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Observations at a nest of Helmeted Hornbill Rhinoplax vigil in Borneo, Malaysia
Abstract
Little is known about the nesting behaviour of the Helmeted Hornbill Rhinoplax vigil because it occurs in low numbers and nests are difficult
to locate. The nest cavity is usually high and hidden amidst thick foliage and the cavity’s opening is inclined upwards, making it hard to
see from the ground. A nesting pair of Helmeted Hornbills was observed in the Kinabatangan Wildlife Sanctuary between 2013 and 2017.
We sought to determine the nesting period and associated behaviour, and to identify the type and amount of food provided to the female
and chick over the nesting cycle. The nest was located inside the nub of a broken branch of a Shorea pauciflora tree, 37 m up on the trunk.
The pair began nesting in May, in the drier months, and the single chick fledged in November the same year. The pair and the fledged
young stayed together for at least six months. The male made a maximum of 11 visits per day to bring food to the nest midway through the
breeding period. Food brought to the nest consisted of mainly figs, including Ficus stupenda, F. benjamina, F. stricta and F. crassiramea. The
adult Helmeted Hornbills delivered stick insects, beetles and praying mantis, while the chick itself caught and consumed a giant millipede
at the nest entrance. The specific fig diet and nest cavity preferences make the species extremely vulnerable to environmental changes
caused by logging and agricultural expansion. The added pressure from hunting it for casques may be driving it to extinction. Therefore
we recommend that their nests be located and offered protection by local authorities and communities through nest adoption schemes.
... Selective living requirements of Helmeted Hornbills makes them occur in only particular locations depending on food supply, secutiry, and comfortability which support the habitat suitability. Disconsertingly, little is known about the basic biology and ecology of the species (Kaur et. al., 2019). It extends into adjacent mature secondary forest, but avoids open areas, disturbed forest and peat swamps (Kinnaird & O'Brien, 2007;Lum & Poonswad, 2005;As the availability of suitable nest sites plays a major role in population recruitment of cavity-nesters (Cody 1985). The Helmeted Hornbill has the most specialised diet of any hornbi ...
Helmeted hornbill (Rhinoplax vigil) is a protected wildlife in Indonesia according to enactment no. 5, 1999 about Conservation of Natural Resources and its Ecosystems and Government Regulation no. 9, 1999 about plant and wildlife preservation. Helmeted Hornbill habitats spread in five country regions: Myanmar, Thailand, Malaysia (Malayan Peninsula and Serawak), Brunei, and Indonesia (Sumatra and Borneo). Silokek Geopark which located in Sijunjung Regency, West Sumatra Province, Indonesia is an identified location of Helmeted Hornbill habitat existence. Beside its uniqueness in physics, this bird also have an ecological function as seed dispersal in nature. The utilization of Remote Sensing (RS) technology and and Geographic Information System (GIS) is highly useful in identification the Helmeted Hornbill habitat distribution in this research. Geographic dateset used in this research are Landsat OLI 8 imagery, Shuttle Radar Topographic Model (SRTM), Coordinate points of Helmeted Hornbill existence and location assesment, and other dataset related to administration boundary in Silokek Geopark. This research aims to find conservation priority zone of Helmeted Hornbill in Silokek Geopark. By utilizing Maximun Entropy (MaxEnt) algorithm with finding points and location assessment, we can determine the distribution of Helmeted Hornbill habitat in Silokek Geopark based on habitat likeness. This research produces the model of conservation priority zones in geopark silokek which are distributed in hilly protected forest area and the distributions are concentrated in the center and noth east part of our researc area. This model is highly influenced by forest texture (25.7%), distance of patches (24.3%), and distance of settlement.
Helmeted hornbills (Rhinoplax vigil, J.R. Forster, 1781) are ‘Critically Endangered’ due to illegal hunting for their casques which are carved and traded for ornamental purposes. DNA species identification techniques can aid enforcement efforts, and validated wildlife forensic techniques for the species identification of R. vigil are needed. Here we tested multiple methods for sampling and extracting DNA from R. vigil casques and a validated a previously published assay using cytochrome B (cytB) primers to identity species and origin of traded casques. Phenol-chloroform: isoamyl alcohol extractions resulted in samples with higher quantity and quality of DNA than those extracted using the commercial Qiagen DNeasy blood and tissue kit. Samples collected from the caudal side of the casque yielded higher DNA quantity and quality than rostral and lateral sides, regardless of sampling method. We then assessed the repeatability, reproducibility, robustness, sensitivity, specificity, and phylogenetic resolution of a previously published species identification assay. We confirm the ability of this method to phylogenetically distinguish between R. vigil and closely related hornbills with high bootstrap support (99%). We also report the first genetic evidence of illegally traded R. vigil in Hong Kong using confiscated casques and provide more reference samples of R. vigil for future work. Overall, we provide multiple protocols for sampling and extracting DNA, and a validated species identification assay for amplifying DNA from R. vigil casques with potential to aid law enforcement in illegal wildlife crimes.
Hunted wildlife can often be used to answer questions about wild individuals. Sex ratios of hunted individuals can be important for understanding changes in population demographics and viability. Here we determined the sex ratio of the illegally hunted helmeted hornbill Rhinoplax vigil, a critically endangered species from Southeast Asia, to examine their vulnerability to hunters. Using casques seized in Hong Kong SAR between 2012 and 2016, we identified the sex of seized individuals using morphological and molecular methods as well as discriminant analysis. As R. vigil females can spend up to 6 months of the year sealed into tree cavity nests, they are reliant on males for food. The unique breeding ecology of this elusive species means that males are more likely to be observed than females throughout the year. These behavioural differences mean that there are several potential outcomes which may be observed in the sex ratio of the seized casques, depending on hunting strategies. Our results suggest that sex identification is possible via visual inspection of the gular skin colour and beak‐tip markings, but when these are not available, genetic methods or morphological measurements can be used. Our findings also indicated a primarily male‐biased sex ratio across the seizures; however, females, as well as juveniles, were also present in seizures. Although removing one sex from the wild can cause shifts in demographic dynamics over time, illegal and unsustainable hunting of any measure of a critically endangered species will ultimately heighten its risk of extinction. These methods and results are useful to conservationists and researchers interested in further study of hornbill populations and their viability and are ultimately important for the conservation and management of this critically endangered species. Helmeted hornbills Rhinoplax vigil are critically endangered due to illegal hunting for their solid casques which can be carved similarly to elephant ivory. Analysis of the sex ratio and age of seized casques reveals that males and females, adults and juveniles are all targeted for the trade.
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