Hornbill Species Research Articles

Hornbill abundance and breeding incidence in relation to habitat modification and fig fruit availability

Asian hornbills are known to forage and breed in fragmented rainforests and agroforestry plantations in human‐modified landscapes adjoining contiguous protected forests. However, the factors influencing year‐round hornbill abundance, demography and tracking of key food resources such as wild fig Ficus fruits in modified habitats and protected forests remain poorly understood. We carried out monthly surveys of two species of high conservation concern, the Vulnerable Great Hornbill (GH, Buceros bicornis) and the endemic Malabar Grey Hornbill (MGH, Ocyceros griseus) for 15 months and monitored ripe fig fruit availability for 12 months along 11 line transects (total length 24 km) in shade‐coffee plantations and adjoining continuous rainforests in a protected area (PA) in the Anamalai Hills, Western Ghats, India. Both hornbill species used plantations and the PA year‐round but distance sampling density estimates were higher in the PA in both nesting (GH by 57%; MGH by 50%) and non‐nesting (GH by 53%; MGH by 144%) seasons. Relative to estimates from 2004 to 2005, mean GH density appeared stable or increasing, whereas MGH had declined by 39% in the PA and by 56% in plantations. Monthly encounter rate of both hornbills tended to be higher in the PA and that of MGH was also positively related to the density of fig trees with ripe fruit. Sex ratios of observed adult birds in the non‐nesting season were relatively even (GH) or slightly female‐biased (MGH), but became male‐biased in both species during the nesting season when females were confined in tree‐cavity nests. We used change in the adult sex ratio of observed birds from the non‐nesting to nesting season to estimate an index of the proportion of adult pairs breeding at any point within the season, providing the first such estimates for any hornbill species. The proportion of breeding pairs was higher in the PA (GH – 56%, MGH – 64%) than in the plantations (GH – 33%, MGH – 30%). Although hornbills use shade‐coffee plantations year‐round, partly due to fig fruit availability, differences in hornbill density and breeding incidence, as assessed from the sex ratios of observed adult birds, indicate that plantations are a sub‐optimal habitat for both species.

A brief report on the development of dorsal air sacs in hand reared Von der Decken’s hornbills (Tockus deckeni)

Several species of hornbills are known to develop dorsal air sacs after hatching, which present as a pocket of air under their skin. These increase in size as the chicks grow, and gradually disappear as the chicks develop feathers. However, this feature is not well-described, nor do we know the extent it occurs in Bucerotids. Here, it is reported in a clutch of hand-reared Von der Decken’s hornbills ( Tockus deckeni) ( n = 5) at Jurong Bird Park, Singapore. Air sacs were not present at hatch, but developed within 24 h, increasing in size until about 10 days of age. They gradually recede from this age and are not always inflated, disappearing at about 16 days of age when the chick has considerable feather growth. The functions of this unique feature are largely unclear, but it is thought to be mostly related to thermoregulation. Further research is required to determine this, possibly using captive specimens from zoological institutions as it is more difficult to collect data from wild birds.

Persistent loss of biologically-rich tropical forests in the Indian Eastern Himalaya

Using fine-resolution satellite imagery from multiple satellite data products, we assessed the change in forest cover of a state-managed Reserve Forest (RF) located in India’s Eastern Himalaya biodiversity hot-spot. 4.6% of forest cover was lost from Papum RF between 2013 and 2017 at the rate of 8.2 km2 year–1. Three species of hornbills: Great Hornbill Linnaeus, 1758, Wreathed Hornbill (Shaw, 1811) and Oriental Pied Hornbill (Shaw, 1808), that are functionally important are found here with nesting habitat in the areas affected by illegal logging. Therefore, we assessed the habitat loss within a 1 km radius around 29 nest trees. From 2011 to 2019, forest cover declined from 38.55 km to 21.94 km around these hornbill nest trees. Illegal logging is the main driver that is depleting forest cover within this important bird area. Our results highlight the ongoing threats to biologically-rich forests and the need for urgent measures to halt this loss. We suggest that this study has practical implications for the monitoring and governance of state-managed forests in Arunachal Pradesh.Buceros bicornisRhyticeros undulatusAnthracoceros albirostris22

Vertebrate prey handling in the Indian Grey Hornbill Ocyceros birostris (Aves: Bucerotiformes: Bucerotidae)

Most hornbills are omnivorous, but there are few specific records of how vertebrate prey are handled by hornbills, particularly in Asia. I describe an observation of a pair of Indian Grey Hornbills Ocyceros birostris handling a large vertebrate prey item (Garden Lizard Calotes versicolor) which included both manipulation (crushing) in the bill and repeated wiping on the branch of a tree, the latter technique undescribed for this or other species of hornbill. Likely reasons for this behaviour are discussed.

How far do Asian forest hornbills disperse seeds?

Biotic seed dispersal of plants is a complex phenomenon that is influenced by multiple seed disperser species with implications for plant fitness and range expansions. While inter-species variation has been well-studied, the importance of incorporating intraspecific variation in seed dispersal is increasingly being acknowledged. We compared seed dispersal patterns of breeding and non-breeding great hornbills Buceros bicornis and a breeding wreathed hornbill Rhyticeros undulatus by combining data on fruiting tree visitations, gut passage time and movement data from tagged hornbills. Seed dispersal probability at nest trees (by breeding males) was low (<12%) suggesting that males scatter-disperse seeds, unlike breeding females that deposit seeds below nest trees. Median seed dispersal distance of great hornbills was 294 m and 254 m in the breeding and non-breeding season respectively, and, the distribution tail was shorter for breeding birds (2.5 km) than non-breeding birds (13 km). The median and maximum seed dispersal distance by the wreathed hornbill was 1.35 km and 11 km respectively. This study highlights intraspecific variation in seed dispersal patterns across sexes and breeding and non-breeding male hornbills and potential variation between two hornbill species. This is the first study that estimates long-distance seed dispersal by Asian hornbills.

When the seeds sprout, the hornbills hatch: understanding the traditional ecological knowledge of the Ibans of Brunei Darussalam on hornbills

BackgroundHornbills 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.MethodWe 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.ResultsThe 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.ConclusionThere 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.

VARIASI INTERSPESIFIK JULANG (AVES: BUCEROTIDAE) INDONESIA BERDASARKAN GEN CYTOCHROME-B DNA MITOKONDRIA

Genetic information of Indonesian hornbills (Julang) is still limited. We sequenced the cytochrome b gene of three hornbill species (Rhyticeros undulatus, R. plicatus, and Aceros cassidix) to explore their genetic variation, distance, and phylogenetic. Nine blood samples for Cyt b from three hornbill species were isolated with Dneasy® Blood and Tissue Kit base on Spin-Column Protocol, Qiagen. SNP, genetic distance, and phylogeny were calculated by MEGA 6.0 software. This study was found variations in the Cyt b gene sequence (849 bp) between three species Indonesian Julang. Rhyticeros undulatus had the most SNP compared to R. plicatus and Aceros cassidix. Substitution of synonyms is more common than substitution of synonyms and transition substitution frequency tends to be much higher than transversion substitution. The three species of Indonesian Julang were markedly separate with an average genetic distance of 5.25%. and separated with the outgroup species at a genetic distance of 9.43%. Cytochrome b sequence genes from these three hornbill species are novel for identifying and classifying hornbills, and could be applied to prevent illegal poaching and conservation management in Indonesia.

Avifauna in Logged-Over Forest of Upper Baleh, Sarawak

Commercial logging is a major economic activity in the Upper Baleh catchment, Sarawak, so logged-over forest is the dominant forest type there. Avifauna survey was conducted in the logged-over forest of Upper Baleh in November 2015 as part of the Upper Baleh Heart of Borneo Expedition. The objective of the survey was to collect baseline data on the avifauna species that inhabit the study area, their conservation status and feeding guilds. Both mist-net and observation method were used. A total of 95 species of birds was recorded: 36 species via mist-nets and 69 species via observation. Little spiderhunter was the dominant species, accounting for 33% of mist-netted bird. Seven species are Totally Protected including six species of hornbills and a Great Argus Pheasant, while 18 other species are Protected under the Sarawak Wild Life Ordinance 1998. The majority of the birds are insectivorous (55.8%), foraging either at ground level (babblers), along the tree trunks or branches (woodpeckers) or at the canopy (flycatchers). Omnivorous birds, which feed on two or more types of diet, accounted for 48.4% of the avifauna species recorded and these include bulbuls and hornbills. The diverse community of bird, including the protected species, makes the area an attractive birding destination for visitors since now part of the catchment has been gazetted as a national park. Avifauna’s role as pollinating and dispersing agent will help the logged-over forest to recover.&#x0D; Keywords: conservation status, feeding guilds, Heart of Borneo, logging roads

Cavity Management Enhanced the Allelic Distribution of Great Hornbills in Eastern Khao Yai National Park

Khao Yai National Park, covering an area of 2,168 km2, is very rich in wildlife. The park includes mainly monsoon evergreen forests inhabited by four species of hornbills, namely Anthracoceros albirostris, Buceros bicornis, Ptilolaemus austeni and Rhyticeros undulatus. Among these species, Great Hornbills, B. bicornis, are the largest birds and require the most in terms of quantity and quality of natural resources. They require very large cavity which is in short supply in the wild. The western part of the park supports a high population of Great Hornbills while in the eastern part has low density. From 2009, the study has been expanded to cover the eastern part. Following seven consecutive years (2009‒2015) of nest management, we studied the uses of nests with 4 microsatellites DNA markers specific for each allele of Great Hornbills. This study is to examine non-invasively the 49 DNA samples from mainly tailed feathers. We collected DNA from the shed feathers at or near the nests from Eastern and Western Khao Yai. The population structure analysis revealed by microsatellites markers, showed the inbreeding coefficient (Fis) of the local hornbills of Western Khao Yai improved from 0.45 in 2009 to -0.028 in 2015 with great genetic diversity. In 2014, these hornbills introduced 6 of 9 alleles into the Eastern Khao Yai (locus Bbi 3). Data showed the population connectivity between the two subpopulations. The gene flows potentially increase between the west and the east. Nonetheless, heterozygosity of Great Hornbills in the Eastern Khao Yai significantly improved from HObs = 0.615 to 0.750. Results also showed the availability of suitable nest cavities attracted hornbills from the western to eastern Khao Yai. This molecular approach indicates that the nest cavity management is one of the important strategies to secure the longterm survival of hornbills.

Spatial Distribution and Habitat Choice of Two Sympatric Species of Hornbills in Vidarbha, Maharashtra, Central India

Vidarbha is the eastern region of Maharashtra state, lies on the northern part of the Deccan Plateau and has the Satpuda Hill ranges to the north. Vidarbha region has two species of hornbills, i.e., Indian Grey Hornbill Ocyceros birostris and Malabar Pied Hornbill Anthracoceros coronatus. The Malabar Pied Hornbill is now listed as Near Threatened by the IUCN. Data collected from three methods is used in this paper, data collected during field surveys by the authors, compilation of published bibliographic data of previous sightings and by compilation of data from citizen science forums. The study indicates that the spatial distribution of the two sympatric hornbill species is largely influenced by fragmentation of well protected forests due to agricultural expansion and urbanisation. The Malabar Pied Hornbill prefers and is mainly confined to the protected areas like tiger reserves and wildlife sanctuaries. Whereas, the Indian Grey Hornbill prefers fragmented forests and large gardens in urban areas and is also found in protected forested areas overlapping with the Malabar Pied Hornbill.

Camera Trapping: A Tool to Study Hornbills?

Of the 57 species of hornbills in the world, 25 species are recorded in Africa, 32 species are recorded in Asia but only eight occur in Borneo. However, due to logging, hunting and forest fragmentation, the Bornean lowland forest often does not host all the species at once. The study of using remotely triggered infrared cameras in avifauna research is commonly used for medium to large terrestrial mammals, and birds, such as pheasants. Documentation of rare and new species presence records, behavioural studies, and activity patterns could also be included in the application of camera trapping in the study of birds. From the 304 camera trapping sites distributed throughout Sarawak, two species of hornbills were photographed during the study period: the White-Crowned Hornbill Berenicornis comatus and Asian Black Hornbill Anthracoceros malayanus. These images represent approximately 0.01% (34 out of 29,618 images) of the overall independent photos from a total effort of 29,470 camera trapping nights. Although data are insufficient to support the activity overlap between these two species, some baseline information on the behaviour of hornbills has been observed.

Distribution of Hornbills in western Sarawak and the Way Forward for Their Conservation in Sarawak

There are eight species of hornbills in Borneo. However, little is known on their distribution and ecology in western Sarawak. Their large size requires habitats that consist of large forest patch with large fruiting trees for feeding and nesting. They have an important ecological niche as seed dispersers throughout the tropical rainforests of South East Asia. This study briefly describes the distribution of hornbills in Totally Protected Areas (TPA) within western Sarawak based on data collected by Sarawak Forestry Corporation from 2013‒2016. We discuss the hornbill species distribution and the species area relationship within western Sarawak. The Rhinoceros Hornbill (Buceros rhinoceros) recorded the highest occupancy value (psi) and probability of detection (p), followed by the Black Hornbill (Anthracoceros malayanus) and the Bushy-crested Hornbills (Anorrhinus galeritus). The Helmeted Hornbills (Rhinoplax vigil) appears to occur in fewer TPA within western Sarawak. A long-term conservation plan is required to ensure the sustainability of the hornbill population through extending protected areas and connecting forest patches. In light of this, the research and conservation needs for these species in Sarawak are highlighted to ensure their long-term survival in the wild.

Community Structure of Hornbills in an Oil Palm Landscape in East Kalimantan, Indonesia

Conserved land in human dominated landscapes such as oil palm plantations provide habitat for many animal taxa including hornbills. The aim of the study is to quantify species richness, distribution, population size and sex ratio of hornbill community in oil palm landscapes with retained native forest patches. Ecological sampling was conducted in an oil palm plantation in East Kalimantan, Indonesia. Birds were observed using fixed radius point count method. We found that there were six hornbill species belonging to four genera of Bucerotidae including Helmeted Hornbill, Rhinoceros Hornbill, Wreathed Hornbill, Wrinkled Hornbill, Black Hornbill and Oriental Pied Hornbill that occurred in the study site. Population density varied among species ranging from 0.17 to 4.72 individual per km2 in 2012 and 0.34 to 3.35 individual per km2 in 2013. Rhinoceros Hornbill was the most abundant species observed in one location with highest number of individual per group of about 21 individuals during flocking. Sex ratio (M:F) was ranged from 0.31 to 0.95. The dispersion of hornbill species was generally random. Our results show that retention of forest patches on oil palm plantations can help to maintain the diversity and abundance of hornbills in the region.

From Pre-Brookes to Hot, Flat and Crowded World: Are Changes in Indigenous Knowledge, Beliefs and Practices Seriously Affecting Hornbills Conservation?

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, known as the traditional ecological knowledge. Such influence has, over time developed into acceptable cultural and traditional identity of indigenous people. Today, changes in the political and socio-economic development, driven by the flattening, crowding and warming of the world have devoured open space and tropical rainforest of the world. The impacts, in turn to some extent had disrupted ecosystems and depleted 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 socio-economic conditions.

Distribution of Hornbills and Important Hornbill Landscapes - Setting Site Conservation Priorities for Peninsular Malaysia

Malaysia is an important hornbill range country in Asia supporting a total of 10 hornbill species. Malaysia ranks second (collectively with Myanmar and the Philippines) after Thailand and Indonesia (both 13 species respectively) in terms of hornbill diversity per country. Within Malaysia, all 10 species has been recorded in Peninsular Malaysia whereas Sabah and Sarawak have 8 species each. The Great Hornbill Buceros bicornis and Plain-pouched Hornbill Rhyticeros subruficollis do not occur in Borneo. Despite being iconic tropical forest birds, our understanding of its local distribution status, ecology and biology remains limited. In this paper, we conducted a broad examination of the hornbills’ distribution in Peninsular Malaysia based on more recent information gleaned mostly from grey literature e.g. birding trip reports, scientific expedition reports, department annual reports, selected Facebook birding group postings, proceedings, bird databases (MNS Bird-I-Witness) etc. Information from primary literature e.g. local/regional journals were also taken into account where available. The purpose of this exercise is two-fold, (1) to update our knowledge post-Wells (1999) about hornbill distributions in Peninsular Malaysia in light of continuing deforestation and habitat degradation and (2) identify Important Hornbill Landscapes (IHL) in need of protection and conservation to preserve viable hornbill populations.

Inset Tree Cavity Nesting Site: A Method of Cavity Creation for Oriental Pied Hornbill (Anthracoceros albirostris)

Populations of most hornbill species continue to decline due to hunting and habitat degradation. Hornbills rely exclusively on tree cavity sites for nesting and incubation as part of their breeding behaviour. Since they are not able to excavate on their own, they require the presence of existing tree cavities. Additionally, the natural cavity size suitable for species such as Oriental Pied Hornbill requires mature trees in which cavities have formed within larger diameter wood. In disturbed forests, or in the urban context, the availability of large trees with potential nesting sites is even more limited. Man-made nesting boxes have been considered as alternatives to help increase the hornbills’ nesting options, but low nest productivity have been reported. This paper explores the practicality of using human assistance in creating inset tree cavities through the use of chainsaws and bore-cutting techniques to assist nesting of the Oriental Pied Hornbill (Anthracoceros albirostris) in Piasau Nature Reserve, an urban forest reserve in the state of Sarawak, Malaysia. These cutting and cavity excavation methods have been used successfully to resemble the natural process of cavity development for other secondary tree cavity nesting species.

Future Outlook of Building Indonesia National Hornbill Monitoring Protocol

Hornbills (Bucerotidae) are endangered bird species and current trade issues become major threats which surpass the information available on hornbill population. Differences in survey protocol from various regions in Indonesia may lead to acquisition of low quality data. Using Distance Sampling data from Sumatra and Sulawesi gathered from various projects, we examined different protocols for hornbill population estimation. The results demonstrated that most of hornbill species are distributed in the undisturbed forests of protected areas. The higher the efforts of the survey, the more observations are obtained. Density estimations were similar for Sumatran species except for the Rhinoceros Hornbill. Density estimation for Sulawesi hornbills was inconsistent, probably due to difference in site (mainland versus island). Line transect seemed more effective to achieve detections compared to point count suggest that detection at initial location may be violated in point count. These results suggested that understanding distance sampling is important in standardising protocols. Additionally, improvement on detections and hornbill identification is needed. Thus, training is crucial to ensure that a national hornbill monitoring protocol can be established and applied throughout Indonesia.

Wreathed Hornbill (Rhyticeros undulatus) in Mount Ungaran Central Java: Status and Factors that Threaten Its Existence

Mount Ungaran in Central Java is one of the Important Birds Areas (IBA) in Indonesia where one of the Hornbill species, Wreathed Hornbill (Rhyticeros undulatus) is found. Based on the IUCN 2016, Wreathed Hornbill has been listed as Least Concern (LC) and listed in Appendix II of the CITES. In order to conduct preservation and in-situ conservation planning of Wreathed Hornbill scientific data on ecology is needed. Therefore, the research on the Wreathed Hornbill in Mount Ungaran has been planned since 2010‒2016. The results include species identification, early population and distribution, daily behaviour, habitat profile, nest-site characteristics, feeding behaviour, food consumed, habitat suitability and threats. While study on the dynamics of the home range of Wreathed Hornbill in Mount Ungaran is still ongoing. The implementation of this research is jointly pursued with the Forest Department, Natural Resources Conservation Center (BKSDA), Perhutani Central Java, Indonesia Hornbill, and LIPI (Indonesian Institute of Sciences), and IBBS (Indonesian Bird Banding Scheme).

Do People Care? The Awareness of Local Communities in Miri Towards Hornbills at Piasau Nature Reserve, Sarawak

Hornbills are a major attraction for ecotourism at the Piasau Nature Reserve, near Miri, Sarawak. Hornbills, in general, are believed to play important ecological roles in tropical forests, especially as agents of seed dispersal. At the Piasau Nature Reserve, the Oriental Pied Hornbill (Anthracoceros albirostris) is the most popular species and has caught the attention of some conservationists. This survey was conducted to investigate the perception of local communities in the Miri area about hornbills at this Park. Our survey suggests that the Miri residents are positive towards hornbill conservation at this park after the case of a Oriental Pied Hornbill called Faridah that was killed. More than half of our respondents are aware of the existence of this hornbill species at Piasau.

Sumatran Hornbills in Fragmented Forest Areas in Oil Pam Plantation in South Solok, West Sumatra

A study on hornbill populations in fragmented forest areas within oil palm plantations in Tidar Kerinci Agung (TKA) Company, West Sumatra was carried out from July to August 2015 in 60 Hectare fragmented forest areas. The objective of this study was to document hornbill species richness using the transect method on three main lines along two km and using call recognition for population census of hornbill. During the study, we recorded 82 individuals of eight species after 60 km walk. We encountered using two methods (Sighting and Calls Methods); Anorrhinus galeritus twenty-one encounters, Berenicornis comatus single encounter, Rhabdotorrhinus corrugatus two encounters, Rhyticeros undulatus two encounters, Anthracoceros malayanus sixteen encounters, Anthracoceros albirostris seven encounters, Buceros rhinoceros thirty-one encounters and two encounters of Rhinoplax vigil.