest tree is a tree with a cavity average life span of a cavity was 7 years, Bala Wildlife Sanctuary (HBWS) in Budo Mountain is a part of Budo-Sungai Padi National Park, which is situated in south- and observed hornbill activity, not all of and sunken floor was the main cause of southernmost Thailand (2005-2008). ern Thailand (101˚30‘-101˚40‘E and 6˚21‘-6˚35‘N). It covers an area of 189 km². The area is those turn out to be suitable. In KYNP, unsuitability (63%). Mahidol University Government 3 covered by tropical rainforest, but is experiencing heavy encroachment and conversion 201 nest trees were found. Annually, Fund, National Center for Genetic to fruit and Para rubber plantation. Approximately 40% of the remaining forest supports 6 spe- cies of hornbills. This is the 2008 breeding success of the six hornbill species in our study area. over 26 years and without repair, 35 Food and seed dispersal Engineering and Biotechnology nests (72% of 50 suitable trees) were Although hornbills are omnivorous, (BIOTEC) and HRF, supported the Location Hornbill species No. existing No. No. % Success used and produced an average of 42 their main diets are fruits, varying research. The results showed that horn- nest sealed success of sealed chicks. After 75 nests were repaired, between 60-95% of the total diet bills consumed at least 89 fruit species Budo Great Hornbill 51 18 16 89 over 16 years, an additional 23 chicks depending on species. Research found and tended to ignore well-protected Mountain Rhinoceros Hornbill 38 6 3 50 were fledged annually. The average life that fruits are an important source of all fruits, fruits of small trees, green-brown Buceros rhinoceros span of a cavity was about 9 years, but nutrients, especially fat, for four horn- fruits, very small fruits (<10mm in Helmeted Hornbill Rhinoplax vigil 9 1 1 100 after repair it was extended for another bill species at KYNP. Ripe fruits of 139 diameter), or very large fruits (>40mm 4 years. The main causes of unsuitability plant species, from 76 genera and 36 in diameter). Wreathed Hornbill 11 1 1 100 were sunken nest floors (50%) and nar- plant families were recorded in the diet Although hornbills had clear Bushy-crested Hornbill 11 2 2 100 rowed or closed entrances (40%). of hornbills. feeding preferences for numerous fruit Anorrhinus galeritus At HKK, 63 nest trees in Hill In the hornbill’s annual life cycle, varieties, they also seemed to be quite White- 9 0 0 0 Berenicornis comatus Evergreen Forest were located, and 148 fruit species consumed were: 22 spe- flexible in eating whatever was available Bushy-crested Hornbill (Anorrhinus galeritus) in Mixed Deciduous Forest, 211 in cies during the pre-breeding season; in the forest. Additionally, hornbills Hornbill at nesting tree. Total 129 29 23 79

18 Nature Watch Oct - Dec 2009 Oct - Dec 2010 Nature Watch 19 range of fledglings of Great Hornbills all Great Hornbill population levels in genera and 31 species of Asian hornbills (2006) was 2.1 km² and the core area three different types of forest habitats at (23 additional species in the occur was 2 km². Differences in range sizes of HKK showed significant partitioning in only). Hornbill Menu different species may relate to breeding of genetic divergence, it was postulated It was discovered that all clades strategy and differences in diet within that these three subpopulations have dif- leading to frugivorous hornbills origi- each study area. To gain more detailed ferent local adaptability for each area. nated in the mid-Eocene (~48 Millions insight into home range studies, move- At Budo, there was statistically of years ago) and this explosive radiation ment patterns and habitat utilizations significant genetic differentiation present coincided with a remarkable floral inva- of hornbills in the western and north- among and within individuals inside the sion of Asian rainforests. The invasion eastern forests, GPS Satellite Telemetry region, but not between subpopulations, commenced when the micro-continent is currently being used, with financial and this implied that these three subpop- of reached and its distinctive support from PTT Exploration and ulations in Budo were recently separated. flora colonized in two waves, one mid- Production PCL. Comparison of genetic divergence Eocene when offshore the Sunda Shelf, Through awareness of various among Great Hornbill populations in the second late Eocene on collision with ongoing threats to hornbill populations, three geographic regions (HKK, KYNP the Asian mainland. including , poaching and Budo) showed high significant genet- In modern rain forests, most flow- and felling of potential nest trees, a five- ic differentiation. Great Hornbill popula- ering-plant species produce fleshy fruits year grant (2004-2008) from BIOTEC tions of KYNP and HKK showed the and have their seeds, many of which are was received. It was for a study of the least genetic divergence, with the largest large, dispersed primarily by vertebrates. species diversity, genetic variation and divergence observed between populations Trees in the proto-Indian forests had population sizes across the fragmented of KYNP and Budo. These genetic diver- similar large seeds and each wave of forest landscape in 12 forest complexes, gences corresponded well to the isolation the Indian floral invasion would have with intensive study in three main by distance between those regions. required agents with different seed dis- sites from different geographic regions, Phylogenetic relationship among persal abilities, the first for long-distance including the Western Forest Complex 13 hornbill species in Thailand was overwater dispersal, the second includ- (WEFCOM), KYNP and BSNP, all, determined using the mitochondrial ing short-distance terrestrial dispersal. important habitats for hornbills. DNA sequences of the complete cyto- Hornbills, together with Old Population density of four species chrome b gene and a D-loop region. World fruit pigeons and fruit bats, were in Mixed Evergreen Forest at KYNP The phylogenetic trees indicated available at the time for the first wave, (1,965 km²) was estimated at 32 indi- that the genus Rhinoplax (Helmeted while smaller and/or less mobile taxa viduals/km² and for 6 species in Mixed Hornbill), a member of the large- only became available or relevant for the Evergreen Forest, Mixed Deciduous casqued hornbill group, is most closely second wave. The rapid colonization of Forest, Hill Evergreen Forest and Dry related to the hornbills of genus Buceros the Asian flora seems improbable unless Dipterocarp Forests at HKK (2,697 (Great and Rhinoceros Hornbills). assisted by frugivorous vertebrates, such km²) was estimated at 42 individu- Therefore, Helmeted Hornbill is as hornbills. als/km². In the Tropical Rain Forest at presumed to be the oldest or immedi- BSNP (189 km²), the estimated popula- ate ancestor of Great and Rhinoceros Habitat requirements tion was highest at 47 individuals/km². Hornbills. Conversely, the White- Remote sensing and GIS were used to The differences in densities of hornbills crowned Hornbill (Berenicornis), an inter- compare changes in hornbill habitats between these study sites may be due to mediate-casqued hornbill, was shown (1985-2000). The results showed that differences in the area, type and perhaps by the analysis to be more related to at core areas of WEFCOM, the former the quality of these forests. Buceros than any of the other species. For agricultural areas were reduced by 1% the small-casqued hornbills of Rhyticeros per year after the village relocation con- Population studies genus, Wreathed Hornbill (R. undulatus) ducted by the government during the The genetic variation and differentiation and Plain-pouched Hornbill (R. subru- late 1990s allowed the forest to recover. of Great Hornbill populations living ficollis) are in the same clade, indicating This resulted in a 0.02 % per year using an MaxEnt Model, revealed that within these various forest communities. require for nesting could be found. in three forest habitats (HKK, KYNP closely related hornbills of similar shape increase of forest area. only 8% of forest areas in Thailand are The forest sites differed significantly in The combination of a lower per- and BSNP), which differ in patch size, and color of their casques. This group The same trend occurred in KYNP being occupied by hornbills. their structure and tree species diversity, centage of potential nest trees and the habitat integrity and disturbance were of hornbills has Rufous-necked Hornbill but, in contrast, at Budo, agricultural This habitat modeling at a finer as well as in their relative number of predominance of a relatively small group compared. Microsatellite DNA markers (Aceros nipalensis) as their common areas increased 6% per year and the forest scale was done for a single species as potential food and nest trees. of food tree species in montane and dry from Great Hornbills were applied as a immediate ancestor or, in other words, area decreased by 5% per year, showing well, the Rufous-necked Hornbill in Trees of known hornbill food spe- evergreen forest could render such habi- tool to track desirable traits. Thirteen Rufous-necked Hornbill is a living ances- an alarming situation for the future of WEFCOM. These models predicted cies were at relatively high densities at tats less capable of supporting hornbill polymorphic microsatellite markers were tor to hornbills of this linage. hornbills at Budo Mountain. The results that the distributions of all hornbill all sites, but they differed in the relative populations compared to lowland dipte- isolated and characterized. To understand the origin from a distribution model of 9 hornbill species, except for the Oriental Pied contribution of a few key species and rocarp and moist evergreen forests. The results indicated that Great and radiation of Asian hornbills species (except species with insufficient Hornbill, were affected by the patch size families. Although big trees were found The study suggests that detailed Hornbill populations of KYNP showed (), a dated phylogeny data, including Bushy-crested, Wrinkled, of the forest habitat. at comparable densities across sites, nei- information on hornbill food and nest no significant genetic differentiation at of hornbills using mitochondrial DNA and Plain-pouched Hornbills; and also Further, we characterized six dif- ther big-tree species diversity nor den- tree species will be required to optimize all hierarchical levels and therefore were sequences of the cytochrome b gene was excluding the common Oriental Pied ferent forests that are home to hornbill sity could accurately gauge the number the management of hornbill conserva- considered as a single population. Since compiled. The study included all 15 Hornbill that occurs in many places), populations, to identify habitat traits of trees in which cavities that hornbills tion areas, as opposed to a quick evalu-

20 Nature Watch Oct - Dec 2009 Oct - Dec 2010 Nature Watch 21 About Dr. Pilai Poonswad

Pilai Poonswad has an M.Sc. in Microbiology from Mahidol University and a Ph.D. in Avian Ecology from Osaka City University, . Her field of expertise is Avian Parasitology and Avian Biology and Ecology. She is the representa- tive of Thailand in the International Ornithological Committee, a This Great Hornbill (Buceros bicornis) has The field staff who makes it all possible. taken to an artificial nesting box. founder and committee member ation of forest structure and diversity. Wreathed Hornbills) checked the nests, Education Ministry and Tourism of Hornbill Research Foundation Moreover, the identification and conser- but none was used. Authority of Thailand can use and apply and elected as Honorary Fellow of vation of core areas for optimal hornbill In 2006, three species (Great, the information from each level of suc- American Ornithologists’ Union. She feeding and nesting habitats will be a Rhinoceros and Helmeted Hornbills) cess, including our techniques, databases HONORS useful initiative for the continued pres- came to artificial nests and a Great and publications, for the proper man- is currently Professor of Biology at ence of these majestic birds in Asian Hornbill was found in one with a agement of and for recovery plans in the Department of Microbiology, 2009 • Recipient of 2008 Distinguished alumni from forests. chick. In 2007, two species (Great and degraded and/ or logged forests. Graduate Studies of Mahidol University Rhinoceros Hornbills) investigated nests Faculty of Science, Mahidol 2008 • Recipient of 2007 The Dushdi Mala Medal for Great Adopt a hornbill’s nest and two pairs of Great Hornbills occupied University, Bangkok, Thailand. Lately Nevertheless, the loss of forest area is nest boxes. In 2008, the same two species Hornbill Adoption Eminence in Science, awarded by His Majesty King she has received numerous honors Bhumibhol (King Rama IX) not the only factor affecting hornbill investigated nests and three pairs of Great Year Total survival, since poaching and illegal log- Hornbills imprisoned themselves. And and awards for her scientific work 2007 • Recipient of 2006 Outstanding Lecturer Award ging also are important factors. BSNP, in 2009, the same two species checked Supporters No. of nests adopted and contribution to conservation. (Science & Technology) from the Council of the one of the main study sites in southern- the nests and five Great Hornbills sealed most Thailand, had experienced heavy themselves into nest boxes. 1998 59 72 University Faculty Senates of Thailand 1999 69 106 poaching. The success of the nest adoption • Recipient of 2007 National Outstanding Person An intensive campaign was started program has led to a second phase, the 2000 93 119 Award (Natural Resources and environment) from in 1994. Over 40 villagers (former establishment of the Budo Hornbill 2001 83 109 Prime Minister Office, The Royal Thai Government poachers/illegal loggers) from 13 villages Conservation & Education Center in 2002 92 128 around Budo Mountain participated 2004 on a piece of land donated by a • Recipient of BCST-Swarovski Award 2007 2003 93 148 in our research and conservation pro- villager’s family. The Center provides (Outstanding Bird Conservationist) from Bird 2004 103 183 grammes. Urban people could also take educational and conservation lessons for Conservation Society of Thailand & Swarovski Optik, part through such schemes as hornbill approximately 400 individuals per year 2005 109 206 Austria nest adoption, with 1,622 nest-years of to schoolteachers, children, teenagers 2006 124 223 adoption to date. The program is now and villagers in the surrounding area. 2007 106 174 2006 • The first Thai Laureate of The 2006 Rolex Awards for considered successful in terms of poach- Aside from these programs, we are 2008 89 171 Enterprise from Rolex SA, Switzerland ing eradication and dissemination of expanding the channel for communica- the hornbill conservation message to tion between persons or groups with an • The first Thai recipient of The 52nd Annual Chevron the public. Since 1994, villagers have interest in hornbills through a Hornbill Anyone who adopts a hornbill Conservation Awards from Chevron Corporation, observed and guarded for 1,303 nest Network. Presently, 18 local schools sur- nest does not only make in important USA cavity-years and, for these, there has rounding Budo Mountain are members contribution to nature conservation. been 70% breeding success and over of the Network. Our conservation pro- He/She will also receive a full report of • Recipient of 2006 Faculty of Science Outstanding 400 chicks have fledged. grams show clear, progressive develop- events at the end of the nesting cycle Lecturer Award (Professor level) from Faculty Senate In our attempt to increase the ment of relationships among urban, rural together with photographs of his/her of Faculty of Science, Mahidol University, Bangkok, breeding population of Budo Mountain, and natural environments, using hornbills birds. A visit to the nest during breeding Thailand the number of suitable nesting sites were as a tool. Consequently, hornbills are can sometimes be arranged at own cost. • Recipient of 2005 Mahidol University Prize for increased by providing artificial nests. being conserved in a sustainable manner. Please go to http://www.sc.mahidol. Nineteen artificial nests were installed at Academic and government insti- ac.th/research/hornbill.htm and find Excellence in Research from Mahidol University, Budo Mountain in 2005 and four spe- tutes, e.g. the National Park, Wildlife, the link to the Adoption Program at the Bangkok, Thailand cies (Great, Rhinoceros, Helmeted and Plant Conservation Department, bottom of the page.

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