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Conservation of Hornbills in Thailand

  • Faculty of Science, Mahidol University

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CONSERVATION ISSUES IN THAILAND Over the past century, the natural resources of Thai-land have been depleted continuously and rapidly, driven by such pressures as population growth, poverty, and globalization, including economic expansion that places overriding importance on the size of the coun-try ' s gross domestic product. By 1985, the government had set a national forest policy target whereby no less than 40% of the country ' s area was to be protected, 15% as conservation forests and 25% as economic forests (RFD, 1985). In the Seventh National Economic and Social Development Plan (1993–1996), the target for conservation of national forest was changed to 25% for conservation forest and 15% for economic forest (NESDB, 2008), still a total of 40% of the total area. By 1989, however, only 28% of the total land area remained forested. To sustain Thailand ' s exceptional species diversity, the government has put a major effort into protecting the forest and its animal inhabitants by various conser-vation measures. Wild animals and their habitats are now completely protected by the National Park Acts (1961) and the revised Wild Animals Reservation and Protection Act (1992). A total of 123 national parks and 58 wildlife sanctuaries have been established in the
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Conservation of Hornbills in
Pilai Poonswad 1 , Vijak Chimchome 2 , Narong Mahannop and Sittichai Mudsri 3
1 Department of Microbiology , Faculty of Science, Mahidol University , Bangkok , Thailand
2 Department of Forest Biology , Faculty of Forestry, Kasetsart University , Bangkok , Thailand
3 Department of National Park s , Wildlife and Plant Conservation , Bangkok , Thailand
Over the past century, the natural resources of Thai-
land have been depleted continuously and rapidly,
driven by such pressures as population growth, poverty,
and globalization, including economic expansion that
places overriding importance on the size of the coun-
try s gross domestic product. By 1985, the government
had set a national forest policy target whereby no less
than 40% of the country s area was to be protected,
15% as conservation forests and 25% as economic
forests ( RFD, 1985 ). In the Seventh National Economic
and Social Development Plan (1993–1996), the target
for conservation of national forest was changed to 25%
for conservation forest and 15% for economic forest
( NESDB, 2008 ), still a total of 40% of the total area.
By 1989, however, only 28% of the total land area
remained forested.
To sustain Thailand s exceptional species diversity,
the government has put a major ef fort into protecting
the forest and its animal inhabitants by various conser-
vation measures. Wild animals and their habitats are
now completely protected by the National Park Acts
(1961) and the revised Wild Animals Reservation and
Protection Act (1992). A total of 123 national parks
and 58 wildlife sanctuaries have been established in the
In Thailand, as in other developing countries in Asia,
the state of conservation has not kept pace with devel-
opment. The management of natural resources is the
responsibility of several government agencies, but they
are often in confl ict. Partly in consequence of this divi-
sion of responsibility, Thailand has lost more than 40%
of its forested areas, which are the richest terrestrial
habitats in biodiversity within the past fi ve decades
(1961–2010), partly because of poor coordination
between and execution of policies in the areas of eco-
nomic, social, and political development ( FAO, 2010 ).
In 1951, Dr Boonsong Lekagul and his colleagues
founded the Association for Conservation of Wildlife,
the fi rst non-governmental organization established in
Thailand for conservation. Through its immense strug-
gle to attract attention from the government, this
group helped to establish laws concerning the conser-
vation of wildlife and their habitats, including the Wild
Animals Reservation and Protection Act (1960) and
the National Park Act (1961). For his efforts, Dr Boon-
song was named “Father of Conservation” in Thailand.
The protection and conservation of natural resources
in Thailand really only began with the formation of the
Association in 1951.
Conservation Biology: Voices from the Tropics, First Edition. Navjot S. Sodhi, Luke Gibson, and Peter H. Raven.
© 2013 John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd.
158 Conservation Biology
and intrinsic value of these ancient birds and the
threats they are facing.
Hornbills originated at least 50 million years ago in
the Eocene Period. The living species are unique and
attractive birds, not only in their appearance but also
in their intriguing nesting habits. Thai hornbills are
very large (body mass 680–3,400 g) and very noisy,
which makes them conspicuous in the forest. Although
the birds are omnivorous, fruits are the main compo-
nent in their diet ( Poonswad, Tsuji and Jirawatkavi,
2004 ); therefore, hornbills are characterized as large
frugivorous birds. To satisfy their needs, they require
intact primary forest that provides suitable nest sites
and suffi cient food resources.
Hornbills have intimate relationships with forest
plants as food, and probably coevolved with many of
these plants as seed-dispersal agents of primary impor-
tance. In ecological terms, hornbills are often consid-
ered “keystone” species whose essential service is to
move seeds away from parent trees and spread them
over a larger area. By doing this they help to regenerate
the forest and maintain the diversity of plants within
their habitat. Past studies have shown the signifi cance
of hornbills in dispersing seeds, particularly of those
plants with large seeds ( > 25 mm) that rely almost
entirely on the large bills of hornbills. By combining
existing information on their home range, number of
fruit species consumed, and their habits of regurgitat-
ing a few seeds while perching and in fl ight, some esti-
mates are possible. Great Hornbills ( Buceros bicornis )
move seeds around their home range of 30 km
2 and
over a distance of 15 km daily, while Wreathed Hornbill
( Rhyticeros undulatus ) move around over 35 km
2 ( Poon-
swad and Tsuji, 1994 ). Hornbills are undoubtedly
important in forest regeneration, particularly to estab-
lish connections between forest patches along their
yways or within their nomadic range ( Holbrook,
Smith and Hardesty, 2002 ; Kinnaird and O ’ Brien,
2007 ). It is no exaggeration that Kinnaird and O Brien
( 2007 ) name hornbills as “farmers of the forest.”
Since hornbills rely entirely on the availability of
natural tree cavities for reproduction and depend very
much on fruit as their food resource, any loss of habitat
means loss not only of breeding sites but also of food
resources. Because of their rigid requirement for breed-
past 50 years, but they cover only 15% of the country s
area, still well short of the goals stated through the
years. Thailand has also ratifi ed some international
conventions related to natural resource conservation
and management, including the Convention on the
International Trade in Endangered Species of Wild
Fauna and Flora (CITES) in 1983 and the Convention
on Biological Diversity (CBD) in 2003 ( ICEM, 2003 ).
All of these treaties support wildlife conservation not
only in Thailand but also in trans-boundary areas and
at a global scale. However, despite the existence of good
laws, enforcement mechanisms do not always seem to
work, so that there is often further depletion of primary
forest. In an evaluation of forest resources in 2004,
only about 18% out of the target of 25% of total land
areas were protected ( Trisurat, 2007 ).
The protected areas in Thailand are highly frag-
mented, but they can be grouped into 19 complexes
that include 17 forest areas and two marine and coastal
habitats. To connect these fragmented areas, a Biodi-
versity Conservation Corridors Initiative (BCI; Phase 1:
2006 –2008) was set up, with a pilot project, “Wildlife
and its Habitat Assessment in the Corridor Zone in the
Tenasserim Western Forest Complex (WEFCOM), Thai-
land” run by the Wildlife Conservation Society (Thai-
land). Seven landscape-wide species, including tiger,
elephant, gaur, sambar deer, barking deer, serow, and
great hornbill, were monitored in the complex. In
Phase II (2009–2011), the Department of National
Parks, Wildlife and Plant Conservation has raised the
corridor program to the national level so as to evaluate
and prioritize potential areas for connectivity within
and between complexes. This program will be not only
a response to the CBD, but will also serve the goal
of reducing biodiversity loss from its 2000 level, as
declared by the World Biodiversity Summit 2002 in
Johannesburg, South Africa. Although the poaching
of wildlife and collection of wild plants for illegal trade
violate both national and international laws, the cost
of this trade is still severe: between 2005 and 2008, it
was estimated at more than US$1 million.
This question is the one asked most frequently by
people living in concrete habitats! The answer to this
question is not easy, but it is challenging to help people
living in cities, who are familiar only with pigeons,
sparrows, and crows, to understand the uniqueness
Asia: Conservation of Hornbills in Thailand 159
ing sites, hornbills are inevitably threatened by any
human activities within forests, besides such natural
phenomena as storm and decomposition processes that
are also considered important threats to hornbill popu-
lations (Table 19.1 ).
Human activities have altered the environment of
other vertebrate species to an immense degree. Popula-
tion growth coupled with rapid economic growth is
profoundly important as a driver in the exploitation of
natural resources, particularly forest resources. Unlim-
ited demand, poor planning, and unsustainable use of
this valuable and natural capital resource have resulted
in a great depletion of forest resources and hence of
hornbill habitat. The depletion of forest resources
results from a range of activities, the most obvious of
which are now discussed.
Deforestation and l ogging
Deforestation poses the most serious threat to horn-
bills. The 13 species of hornbills that occur in Thailand
inhabit various types of forests, the most important
being evergreen forest, which ranges from lowland
plains up to 1500 m above sea level and which exists as
dry evergreen, semi-evergreen ( Santisuk, 2007 ;
Corlett, 2009 ), and hill evergreen forest subtypes. Ever-
green forests dominate the forested area in Thailand
(43%) but are also the most threatened forest type. Cul-
tivation is the major human activity altering these
forests, which destroys primary forest in Thailand at an
estimated rate of 0.7% annually ( FAO, 2005 ). The most
obvious consequence of evergreen forest destruction is
the loss of dominant large trees, particularly trees in
the genera Dipterocarpus , Hopea and Shorea (Dipterocar-
paceae). Losses of primary forests have impacts on
hornbill populations by reducing their potential breed-
ing sites and depleting their food resources. Diptero-
carp trees are the predominant hornbill nest trees,
accounting for 40% of nest sites ( Poonswad, 1995 ).
Deforestation has already extirpated three sympatric
hornbill species, the Great, Wreathed and Rufous-
necked Aceros nipalensis Hornbills from parts of their
range in northern Thailand ( Poonswad, 1993 ).
Hunting is another major threat to wildlife, including
hornbills. Although hornbills are canopy-living species,
their large size and noisy behavior make them con-
spicuous so that they make an easy target for hunters.
Even their secretive nesting behavior cannot elude
hunters. The purposes for hunting hornbills include for
food and the pet trade. Hunting them depends on the
existence of areas where laws are not effective, with the
hunting often linked to tribes and villagers who live in
or near the forest. Hill tribes in northern and western
Table 19.1 Nest cavity information (a) and chick production (b) at Khao Yai National Park (KY) and Budo Mountain
(Budo), with national status of hornbill species
KY (1981–2008) Budo (1994–2008)
Total Annual Total Annual
No. recorded nest trees 226 8.7 188 12.5
No. nest loss 95 4.1 44 2.9
% nest loss 42.0 4.9 23.4 2.7
No. bad cavities 123 5.1 25 1.7
% bad cavities 54.4 6.2 10.6 13.6
No. repair/improved
77 4.7 20 –
No. cavities available 120 70.8 119 90.3
(Continued )
160 Conservation Biology
Table 19.1 (Continued)
KY (1994–2008) Budo (1994–2008)
Total Annual From repair Total Annual From repair
Great Hornbill (near threatened) **
No. sealed 312 20.8 134 263 17.5
% success 77.9 78.4 42.9 83.6 84.2
No. chicks (x1/pair) 243 16.2 134 220 14.6
Rhinoceros Hornbill
(endangered) **
No. sealed 158 10.5
% success 72.8 71.8
No. chicks (x1/pair) 115 7.7
Helmeted Hornbill (endangered) **
No. sealed 43 2.8
% success 75 82.1
No. chicks (x1/pair) 32 2.3
Wreathed Hornbill (near
threatened) **
No. sealed 148 9.9 56 55 4.2
% success 89.7 87.9 33.6 73.5 72.2
No. chicks (x1/pair) 133 8.9 49 40 3.0
Brown Hornbill (Vulnerable) **
No. sealed 119 7.9 36
% success 90.6 87.3 27.4
No. chicks (x2.3/pair) * 248 16.6 74
Bushy-crested Hornbill (near
threatened) **
No. sealed 35 2.5
% success 65.5 67.9
No. chicks (x2.3/pair) * – 53 3.5
White-crowned Hornbill
(endangered) **
No. sealed 12 1.7
% success 80
No. chicks (x1.5/pair) * – 15 1.4
Oriental Pied Hornbill (not
determined) **
No. sealed 371 24.7 53
% success 92.2 91.8 12.4
No. chicks (x1.5/pair) * 513 34.2 69
All species
No. sealed 950 63.3 312 566 37.7
% success 86.9 86.5 27.6 77.8 77.8
No. chicks 1,137 75.8 326 440 29.3
* Average number of chicks per breeding pair derived from Poonswad ( 1993 )
** National status from Sanguansombat ( 2005 ) and ONEP ( 2007 )
Source: (a and b) Based on data from Poonswad (1993) Sanguansombat (2005) and ONEP (2007).
Asia: Conservation of Hornbills in Thailand 161
species are required to ascertain the actual status,
density, and potential of the remaining habitats for
target species. Twelve out of 19 protected area com-
plexes have potential as hornbill habitats. The remain-
ing seven complexes are too small and severely
fragmented, and no hornbills have been recorded in
them for the past two decades ( Poonswad, 1993 ).
Intensive surveys using point-count transects in three
complexes of different sizes in which extensive research
and conservation activities are continuously con-
ducted (WEFCOM, Dong Phayayen-Khao Yai, and
Hala-Bala) indicate that these complexes still support
viable populations of Great, Wreathed, Rufous-necked,
Rhinoceros and Oriental-Pied Hornbills, while other
species do not have adequate data for analysis (Thai-
land Hornbill Project, unpublished data; see also Table
19.1 ). Increasing connectivity of suitable habitat between
and within complexes to facilitate hornbill movement,
as being practiced for conservation planning in
WEFCOM, is a promising approach to maintain popu-
lation viability of hornbills ( Trisurat et al ., 2010 ).
The degree of threats mentioned earlier may differ
by area or region. The goal of the conservation efforts
is to increase hornbill populations to minimum viable
sizes and so sustain them for long-term survival. To
achieve this goal, clear identifi cation of threats or prob-
lems in each area or region is very important in order
to implement the most suitable strategy. According to
our knowledge and experience, we recommend our two
most successful strategies: research- and community-
based conservation.
Research- b ased c onservation
Initiation of h ornbill r esearch p roject
Some 30 years ago, knowledge on the biology of Thai
hornbills was limited to general information on distri-
bution, habitat, and anecdotes about food and behavior
( Lekagul and Cronin, 1974 ). Given the very large size
of the birds, one could imagine the magnitude of
requirements – they need large nest cavities and large
amounts of food. But, how large must the cavities be?
Being secondary-cavity nesters that are unable to exca-
vate their own nests, hornbills do not have much
choice. Finding a suitable cavity is a principal factor
that limits hornbill reproduction, but what attracts
them in seeking out a nest cavity? Ground-breaking
research to reveal the basic requirements of four
Thailand hunt hornbills mainly for food, and this
hunting might have an important impact on the resil-
ience of certain species, such as Tickell s Brown Horn-
bill ( Ptilolaemus tickelli ), particularly when the hunting
pressure is exacerbated locally by deforestation.
Evaluation and revision of the conservation status of
Thai fl ora and fauna by various criteria have been
made in the past few decades. Lekagul and Round
( 1991 ) determined the status of Thai birds based on
abundance and habitat restriction. More recently, the
Offi ce of Natural Resource and Environmental Policy
and Planning ( ONEP, 2007 ) revised the Thailand Red
Data status for vertebrates, including birds, based on
the IUCN criteria in their 2001 Red List, version 3.1.
The Red Data status for the 13 hornbill species found
in Thailand suggest this group requires urgent conser-
vation actions (Figure 19.1 ): two species, the Black
Anthracoceros malayanus and Wrinkled Rhyticeros
corrugatus Hornbills, are critically endangered; four
species, the Rufous-necked, Plain-pouched Rhyticeros
subrufi collis , Helmeted Rhinoplax vigil and Rhinoceros
Buceros rhinoceros Hornbills, are endangered; six more
species, the White-crowned Hornbill Berenicornis
comatus , White-throated Brown Ptilolaemus austeni ,
Tickell s Brown Hornbills, the Bushy-crested Anorrhi-
nus galeritus , Great and Wreathed Hornbills are vulner-
able; only one species, the Oriental Pied Anthracoceros
albirostris , is of least concern. The evaluation of status
is important, providing warning information and basic
guidelines for setting the priority and degree of inten-
siveness of conservation activities. Since Thailand is
situated on the Asian mainland and extends onto the
Thai-Malay Peninsula, it shares hornbill species with
other geographical areas where the conditions for
effective conservation may differ. Working toward the
conservation of Thai hornbills for their long-term
existence, we need to take serious consideration of our
national status level and that of our neighbors.
Loss of forest means loss of habitat for wildlife, particu-
larly for hornbills, which require large trees for both
nesting holes and for food resources. Due to this, inten-
sive survey and study of threatened and endangered
162 Conservation Biology
Figure 19.1 Sketches of 13 hornbill species and their conservation status.
* National status from Sanguansombat (2005) and ONEP (2007).
Source: Based on Sanguansombat (2005) and ONEP (2007).
Male Female National
status* Male Female National
Endangered Vulnerable
Vulnerable Endangered
Vulnerable Critically
Least concern
White-throated Brown Hornbill
(Anorrhinus austeni)
Rufous-necked Hornbill
(Aceros nipalensis)
Brown Hornbill
(Anorrhinus tickelli)
Bushy-crested Hornbill
(Anorrhinus galeritus)
Oriental Pied Hornbill
(Anthracoceros albirostris)
Black Hornbill
(Anthracoceros malayanus)
White-crowned Hornbill
(Berenicornis comatus)
Great Hornbill
(Buceros bicornis)
Rhinoceros Hornbill
(Buceros rhinoceros)
Helmeted Hornbill
(Rhinoplax vigil)
Wrinkled Hornbill
(Rhyticeros corrugatus)
Plain-pouched Hornbill
(Rhyticeros subruficollis)
Wreathed Hornbill
(Rhyticeros undulatus)
Asia: Conservation of Hornbills in Thailand 163
A consequence of the nest losses is competition for
good cavities, which may subsequently cause nest
abandonment. Competition among animals over a
limited resource is normal and may be enhanced by a
range of factors, such as safe location. In the case of
hornbills at KY, the annual nest abandonment is 36%
of nest cavities (1981–2008), and competition over
nest cavities is as high as 40% ( Poonswad et al ., 2005 ),
with 53% of disputed cavities being abandoned ( Poon-
swad et al ., 1999 ). These two aspects are good clues to
tell us the situation of cavities; we used them when we
began to inspect the condition of the cavities (Table
19.1 ). Of 152 cavities inspected, 123 (80.9%) were
unsuitable and 77 (62.6%) were repaired. The most
serious problems were a sunken nest fl oor (deeper than
15 cm, 50%) and a closed or narrowed entrance (less
than 10 cm wide, 40%). The repair was done prior to
the breeding season, and was a simple operation: soil
lling for cavities with deep fl oor, and enlarging the
entrance by chisel for narrowed or closed entrance.
Realizing the shortage of good cavities, the THP
team has improved those natural cavities that have the
potential to be nests and so increase the breeding
opportunities for hornbills. Over 15 years (1994–
2008), an overall breeding success rate of 86% produced
1137 chicks of four species, of which about 30% suc-
cessfully fl edged from repaired and improved cavities
(Table 19.1 ). Among these, the Great Hornbill, the
largest species, benefi ted most by producing 243
sympatric species, Great, Wreathed, White-throated
Brown and Oriental Pied Hornbills, for breeding at
Khao Yai National Park (KY, 2,168 km
2 ) was begun in
1981 on a 150 km
2 study area within semi-evergreen
forest and continues to the present day.
Implementation of k nowledge
From long-term research at KY, we have amassed a
great sample of nests under observation, and have
proved the success of implementation of eld knowl-
edge to refurbish nesting cavities. Between 1981 and
2008, we located a total of 226 dif ferent nest trees
(Table 19.1 and Figure 19.2 a). Hornbills used mainly
trees of the genera Dipterocarpus of the family Diptero-
carpaceae (40%) followed by Syzygium of the Myrta-
ceae (20%). Nest trees are very large, with a diameter
at breast height (dbh) of, on average, over 100 cm; tall
and emergent above the forest canopy; and hence
mainly aged or over-mature trees. These trees are prone
to damage by wind storms that cause irreversible
breakage to this rare resource. Over 26 years, 42% of
nest trees were lost to strong winds (Table 19.1 ). Nest
cavities that form in these aged trees are also subject to
gradual decay by rot fungi and 50% of those we exam-
ined had become unsuitable for this reason (Table
19.1 ). Losses of nest trees and poor cavity condition
can be a natural threat to breeding hornbills and their
Figure 19.2 Study areas and location of nests at (a) Khao Yai National Park and (b) Budo Mountain.
Permission from the Department of National Parks, Wildlife and Plant Conservation (DNP).
164 Conservation Biology
most desired species could fetch up to US$750 per bird.
Early in 1994, the immediate goal of stopping poach-
ing and increasing hornbill populations was estab-
lished as Phase I. Intensive efforts were undertaken
promptly to convince and persuade villagers to partici-
pate in research and conservation activities, wherein
they became guides and later research assistants.
The project did not develop without some unex-
pected problems. At fi rst, some villagers had reserva-
tions about dealing with non-Muslim strangers, but
these were overcome through person-to-person contact,
ethical project operation and principles, and develop-
ment of mutual respect. In 1997 there was a severe
economic crisis in Thailand, which reduced many local
corporate sources of funds and the resumption of
poaching became a risk. Withdrawal of the project
would have been considered a failure, implying lack of
determination of our part and potentially impairing
the trust we had gained. It was imperative to keep the
project running, despite the economic crisis.
Hornbill f amily a doption
In response to the crisis, fundraising to run the Budo
hornbill conservation program through a program of
“Hornbill Family Adoption” was initiated in 1997. This
successful effort has become recognized as a win-win
program more widely. The program encouraged people
outside BSNP, particularly those living in urban areas,
to participate by making an annual donation for each
hornbill nest that was adopted. All donations went into
training and hiring villagers as guides and assistants,
since overheads for the project were borne inter nally by
the THP. In return, the adopter(s), who chose the
species they preferred, gained knowledge by receiving
an annual report, prepared by THP s staff, with details
of the nest tree, breeding cycle, breeding success, food,
and feeding behavior. They also received pictures of horn-
bills at their nests, hornbill foods, and the villager(s)
who protected and collected data at their nests. Those
who wished to visit the species they had adopted were
welcomed and guided by the villagers, so that the
parties met and conversed. In this way, the practice led
to the initiation of ecotourism related to the project.
On achievement of Phase I, a fur ther goal to increase
and sustain the hornbill populations to reach minimum
viable population size was set as Phase II. An intensive
and continuous community-collaborative campaign of
research and conservation has proven highly success-
ful in eradicating poaching and signifi cantly increasing
chicks, of which 134 (55%) successfully fl edged (Table
19.1 ). Without cavity monitoring and management,
hornbills at KY, particularly Great Hornbills, would
undoubtedly have declined.
Community- b ased c onservation
The s ignifi cance of Budo Mountain
Unlike KY, which is much larger in size and well pro-
tected and managed, Budo Sungai Padi National Park
(BSNP: only 340 km
2 ) was designated as a national
park only in 1999, following 12 years of preparation.
It comprises Budo and Sungai Padi, two isolated moun-
tains situated in peninsular Thailand. These moun-
tains are covered with tropical lowland rainforest,
encompassing the rich biodiversity of fauna and fl ora
of the Thai-Malay Archipelago, a Sundaic habitat that
is of limited extent in Thailand and has been much
reduced in Malaysia. The Park incorporates areas in
three provinces where social unrest has continued
since 2003. In effect, these two mountains are discrete
and separate islands of rainforest within a “sea” of
human-modifi ed habitats that are occupied mainly by
villagers and farmers of Muslim faith.
Amazingly, the forest of Budo mountain (190 km
2 ,
about 90 km
2 of primary forest and 100 km
2 of dis-
turbed forest, rubber plantations, and fruit orchards),
supports six species of hornbills. Some of these species
are of conservation concern internationally, including
the Rhinoceros, Helmeted, and White-crowned Horn-
bills. They are also of high concern nationally, particu-
larly the Rhinoceros Hornbill that was previously
thought to have become extinct in Thailand. During
the period 1994–2008, 188 nest trees of these six
hornbill species were located by ex-poachers and
ex-illegal loggers (villagers hereafter) (Table 19.1 ,
Figure 19.2 ). Budo has been under military operations
for most of the years during our research and conser-
vation practices.
Initiation of c ommunity- b ased c onservation
Before 1994, hornbills at Budo were severely poached
for the pet trade and food, and were in jeopardy of
extinction. The discovery of poaching of hornbill
chicks from their nests and their illegal sale into avicul-
ture and the pet trade was an important source of sup-
plementary income in the villagers lives, given that the
Asia: Conservation of Hornbills in Thailand 165
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of nutrients delivered to nest inmates by four sympatric
species of hornbills in Khao Yai National Park, Thailand .
Ornithological Science , 3 , 99 – 112 .
Poonswad , P. , Chimchome , V. , Plongmai , K. and Chuailua , P.
( 1999 ) Factors infl uencing the reproduction of Asian
hornbill populations, particularly those of two of the
endangered species (Table 19.1 ). Over 16 years, under
this community-based conservation, there were no less
than 440 hornbill chicks of six species fl edged, 50%
being Great and 26% Rhinoceros Hornbills (Table
19.1 ).
Despite the poor economic conditions, exacerbated
by regional unrest, which has a pervasive effect on
community lives and livelihoods around Budo, the
hornbills remain under this form of community care.
Around Budo, the annual outreach campaign among
school children and teachers about hornbills and
nature conservation shows a progressive increase in
numbers from 200 individuals in 2006 to 1600 in
2010. Even though a nest cavity is an important factor
for hornbills to reproduce, at Budo the future of horn-
bills relies on community concern as the prime factor.
With limiting natural resources in a conservation
context, it is a challenge to transform an economically
based community into an altruistic community. If a
community does realize the intrinsic value of their
natural heritage with pride, as a gift to future genera-
tions, as a responsibility, rather than focusing on eco-
nomic benefi t, then conservation in these forests will
truly bloom. Partnerships with outsiders who may help
to support the effort fi nancially can also be extremely
We are deeply indebted to the late Professor Sodhi, who
inspired and kindly included a part of our research in
this valuable book. We would like to thank the Depart-
ment of National Parks, Wildlife and Plant Conserva-
tion for granting permission to conduct research in
Khao Yai and Budo Sungai Padi National Parks. We
extend our thanks to park superintendents, park staff,
THP staff, and villagers of Budo Mountain for data col-
lection and excellent cooperation. We are grateful to Dr
Alan Kemp for his unlimited assistance. Our special
thanks go to Preeda Thiensongrusme for illustrations
of hornbills and to Porntip Poolswat for preparation of
this manuscript. Research and conservation activities
are supported by various organizations and private
sectors: Thailand, National Center of Genetic Engi-
neering and Biotechnology, Hornbill Research Founda-
tion, the Siam Cement Group, I.C.C International
Public Company Limited, PTT Exploration and Produc-
tion Public Company Limited, Mahidol and Kasetsart
166 Conservation Biology
Santisuk , T. ( 2007 ) Forests of Thailand . Department of National
Parks, Wildlife and Plants Conservation , Bangkok, Thailand .
Trisurat , Y. ( 2007 ) Applying gap analysis and comparison
index to evaluate protected areas in Thailand . Environmen-
tal Management , 39 ( 2 ), 235 – 245 .
Trisurat , Y. , Pattanavibool , A. , Gale , G. A. and Reed , D. H.
( 2010 ) Improving the viability of large mammal popula-
tions using landscape indices for conservation planning .
Wildlife Research , 36 , 401 – 412 .
hornbills , in Proceedings of 22nd International Ornithological
Congress, Durban (eds N. J. Adams and R. H. Slotow ), 1740 –
1755 . BirdLife South Africa , Johannesburg, South Africa .
Poonswad , P. , Sukkasem , C. , Phataramata , S. , Hayeemuida ,
S. , Plongmai , K. , Chuailua , P. , Thiensongrusame , P. and
Jirawatkavi , N. ( 2005 ) Comparison of cavity modifi cation
and community involvement as strategies for hornbill
conservation in Thailand . Biological Conservation , 122 ,
385 – 393 .
RFD (Royal Forest Department) ( 1985 ) National Forest Policy .
Royal Forest Department , Bangkok, Thailand .
Sanguansombat , W. ( 2005 ) Thailand Red Data: Birds . Offi ce of
Natural Resources and Environmental Policy and Planning
(ONEP) , Bangkok, Thailand .
... These birds live in monogamous pairs (i.e., with one male and one female) and occupied about 1.2km2 to 2.3km2 of forest area per pair (Bennett,Adrian & Sompud, 1997). They generally require intact primary forest that provides suitable nest sites (natural cavities) and sufficient food resources (Poonswad et al, 2013). These species of hornbills play significance role in the indigenous people across the world, including in Borneo (Bennett,Nyaoi & Sompud, 1997;Collar, 2015;Poonswad, Chimchome, Mahannop & Mudsri, 2013). ...
... According to the findings of a long-term research carried out byPoonswad et al. (2013)in Bodo Mountain (bordering Peninsula Malaysia), Thailand, hornbills rely entirely on the availability of natural tree cavities for reproduction and depend very much on fruit as their food resource, any loss of habitat means loss not only of breeding sites but also of food resources, and because of their rigid requirement for breeding sites, these hornbills are inevitably threaten by any human activities within forests, besides such natural phenomena as storm and decomposition process that are also considered important threats to hornbill populations.Poonswad et al.pointed out that a shrinkage of forest areas or deforestation poses the most serious threat to hornbills and followed by hunting activities, including hunting of hornbills. In addition, the authours defined that the " loss of forest means loss of habitat for wildlife, particularly for hornbills, which require large trees for both nesting holes and for food resources " …. " Losses of primary forests have impacts on hornbill populations by reducing their potential breeding sites and depleting their food resources ". ...
... The most obvious consequence of forest destruction is the loss of dominant large trees, particularly trees in the genera Dipterocarpus, Hopea and Shorea (Dipterocarpaceae). The result of a research of over 26 years byPoonswad et al. (2013)indicates that hornbills used mainly trees of the genera Dipterocarpus of the family Dipterocarpaceae (40%) followed by Syzygium of the Myrtaceae (20%) as nest trees. Nest trees are very large, with a diameter at breast height (dbh) of, on average, over 100 cm; tall and emergent above the forest canopy; and hence mainly aged or over-mature trees (Table 1).Table 1: Common nest-trees used by hornbills (Poonswad et al., 2013In the state of Sarawak, prior to the Brooke Era, the Iban people during their massive migration expansion through Sarawak have evidently pioneered the clearing of massive forest areas and occupied the land which are presently recognised by the government of the day as Native Customary Right land (NCR). ...
Conference Paper
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In the island of Borneo, the forests ecosystem, rivers and wildlife prior to the pre-Brookes era have notably influenced the evolution of their indigenous knowledge, practices and beliefs system, which over time has developed into acceptable cultural and traditional identity of indigenous people which is increasingly being sought after by academicians, researchers and policy makers as potential source of ideas for emerging models of ecosystem management, conservation biology and ecological restoration. Today, changes in the political and socioeconomic development, driven by the flattening, crowding and warming of the world have devoured open space and tropical rainforest which in turn to some extent disrupt ecosystems and deplete species that has been perceived increasingly impacting the dynamic nature of the beliefs and cultural system of many indigenous communities. This paper elicits some factors and conditions that maintain or undermine indigenous communities' ability to adapt, generate, transmit and apply the traditional knowledge, beliefs and cultural systems with respect to the species of hornbills and its conservation in the face of changing environmental and socioeconomic conditions.
... Today, their natural habitat remains largely fragmented and with an extraordinarily high level of threats to their persistence [14]. e target species rufous-necked hornbill has been reported to be extinct in Nepal and close to extinction in Vietnam [15,16]. To date, no study has been carried out to know regarding hornbill's habitat suitability and distribution in Bhutan. ...
... According to the current study, the probability of GH occurrence is high below 3000 masl. e great hornbill is known to frequent wet evergreen and mixed deciduous forests, ranging out into open deciduous areas to visit fruits and ascend slopes to at least 1,560 masl in south India [32] and up to 2,000 masl in ailand [15]. e RNH is found in primary subtropical evergreen and deciduous forests between 600 and 2000 masl worldwide but have been seen as high as 2900 masl [33]. ...
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The great hornbill (Buceros bicornis) and rufous-necked hornbill (Aceros nepalensis) are listed as vulnerable under the International Union for Conservation of Nature Red List of threatened species due to the rapid decline of their population in the world. This research focuses on analyzing the habitat suitability of these two important bird species across Bhutan. A total of 51 presence locations were recorded from the field survey. The models were simulated using three topographic variables and 19 bioclimatic variables. The MaxEnt modelling technique was used for delineating the distribution potential habitat suitability map. The habitat suitability analysis for great hornbill and rufous-necked hornbill shows that 2% and 3% of Bhutan’s total geographical area were highly suitable, respectively. The approach of this study will be beneficial in identifying suitable areas and aid decision-makers in management and conservation of these vulnerable bird species.
... In addition to distribution and abundance of food resources, other potential limiting factors for sustaining healthy hornbill populations include the presence of natural tree cavities suitable for breeding and adequate roosting sites (Poonswad 1993, Poonswad 1995, Poonswad et al. 1999, Datta & Rawat 2004, Poonswad et al. 2013a. Being secondary cavity-nesters, Asian hornbills do not create tree cavities on their own (Chuailua et al. 1998, Datta & Rawat 2004, Poonswad et al. 2013b, Pasuwan et al. 2015. ...
... In Thailand, the two main tree genera and families of hornbill nest trees were Dipterocarpus (Dipterocarpaceae) and Syzygium (Myrtaceae) (Poonswad et al. 2013a). In Kinabatangan, in addition to Dipterocarpaceae, tree families such as Rubiaceae, Moraceae, Malvaceae, Anacardiaceae, Acanthaceae and Erythroxylaceae have been reported as preferred nesting trees of hornbills (Kaur et al. 2018, Kaur 2020. ...
Eight species of hornbill occur in the Lower Kinabatangan Wildlife Sanctuary, Sabah. Hornbills are secondary cavity-nesting birds and one of the limiting factors to sustain their numbers is the availability of naturally-formed tree cavities. Past timber extraction has left behind highly degraded forest patches without large emergent trees that usually provide suitable cavities for nesting hornbill pairs. Therefore, we conducted a study to assess how widespread this key resource is and to estimate the proportion of a forest patch currently occupied by potential nest trees, i.e. trees with cavities. In a 10 km2 study site, eight trained observers systematically visited 30 250 m x 250 m plots and recorded tree cavities that appeared suitable for hornbills based on a pre-established list of criteria. Nineteen trees with cavities were located, measured and identified. We anticipated that cavities could go undetected by the observers; we therefore used a zero-inflated process occupancy model to address this measurement error and to analyse data obtained along transects. The observers detected trees with cavities in 10 out of 30 plots, translating into an observed proportion of roughly 33%. However, our model indicated that trees with cavities might actually occupy 25 out of 30 plots, i.e. 82% of the forest patch area. Our modelling approach incorporates imperfect detection through hierarchical modelling and constitutes a quick and cost-effective assessment tool that can be used to investigate the spatial presence of potential nest trees, an important resource for hornbills.
... Being secondary cavity nesters, hornbills depend on cavities formed in large trees for nesting (Kemp 2001); the reduced availability of suitable nest trees due to habitat modification may influence population dynamics (Cody 1985;Lindenmayer & Laurance 2017). As predominantly frugivorous birds (Kemp 2001;Kinnaird & O'Brien 2007;Poonswad et al. 2013) that track patchily distributed fruit resources in space and time (Kinnaird et al. 1996;Whitney & Smith 1998;Anggraini et al. 2000;Naniwadekar et al. 2015a), hornbills may also be affected when the diversity and abundance of fruiting trees and fruit availability declines in disturbed and modified habitats (Whitney & Smith 1998;Tabarelli et al. 1999;Sitompul et al. 2004;Lenz et al. 2011). Sumatran hornbills have been reported to avoid highly disturbed areas (Anggraini et al. 2000), while the size of forest patches and the abundance of food plants is known to influence hornbill occurrence and abundance in forest fragments in India (Raman & Mudappa 2003;Naniwadekar et al. 2015b). ...
... Hornbills are known to occasionally abandon nests even in primary forests. The relatively high nesting success in this study was similar to that reported for the Great Hornbill across its range (Mudappa & Kannan 1997;Datta & Rawat 2004;Poonswad et al. 2013;Rane & Datta 2015). Earlier studies have reported hornbills using degraded, fragmented, and modified habitats (Johns 1987;Datta 1998;Marsden & Pilgrim 2003;Mudappa and Raman 2009;Naniwadekar et al. 2015b), even for breeding (Rane & Datta 2015). ...
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Abstract Loss of mature tropical forests to agricultural expansion often creates landscapes with forest fragments embedded within a matrix of human-modified habitats and land uses. Such habitat fragmentation may be detrimental to species with specialized habitat and foraging requirements and their ability to persist in such landscapes may depend on their adaptability to habitat modification. Great Hornbills Buceros bicornis, among the largest birds in Asian tropical rainforests, depend on large trees for nesting and a diverse array of patchily distributed fruiting trees. In the human-modified landscape of the Anamalai Hills, India, we compared the breeding biology and nesting behaviour of Great Hornbills in contiguous rainforest (N=3 nests) and in modified habitat consisting of coffee plantations and rainforest fragments (N=5 nests). The nesting cycle of seven of the eight nests monitored varied between 114 and 130 days. Nest provisioning behaviour was similar in contiguous forest and modified habitat in terms of visitation and food delivery rates, but visitation tended to be higher and food delivery rate lower during the nestling phase than during incubation. As expected, tree density and native food plant diversity were lower in modified habitat than in continuous forest. The diversity of food provisioned was lower in modified habitat with a 57.5% dietary overlap with contiguous forest. Hornbills in the modified habitat of coffee plantations used non-native tree species for nesting and foraging, indicating their adaptability to modified landscapes. Key words Breeding biology, forest fragmentation, Great Hornbill, habitat alteration, nesting behaviour
... This conflict threatens hornbills as it limits the availability of suitable nest cavities (Poonswad et al., 2005), which restrict the potential reproduction rate (Chantarat et al., 2011), as well as food sources and security of a population. Poonswad et al. (2013) reported that the eradication of the Wreathed, Great, and Rufous-necked Hornbills in Northern Thailand was largely due to deforestation, which creates fragmentation. Pattanavibool and Dearden (2002) found that the Tickell's brown and great hornbills survived only in large forest patches and when found in smaller patches, only occurred in small numbers. ...
... Two subspecies, G. g. gallus and G. g. spadiceus, distributed across Thailand 25,26 , are distinguished only by their external characteristics, and no population genetics study on the genetic diversity between the two subspecies has been carried out. In Thailand, red junglefowl is strictly protected under the National Park Act since 1961 and the revised Wild Animals Reservation and Protection Act since 1992 27 . Thai indigenous chickens are generally reared under free range backyard conditions by small-scale poultry farmers, and a variety of breeds have been established from indigenous populations and maintained as closed colonies ever since. ...
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In this study, we aimed to elucidate the origin of domestic chickens and their evolutionary history over the course of their domestication. We conducted a large-scale genetic study using mitochondrial DNA D-loop sequences and 28 microsatellite DNA markers to investigate the diversity of 298 wild progenitor red junglefowl (Gallus gallus) across two subspecies (G. g. gallus and G. g. spadiceus) from 12 populations and 138 chickens from 10 chicken breeds indigenous to Thailand. Twenty-nine D-loop sequence haplotypes were newly identified: 14 and 17 for Thai indigenous chickens and red junglefowl, respectively. Bayesian clustering analysis with microsatellite markers also revealed high genetic diversity in the red junglefowl populations. These results suggest that the ancestral populations of Thai indigenous chickens were large, and that a part of the red junglefowl population gene pool was not involved in the domestication process. In addition, some haplogroups that are distributed in other countries of Southeast Asia were not observed in either the red junglefowls or the indigenous chickens examined in the present study, suggesting that chicken domestication occurred independently across multiple regions in Southeast Asia.
... Involvement of local community has been successful in removing threat to poaching of Hornbills and also ensures continued co-existence of humans and Hornbills (Poonswad et al., 2005;Poonswad et al., 2013;Naniwadekar et al., 2014). ...
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Manipur is a part of a global biodiversity hotspot and two endemic bird areas. In this study at Kailam Wildlife Sanctuary (187.50 sq. km), a survey was carried out for five Hornbill species that occur here: Oriental Pied Hornbill Anthracoceros albirostris, Austen’s Brown Hornbill Anorrhinus austeni, Wreathed Hornbill Rhyticeros undulates, Rufous-necked Hornbill Aceros nipalensis and Great Hornbill Buceros bicornis. Only three hornbill species were sighted during the study period: Oriental Pied Hornbill (n=10), Brown Hornbill (n=15-21) and Wreathed Hornbill (n=2). However, the questionnaire survey conducted suggests that all five Hornbill species are present in the area. Oriental Pied Hornbill is widely distributed in the area while Brown Hornbill is found in dense forest patches. Wreathed Hornbill is rare as they are seasonal visitors. Rufous-necked Hornbill and Great Hornbill are rarely seen. A checklist of birds was also prepared where a total of 145 bird species from 34 families were recorded. During the three month survey of status and distribution of Hornbills, Wreathed Hornbill was sighted only once, Brown hornbill was sighted four times and Oriental Pied Hornbill seven times. Most sightings were in primary forests and riverine forests except one sighting in secondary forest. Types of disturbances recorded for the area of sighting are hunting, logging, vehicular road, trapping and forest fire. Hunting is the most common disturbance found at every site, followed by trapping, logging, vehicular road, and forest fire. All hornbill species were observed within the altitudinal range of 450-1500 m. Oriental Pied Hornbills were observed between 450- 750 m, Brown Hornbills between 750-1000 m and Wreathed Hornbill between 1400-1500 m. In this study, peoples’ awareness about the protected area, perception and attitude towards conservation were examined through questionnaire survey. A total of 129 respondents from six villages were sampled. The mean family size of respondents (82.95% Male, 17.05% Female) is 6 where 90% of the respondents were literate of which 81% had studied at least till the primary level. There is no significant difference between gender and education (χ2 (3) = 3.855, p > 0.05). The primary occupation of the respondents is shifting cultivation and their average annual income is around 40,900 INR where 10.01% comes from livestock and another 10.74% from resources collected from the forest, the majority of which is from fish and timber. Gender, family and landholding does not have any significant relationship with annual income (p > 0.05) however educational qualification shows significant effect on annual income; χ2 (6) = 12.692, p < 0.05. Firewood/Fuelwood is the most common source of energy and is used by every household. Of the 129 respondents 82.95% (n=107) were aware that the area is a proposed Wildlife Sanctuary while the rest 17.05 (n=22) were not aware about it. Males and females differed in their awareness about the proposed wildlife sanctuary (p < 0.005). More males (86%) were aware about the creation of a protected area compared to females (55%). A significant difference was also found in the number of Hornbill species seen by male and female respondents (p < 0.001). Only 1% of male respondents have never seen any hornbill species compared to 18% for females (residual value = 3.4). The majority of respondents think that the creation of KWLS would deprive them of their livelihood (n=107) and would not create opportunities (n=77). 60% (n=77) of the respondent thinks that wildlife needs to be protected. Meanwhile 87% (n=112) are interested in tourism and 59% (n=76) of the total respondent thinks they will benefit from tourism. To improve relations between forest department and local people, a majority of the respondents feel that they should involve local people in decision making and management plans (42%), followed by employment (18% ) - employment as official (9%) and secondary employment (9%) – awareness campaigns (13%), others (15%) such as alternative livelihood, schemes, etc. and the rest (12%) do not know. The result from the survey suggests that hunting (41%), habitat loss (22%) and no awareness (19%) among the local people are the major factors that undermine conservation and the rest 10% of the respondents think that low income and poor livelihood opportunities also undermine conservation efforts. Hunting by local communities is a direct threat to the survival of Hornbills while logging in primary forest is a major threat to their habitat and construction of road in logged areas provides easy accessibility for hunting. Therefore, the need of the hour is to promote research based and community based approach towards conservation. This study is an attempt at creating awareness through research-based approach.
... There are also studies reporting abundance of hornbill species in logged forests [14,66]. The emerging consensus is that logging would lead to reduction in hornbill species if there is a reduction in fruit-bearing and nest-worthy trees [82,83]. The positive correlation between abundance of fruits and hornbill population is well understood [8,10], and it is possible that loss of fruiting trees in the neighbouring Malaysian Borneo due to logging and industrial plantations have led to the migration of hornbills to Temburong. ...
Full-text available
Background: Hornbills are known to play an important role in rainforests as agents of seed dispersal. Decades of scientific research has led to a vital body of knowledge on hornbill taxonomy, ecology, distribution, and conservation status. However, the traditional ecological knowledge (TEK) that local people possess on hornbills has largely been underexplored. In 2018, we collaborated with the Iban people of Temburong, Brunei Darussalam, to study their TEK on hornbills. Method: We collaborated with the members of the Iban community from four longhouses and four villages in Temburong, Brunei Darussalam. Our study adopts a qualitative approach; we used detailed semi-directive interviews and brief semi-structured interviews to gather data. The semi-directive interviews documented the TEK related to Hornbills in detail while the brief semi-structured interviews assessed the current status of TEK in the age group of 18-40 years. Results: The results show that the Iban ethnotaxonomy recognises seven folk species of hornbills, with Asian Black Hornbill (Anthracoceros malayanus) and Oriental Pied Hornbill (Anthracoceros albirostris) considered as a single folk species. The Iban TEK on diet and reproductive behaviour of hornbills complement existing scientific records, with the Iban TEK providing additional locale-specific information on the dietary preferences, abundance and conservation threats. However, the average Iban member has lost much of this TEK, and it is the subsistence hunters and agriculturists who have conserved it. Conclusion: There is an urgent need for encouraging transmission of knowledge from the hunters and agriculturists to others through ecotourism and conservation ventures. Our study adds further support to the understanding that the TEK of local communities is an important source of locale-specific knowledge on species of high conservation value such as hornbills.
Nest boxes are a conservation tool for increasing the availability of nests. The efficacy of nest boxes can be assessed by examining the breeding parameters of birds in nest boxes to see whether data are comparable with tree cavities. The hornbill artificial nest research was conducted in Budo-Su-Ngai Padi National Park, Thailand since 2003. This project aims to increase the breeding propensity of two large species of hornbills; the Great Hornbill (Buceros bicornis) and the Rhinoceros Hornbill (Buceros rhinoceros) that coexist in the study area, by utilizing nest boxes. The nest boxes were constructed from fiber-reinforced plastic. There were two designs; small nest box: 50 x 49 cm at base and 95 cm height, and large: 65 x 70 cm at base and 95 cm height. Twenty nest boxes were installed between 2004 and 2006. These nest boxes were monitored from 2004 to 2021. The study results indicated that the proportion of nest occupancy of Great Hornbill breeding in natural nests was higher than nest boxes: 48.9% and 31.4%, respectively (the two binomial proportions test gives: Zc= 4.01, P < 0.0006 < α = 0.05). The results also showed that the Great Hornbill prefers to select a large nest box than a small one: 37.3% and 17.3%, respectively (the two binomial proportions test gives: Zc = 3.4, P < 0.00068 < α = 0.05). Eight nest boxes so far have been utilized by hornbills: six by Great Hornbill with 58 nesting successes and two by Rhinoceros Hornbill with 1 nesting success. The average life cycle of the fiberglass nest box is about 11.38±4.23 SD years. The study results suggest that reproduction parameters of hornbills in nest boxes are different from natural cavities in many aspects. Our two target species do not equally benefit from nest boxes.
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Conservation education programs are listed as priority actions for almost every threatened species on the International Union for Conservation of Nature Red List. Zoos play an important role in delivering such programs, yet evidence of zoo education in many non-western countries is limited. Here, we evaluate animal identification signage prevalence and quality at zoo exhibits and investigate whether animal welfare, zoo type (accredited, government, and private), admission fee, zoo size, and proximity to urban centers are influencing factors. We used hornbills (Bucerotidae) as a model taxon, surveyed hornbill signage, and conducted welfare assessments of hornbill exhibits. We developed scoring frameworks and applied content analysis to analyze signage quality. Our results show that out of 18 zoos that displayed hornbills, 15 had hornbill signage. However, of the 106 hornbill exhibits in these zoos, 33% had no signage. We also found that signage presence or absence at individual zoos and signage quality is strongly correlated with animal welfare quality. Zoo type is a key factor in predicting signage and welfare quality, with accredited zoos scoring highest for both signage and welfare, followed by government and private zoos. Private zoos charged higher admission than other zoo types, and zoo size and proximity to urban centers did not influence signage or welfare scores. Overall, we conclude that in our study, signage usage and quality are inadequate, highlighting the importance of compliance with robust zoo standards to improve education and welfare within zoos to support global conservation goals.
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Hornbills are omnivorous and the breeding male delivers all food required by the nest-confined female and chicks. The contributions of different food types, in terms of breeding nutrition, have not previously been documented. In Khao Yai National Park, Thailand, we sampled the identity and number of food items delivered daily to the nest, during each week of the nesting cycle, by two small and two large sympatric species of hornbills. We then recorded the mass and estimated the nutrient content of each food type from analyses of protein, fat, carbohydrate, calcium, and energy. The overall pattern of nutrient delivery during the nesting cycle was the same for each of the four hornbill species, and was related to sequential demands for egg, feather, and chick development. The two larger species delivered mainly carbohydrates (Great Buceros bicornis 50%, Wreathed Aceros undulatus 57%) and less fat and protein. The smallest, Oriental Pied Hornbill Anthracoceros albirostris, also delivered mostly carbohydrate (45%), but the small White-throated Brown Hornbill Anorrhinus austeni delivered equivalent proportions of protein (32%), fat (30%), and carbohydrate (37%). Comparison of the incubation and nestling phases showed that more protein was delivered during the nestling phase for all species, except for Great Hornbill where the compression of egg production, incubation, and molt had to be completed by midway through the nestling phase and so high levels of fat and protein were delivered during incubation. We confirmed that fruits are an important source of all nutrients, especially fat, for all four hornbill species, but suggest that delivery of animal protein may be linked, in some way, to breeding success. Oriental Pied Hornbill broods, that received protein at about 1.05% of brood mass per day, had the highest breeding success (96%) whereas Wreathed Hornbills received only 0.57% protein and had only 67% success, while the other two species delivered intermediate amounts of protein and had intermediate breeding success.
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Ranges of individual males of three hornbill species were determined by radio telemetry during the breeding and non-breeding seasons in Khao Yai National Park, Thailand. Two Great Hornbills Buceros bicornis and two Brown Hornbills Ptilolaemus tickelli were studied in both 1988 and 1989, and two Wreathed Hornbills Rhyticeros undulatus were studied in 1989, 1990 and 1991. In the breeding season, the home range of the Great Hornbill was 3.7 km2, similar to that of the Brown Hornbill (4.3 km2), while the Wreathed Hornbill occupied the largest home range (10.0 km2). In the non-breeding season, the range size of the Wreathed Hornbill (28.0 km2) was greater than that of the Great Hornbill (14.7 km2). Differences in range sizes of different species may be related to differences in diet and breeding strategy. Ranges overlapped within and between the species, and this has implications for the estimation of the minimum area required for the conservation of hornbills within the Khao Yai National Park.
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Characteristics of nest sites, nest trees and nest holes were documented for four sympatric species of hornbills in Khao Yai National Park: the Great Buceros bicornis. Wreathed Rhy-ticeros undulatus, Oriental Pied Anthracoceros albirostris and Brown Hornbills Ptilolaemus tickelli. Nearly all hornbills nested in cavities in the trunks of at least 13 different genera of living trees. Sixty percent of the 80 nests found were in two tree genera, Dipterocarpus (34%) and Eugenia (26%), which comprised only 7% and 3%, respectively, of all large trees in 302 sample plots. Hornbills tended to prefer holes high in large, emergent trees for nesting, except for the Brown Hornbills, which preferred nest holes within or below the main forest canopy (15–25 m high). Most nest sites were between 700 and 800 m a.s.l. (79% of the total of 80 nests). Brown Hornbill nests were located in areas with a significantly higher altitude than were those of the Oriental Pied Hornbill. Hornbills tended to select nest entrances according to their body size, and all four hornbill species used oval to elongated nest entrances, with the Great Hornbill preferring the most elongated entrances. Hornbills did not select a specific nest entrance orientation.
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We monitored breeding success of hornbills in Thailand for four sympatric species at Khao Yai National Park during 1981–2002 and six species at Budo-Sungai Padi National Park during 1994–2002. Within a 60 km2 study area at Khao Yai, the well protected area, use of available cavities ranged from 94% in 1984 to 50% in 1993. Competition for nesting cavities was 40% of cavities available indicating the shortage of suitable cavity. We monitored the cavity condition and modified 48 cavities and, between 1996 and 2000, these contributed annually 23–45% of nestings that were successfully fledged (n = 352). Within the 90 km2 at Budo Mountain, with heavy human disturbance, use of available cavities for nesting decreased from 81% in 1997 to 30% by 2001 and of successful fledging from 96% in 1997 to 55% in 1999, but both increased once our involvement with local communities had eradicated poaching and reduced disturbance. Competition for nesting cavities here was 26% of cavities available indicating the effect of poaching. Both strategies were successful in the short term but long-term management of cavities in large forest trees is required at Khao Yai and of forest disturbance at Budo.
[Now replaced by the 3rd Edition, 2019]] This book is a thorough update of the first textbook dedicated to the terrestrial ecology of the East Asian tropics and subtropics, from southern China to western Indonesia, originally published in 2009. The geographical coverage of the new edition has been enlarged to include the very similar ecosystems of northeast India and Bhutan. Tropical East Asia is home to over one billion people and faces massive human impacts from its rising population and rapid economic growth. It has already lost more than two-thirds of its forest cover and has the highest rates of deforestation and logging in the tropics. Hunting, coupled with the trade in wildlife products, threatens all its large and many of its smaller vertebrates. Despite these problems, the region still supports an estimated 15-25% of global terrestrial biodiversity and is therefore a key area for conservation. Effective conservation action depends on a clear understanding of the ecological patterns and processes in the region. The book deals with plants, animals, and the ecosystems they inhabit, as well as the diverse threats to their survival and the options for conservation. It provides the background knowledge of the region's ecology needed by both specialists and non-specialists to put their own work into a broader context. The accessible style, comprehensive coverage, and engaging illustrations make this advanced textbook an essential read for senior undergraduate and graduate level students studying the terrestrial ecology of the East Asian tropics, as well as an authoritative reference for professional ecologists, conservationists, and interested amateurs worldwide. CONTENTS: 1: Environmental history 2: Physical geography 3: Biogeography 4: The ecology of plants: from seed to seed 5: The ecology of animals: foods and feeding 6: Energy and nutrients 7: Threats to biodiversity 8: Conservation: saving all the pieces
Context. Assessing the viability of animal populations in the wild is difficult or impossible, primarily because of limited data. However, there is an urgent need to develop methods for estimating population sizes and improving the viability of target species. Aims. To define suitable habitat for sambar (Cervus unicolor), banteng (Bos javanicus), gaur (Bos gaurus), Asian elephant (Elephas maximus) and tiger (Panthera tigris) in the Western Forest Complex, Thailand, and to assess their current status as well as estimate how the landscape needs to be managed to maintain viable populations. Methods. The present paper demonstrates a method for combining a rapid ecological assessment, landscape indices, GIS-based wildlife-habitat models, and knowledge of minimum viable population sizes to guide landscape-management decisions and improve conservation outcomes through habitat restoration. Key results. The current viabilities for gaur and elephant are fair, whereas they are poor for tiger and banteng. However, landscape quality outside the current distributions was relatively intact for all species, ranging from moderate to high levels of connectivity. In addition, the population viability for sambar is very good under the current and desired conditions. Conclusions. If managers in this complex wish to upgrade the viabilities of gaur, elephant, tiger and banteng within the next 10 years, park rangers and stakeholders should aim to increase the amount of usable habitat by similar to 2170 km(2) or 17% of existing suitable habitats. The key strategies are to reduce human pressures, enhance ungulate habitats and increase connectivity of suitable habitats outside the current distributions. Implications. The present paper provides a particularly useful method for managers and forest-policy planners for assessing and managing habitat suitability for target wildlife and their population viability in protected-area networks where knowledge of the demographic attributes (e.g. birth and death rates) of wildlife populations are too limited to perform population viability analysis.
Long-distance seed dispersal influences many critical ecological processes by improving chances of gene flow and maintaining genetic diversity among plant populations. Accordingly, large-scale movements by frugivores may have important conservation implications as they provide an opportunity for long-distance seed dispersal. We studied movement patterns, resource tracking, and potential long-distance seed dispersal by two species of Ceratogymna hornbills, the black-casqued hornbill C. atrata, and the white-thighed hornbill C. cylindricus, in lowland tropical forests of Cameroon. We determined fruiting phenology of 24 tree species important in hornbill diet at monthly intervals and compared these patterns to monthly hornbill census data. After capture and radio-tagging of 16 hornbills, we used radio telemetry by vehicle and fixed wing aircraft to determine the extent of long-distance movements. Hornbills exhibited up to 20-fold changes in numbers in response to fruit availability in our 25 km(2) study area. Also, hornbills made large-scale movements up to 290 km, which are larger than any movement previously reported for large avian frugivores. Together, these observations provide direct evidence that hornbills are not resident and that hornbills track available fruit resources. Our results suggest that Ceratogymna hornbills embark on long-distance movements, potentially dispersing seeds and contributing to rain forest regeneration and diversity.
Protected areas in Thailand were first established 40 years ago. The total area of existing protected areas covers 18.2% of the country's land area and the Class 1 Watershed, another form of protection, encompasses 18.1%. The government of Thailand intends to increase protected area systems to 25% of the country in 2006 and 30% in 2016. There are always questions arising about how much is enough protected areas to effectively protect biodiversity. The objective of this article is to assess the representation of ecosystems in the protected area network. This article also recommends which underrepresented ecosystems should be added to fill the gaps in representativeness. The research applies a gap analysis and a comparison index to assess the representation of ecosystems within the protected area network. The spatial analyses were applied to measure three aspects of representativeness, namely forest type, altitude, and natural land system. The analyses indicate that the existing protected area system covers 24.4% of the country's land area, nearly meeting the 25% target proposed by the National Forest Policy; and 83.8% of these areas are under forest cover. Most protected areas are situated in high altitudes, where biological diversity is less than in lowlands. Mangrove forest and riparian floodplain are extremely underrepresented in the existing system. Peat swamp forest, dry dipterocarp forest, and beach forest are relatively well represented. In addition, these five ecosystems are threatened by human pressures and natural disasters; therefore, they should be targeted as high priorities for the selection of new reserves. Future research should incorporate aquatic and marine ecosystems, as well as animal distributions, which were not included in this research due to data unavailabilities.