Argusianus Research Articles

Loss of Sunda clouded leopards and forest integrity drive potential impacts of mesopredator release on vulnerable avifauna

Amongst the unintended consequences of anthropogenic landscape conversion is declining apex predator abundance linked to loss of forest integrity, which can potentially re-order trophic networks. One such re-ordering, known as mesopredator release, occurs when medium-sized predators, also called mesopredators, rapidly increase in abundance following the decline in apex predator abundance, consequently reducing the abundance of mesopredator prey, notably including terrestrial avifauna. We examine the cascading impacts of declining Sunda clouded leopard abundance, itself consequent upon a reduction in forest integrity, on the mesopredator community of Sabah, Malaysia, to determine whether the phenomenon of mesopredator release is manifest and specifically whether it impacts the terrestrial avifauna community of pheasants and pittas. To explore this trophic interaction, we used a piecewise structural equation model to compare changes in the relative abundance of organisms. Our results suggest that loss of forest integrity may have broad impacts on the community and trigger mesopredator release, the two acting additively in their impact on already vulnerable species of terrestrial avifauna: a result not previously documented in tropical systems and rarely detected even on a global scale. The limiting effect that the Sunda clouded leopard has on the Sunda leopard cat could illuminate the mechanism whereby mesopredator release impacts this system. Both Bulwer's pheasant and pittas appear to be significantly impacted by the increase in Sunda leopard cats, while the great argus pheasant shows similar compelling, although not statistically significant, declines as Sunda leopard cats increase. The inverse relationship between Sunda clouded leopards and Sunda leopard cats suggests that if a mesopredator release exists it could have downstream consequences for some terrestrial avifauna. These results suggest the under-studied interface between mammalian carnivores and avifauna, or more broadly species interactions in general, could offer important conservation tool for holistic ecosystem conservation efforts.

Small vertebrates in CFS ecological corridor (D-PL1: Lojing - Sungai Brok - Sungai Betis Forest Reserves) Kelantan

Small vertebrate surveys were carried out in the Sungai Brok and Sungai Betis Forest Reserves. The Central Forest Spine (CFS) initiative has recognised these forest reserves as part of Kelantan's important ecological corridors, known as D-PL1. The surveys were conducted from July to September 2019. This study aims to identify and update the checklist of small vertebrates in the selected forest reserves. One hectare plot was established in each forest reserve for this study. Traps were used to capture and document these vertebrates, including 100 collapsible cage traps, three harp traps, 10 mist nets, and 25 pitfall traps deployed at each sampling site. In addition, the surveys also carried out active searches and direct observations. Overall, this study recorded 83 species from 38 families of small vertebrates. With the total, small mammals comprise of 13 spp. from six families, birds (53 spp. from 24 families), and herpetofauna (17 spp. from eight families) were recorded during this study. Ten small mammal species are recorded as additional species for D-PL1. Birds and herpetofauna recorded 38 and eight additional species to the existing checklist of D-PL1, respectively. Based on the IUCN Red List of Threatened Species (Version 3.1), this study recorded three threatened species namely Great Argus (Argusianus argus), Great Slaty Woodpecker (Mulleripicus pulverulentus), and Grey-cheeked Bulbul (Alophoixus tephrogenys) in D-PL1. This information is likely to support stakeholders in formulating a management strategy for the forest mosaics in the corridor, which will continue to serve as an essential habitat for small vertebrates.

Wrinkle nanostructures generate a novel form of blue structural color in great argus flight feathers

Currently known structural colors in feathers are caused by light scattering from periodic or amorphous arrangements of keratin, melanin, and air within barbs and barbules that comprise the feather vane. Structural coloration in the largest part of the feather, the central rachis, is rare. Here, we report on an investigation of the physical mechanisms underlying the only known case of structural coloration in the rachis, the blue rachis of great argus (Argusianus argus) flight feathers. Spectrophotometry revealed a reflectance peak at 344nm that is diffuse and well matched to the blue and UV-sensitive cone sensitivities of this species' visual system. A combination of electron microscopy and optical modeling confirmed blue coloration is generated by scattering from amorphous wrinkle nanostructures 125nm deep and 385nm apart, a new avian coloration mechanism. These findings have implications for understanding how novel courtship phenotypes arise through evolutionary modification of existing ontogenetic templates.

Does shading on great argus Argusianus argus feathers create a three-dimensional illusion?

Many animals use shading to infer the three-dimensional (3D) shape of objects, and mimicking natural shading patterns can produce the illusion of 3D form on a flat surface. Over 150 years ago, Charles Darwin noted that the ocelli (eyespots) on the feathers of the great argus Argusianus argus, when held vertically during courtship displays to females, were perfectly shaded to resemble 3D hemispheres to human viewers. We tested whether these ocelli appear 3D to birds by training chickens Gallus gallus domesticus to select images of either convex or concave shapes using shading cues, and then presenting them with images of great argus ocelli. Chickens successfully learned how to discriminate between convex and concave shapes, and treated the great argus pheasant ocelli in the same way as convex training stimuli. Our findings are consistent with previous studies that birds can perceive 3D shape from shading cues in a similar manner to humans. The perception of great argus ocelli as consistent with 3D shape by avian viewers suggests that shape illusions can play a role in male courtship.

Short Communication: Taxonomic status of Great Argus (Argusianus argus) Sumatra and Borneo based on cytochrome B gene

Abstract. Ericca C, Tjong DH, Roesma DI, Novarino W, Syafullah, Janra MN, Aandrean. 2022. Short Communication: Taxonomic status of Great Argus (Argusianus argus) Sumatra and Borneo based on cytochrome B gene. Biodiversitas 23: 4670-4676. Great Argus (Argusianus argus) belongs to the bird family Phasianidae. Currently, there are two Great Argus subspecies: A. argus argus in Sumatra and the Malay Peninsula, and A. argus grayi in Borneo. Therefore, this study aims to determine the taxonomic status of Great Argus across its distribution region. Phylogenetic relationships between two Great Argus subspecies were inferred in this study using the mitochondrial cytochrome b gene. DNA was isolated, amplified, and sequenced from the feathers of Great Argus sampled from Kinantan Wildlife and Cultural Park, Bukittinggi, West Sumatra, Indonesia. Phylogenetic relationships were analyzed with Maximum Likelihood methods. The phylogenetic trees show monophyletic relationships between Sumatran Great Argus subspecies. Analysis result shows that Bornean Great Argus has a 3.26-3.80% genetic distance from the Sumatran Great Argus based on analysis using the 789 bp of cyt b gene. Based on the result, it also refers that Bornean Great Argus and Crested Argus (Rheinardia ocellata), have a close relationship, indicated by low genetic distances (5.87-6.73%). This study suggests that Bornean Great Argus is genetically different from Sumatran Great Argus.

Hydropower reservoir reduces Great Argus Argusianus argus density in proximity to its shore

Summary Habitat degradation due to hydropower development within protected areas has a marked negative effect on resident wildlife species. However, efforts to develop appropriate conservation and management plans are hampered by a general lack of quantitative information and a poor understanding of relevant ecological constraints. Great Argus Argusianus argus, a large galliform species sensitive to habitat degradation, can reflect the impacts of the Chiew Larn reservoir in southern Thailand on local wildlife. Great Argus abundance in the remaining lowland areas of Khlong Saeng Wildlife Sanctuary (KSWS) was estimated using line transects along the Chiew Larn reservoir edges and in the forest interior between February and April 2017. The population estimate for KSWS was 108 individuals (95% CI: 41–272) based on the sampled area of 18.06 km2, with a density estimate of 5.9 calling males/km2. The abundance increased with increased distance from the reservoir shoreline, which might be related to the high level of direct and indirect human disturbance close to the hydropower reservoir.

Avifauna in the Wehea-Kelay Landscape, East Kalimantan, Indonesia

Wehea-Kelay landscape is an unprotected area, located on the eastern part of Borneo Island. It is managed by 7 unit managements, which were mostly timber companies. We compiled and collated our avifauna data with previous studies. We recorded 273 bird species belonging to 60 families during field work. 61 species were protected based on Indonesian regulations. Among of them were threatened species with small population such as Great argus Argusianus argus, Storm’s stork Ciconia stormi, and Helmeted hornbill Buceros vigil. Although Wehea-Kelay is dominated by timber concessions, the landscape can still provide habitat for many species of bird. Nevertheless, anthropogenic pressures i.e. illegal hunting have increased and become a threat for birds particularly commercially traded species such as Leafbirds Chloropsis spp, White-rumped Shama Copsychus malabaricus, Common hill myna Gracula religiosa, and also Helmeted hornbill Buceros vigil.

Not by the light of the moon: Investigating circadian rhythms and environmental predictors of calling in Bornean great argus.

Great argus pheasants are known for their elaborate visual mating displays, but relatively little is known about their general ecology. The use of passive acoustic monitoring-which relies on long-term autonomous recorders-can provide insight into the behavior of visually cryptic, yet vocal species such as the great argus. Here we report the results of an analysis of vocal behavior of the Bornean great argus (Argusianus argus grayi) in Sabah, Malaysia, using data collected with 11 autonomous recording units. Great argus regularly emitted two call types, the long call and the short call, and we found that although both call types were emitted throughout the day, the short calls were more likely to occur during the morning hours (06:00-12:00LT). Great argus were less likely to call if there was rain, irrespective of the time of day. A substantial portion of calls at our site (~20%) were emitted between the hours of 18:00-06:00LT. We found that for nighttime calls, calling activity increased during new moon periods and decreased during periods of rain. We attribute the negative influence of rain on calling to increased energetic costs of thermoregulation during wet periods, and propose that the influence of the lunar cycle may be related to increased predation risk during periods with high levels of moonlight. Little is known about the behavioral ecology of great argus on Borneo, so it is difficult to know if the results we report are typical, or if we would see differences in calling activity patterns depending on breeding season or changes in food availability. We advocate for future studies of great argus pheasant populations using paired camera and acoustic recorders, which can provide further insight into the behavior of this cryptic species.

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.
 Keywords: conservation status, feeding guilds, Heart of Borneo, logging roads

Assessing the spatiotemporal interactions of mesopredators in Sumatra's tropical rainforest.

Co-occurrence between mesopredators can be achieved by differentiation of prey, temporal activity, and spatial habitat use. The study of mesopredator interactions is a growing area of research in tropical forests and shedding new light on inter-guild competition between threatened vertebrate species that were previously little understood. Here, we investigate sympatry between the Sunda clouded leopard (Neofelis diardi) and Asiatic golden cat (Pardofelis temminckii) living in the Sumatran rainforests of Indonesia. We investigate: i) spatial overlap of predator-prey species using a combination of single-species occupancy modelling and Bayesian two-species modelling, while controlling for the possible influence of several confounding landscape variables; and, ii) temporal overlap between mesopredators and their shared prey through calculating their kernel density estimate associations. From four study areas, representing lowland, hill, sub-montane and montane forest, 28,404 camera trap nights were sampled. Clouded leopard and golden cat were respectively detected in 24.3% and 22.6% of the 292 sampling sites (camera stations) and co-occurred in 29.6% of the sites where they were detected. Golden cat occupancy was highest in the study area where clouded leopard occupancy was lowest and conversely lowest in the study area where clouded leopard occupancy was highest. However, our fine-scale (camera trap site) analyses found no evidence of avoidance between these two felid species. While both mesopredators exhibited highest spatial overlap with the larger-bodied prey species, temporal niche separation was also found. Clouded leopard was more nocturnal and, consequently, had higher temporal overlap with the more nocturnal prey species, such as porcupine and mouse deer, whereas the more diurnal golden cat had higher overlap with the strictly diurnal great argus pheasant. The Bayesian two species occupancy modelling approach applied in our study fills several important knowledge gaps of Sumatra’s lesser known mesopredators and provides a replicable methodology for studying interspecific competition for other small-medium sized carnivore species in the tropics.

AKTIVITAS KUAU RAJA (Argusianus argus Linnaeus, 1766) PADA MATING RING DI HUTAN KONSERVASI KALAWEIT SUPAYANG, SOLOK, SUMATERA BARAT

A behavioral study of Great Argus Pheasants (Argusianus argus Linnaeus, 1766) at their mating ring has been done from October 2015 to January 2016 in The Kalaweit Supayang Conservasion Forest, Solok, West Sumatra. The purpose of this research is to know about activities of Great Argus Pheasant and how their activities done. Field observation in the mating ring was conducted using ten video camera traps for three months at their mating ring. Those cameras were activated for 60 seconds per session by 10 seconds intersession intervals. Behavioral data were tabulated from video records using continuous recording method. There were eight activities of Great Argus Pheasant at their mating ring which divided into individual and pairmate activities. The individual activities of male included clearing, walking, vigilance, feeding, grooming, resting, and calling. While female activities included resting, grooming, and walking. Activity with pairmate was dancing where male performed dancing only in the present of female. Male spent 26 times longer than females appeared at the mating ring. The peak activities at mating ring was in the morning between 7:00 and 8:00 am.

Effect of landscape variables on the long-term decline of Great Argus in the rainforest of Southern Thailand

SummaryIn Thailand, as for most of South-East Asia, large vertebrates are declining rapidly due to habitat degradation and increasing hunting pressure. Once relatively common in the evergreen forest of Southern Thailand, the Great ArgusArgusianus argusis currently limited to a few populations, whose status is currently unknown. In this study we investigated changes in Great Argus abundance over the past 13 years in Hala-Bala Wildlife Sanctuary. Our aim was to estimate and compare the abundance and density of this species from an earlier two-year survey in 2001–2002 and ours in 2014, and to assess the effect of landscape change on its status of the species. We conducted surveys from March to August 2014 during the breeding season. We placed point counts that overlapped the line transects from the 2001–2002 survey. The results indicated a decline of > 35% in mean abundance from 2001 to 2014. In addition, male abundance has shifted and is now positively related to distance from the forest edge. High levels of human disturbance close to the forest edge may have resulted in the birds moving to the core of the forest, suggesting a need to increase protection and management of forest edge areas. In common with other studies of large vertebrates, our results confirm the importance of long-term studies to highlight the negative effects of human disturbance.

Use of lookout watches over forest to estimate detection, dispersion and density of hornbills, Great Argus and diurnal raptors at Bala forest, Thailand, compared with results from in-forest line transects and spot maps

SummaryWe estimated detection, dispersion and density of 10 hornbill, one pheasant and nine diurnal raptor species at Bala forest, southern Thailand, throughout 2004. We conducted 620 1-h lookout watches over the forest canopy from 14 elevated locations along 13.1 km of paved road through Bala, during which we recorded all detections and movements of target species. For a further 619 h, we also recorded all in-forest detections of target species during excursions along and adjacent to the road. Our records covered all months of the year and hours of the day, enabling us to estimate seasonal and diurnal patterns of detection for each target species. We found significant seasonal and diurnal variation for all commoner species in rates of overall detection, visual versus aural detection, and vociferousness. We related most monthly variation to the timing of nesting and most hourly variation to aspects of the behavioural ecology of each species. We used three techniques to estimate dispersion and density for each species, two from lookouts based on our counts of individuals or breeding units per unit area observed, and one from spot maps of core breeding units within 500 m of the road. Differences in our estimates of density varied within and between species, but were mostly lowest for the mean number of individuals detected from lookouts and highest for the maximum of breeding units, whether from lookout detections or core area counts from spot maps. These ranges of densities and their variance indicate upper and lower estimates for each species, and the differences between them and other survey techniques were explicable partly by the behavioural ecology of each species or apparent changes in density. Our density estimates never exceeded the highest comparative estimates for target species or near relatives in other forest habitats, although few were available for diurnal raptors. We suggest that 1-h lookout watches over forest, where feasible, offer alternative and efficient estimates of detection, dispersion and density to conventional distance-sampling techniques conducted from within forest. They will achieve optimum accuracy when conducted during the most detectable periods for target species, particularly for obvious and sparsely dispersed bird species.

Movements, Distribution, and Abundance of Great Argus Pheasants (Argusianus argus) in a Sumatran Rainforest

ABSTRACT. We used radiotelemetry, habitat sampling, camera trapping, and line-transect surveys to explore movement patterns, distribution, and abundance of Great Argus Pheasants (Argusianus argus) in Sumatra, Indonesia. We radiotracked six adult and one subadult males. Territories averaged 14.5 ± 8.5 ha, and home-range size did not vary by month or by relative abundance of selected plant foods. Daily travel distance (849 ± 211 m) varied significantly between months but did not reflect changes in plant foods. Territories were used almost exclusively by resident males. Males preferentially used undisturbed forest (habitat I). Vegetation structure at male display sites and random points indicated that display sites were located in undisturbed forest, with few lianas and small leaf size on trees adjacent to the display site. Between 1998 and 2001, we conducted five line-transect surveys in conjunction with camera-trap surveys. Density estimates of calling males varied from 0.4 to 2.5 males km-2, and the total...

A picture is worth a thousand words: the application of camera trapping to the study of birds

AbstractThis study reviews the use of remotely triggered still cameras, known as camera traps, in bird research and suggests new methods useful for analyzing camera trap data. Camera trapping may be most appropriate for large, ground-dwelling birds, such as cracids and pheasants. Recent applications include documentation of occurrence of rare species and new species records, nest predation studies and behavioural studies including nest defence, frugivory, seed dispersal, and activity budgets. If bird postures are analyzed, it may be possible to develop behavioural time budgets. If birds are marked or individually identifiable, abundance may be estimated through capture-recapture methods typically used for mammals. We discourage use of relative abundance indices based on trapping effort because of the difficulty of standardizing surveys over time and space. Using the Great Argus Pheasant Argus argusianus, a cryptic, terrestrial, forest bird as an example, we illustrate applications of occupancy analysis to estimate proportion of occupied habitat and finite mixture models to estimate abundance when individual identification is not possible. These analyses are useful because they incorporate detection probabilities < 1 and covariates that affect the sample site or the observation process. Results are from camera trap surveys in the 3,568 km2 Bukit Barisan Selatan National Park, Indonesia. We confirmed that Great Argus Pheasants prefer primary forest below 500 m. We also find a decline in occupancy (6–8% yr−1). Point estimates of abundance peak in 2000, followed by a sharp decline. We discuss the effects of rarity, detection probability and sampling effort on accuracy and precision of estimates.

Camera trapping rare and threatened avifauna in west-central Sumatra

AbstractTropical forests are becoming increasingly degraded and fragmented by logging, which can affect the survival of forest bird species in different ways. In this study, we present avifauna data collected from a monitoring programme in west-central Sumatra that set camera traps in three study areas with different habitat types, levels of degradation and protection status. From 5,990 camera trap-nights, 248 independent bird photographs were recorded, comprising four orders and nine species, including three endemic species. The Great Argus Pheasant (Argusianus argus) was recorded in all study areas and most frequently (n = 202 photographs), followed by the threatened Salvadori's Pheasant (Lophura inornata). The greatest diversity of bird species (five) and abundance index (1.44 bird photographs/100 trap-nights) was recorded from a primary hill-submontane forest site located inside Kerinci Seblat National Park (KSNP) bordering degraded forest in a former logging concession recently repatriated into KSNP. However, inside a primary-selectively logged hill-submontane forest site spread over KSNP and an ex-logging concession, a Sumatran Ground Cuckoo (Carpococcyx viridis) was photographed. This species is noteworthy because prior to this study it had only been documented once since 1916. It is therefore crucial to use the camera trap results to increase the protection status for the ground cuckoo area. This has already happened in the other two study areas, where camera trap data have been used to reclassify the areas as Core Zones, the highest level of protection inside KSNP. This study illustrates how routine monitoring can have wider benefits through recording, and conserving, threatened and endemic non-target species in unexpected habitats that might not otherwise have been surveyed.

Effects of Vocal Behaviour on Abundance Estimates of Rainforest Galliforms

A comparative study was undertaken to assess the effects of the vocal activity of a target species on its density estimates made using line transect counts and point counts. In Kayan Mentarang National Park (Indonesian Borneo) the Great Argus Pheasant Argusianus argus displayed different levels of calling activity. The study was conducted at a period when the birds were highly vocal, and again, at the same site, when the birds were significantly less vocal. Transect counts during periods of low vocal activity resulted in 13–20% lower density estimates compared to periods of high vocal activity, but these differences were not significant. Estimates derived from five-minute point counts during periods of low vocal activity, however, were 52% lower than those from periods of high vocal activity. Comparison of the two methods shows that density estimates derived from the point count method were consistently lower than those from the line transects. The lack of a fixed calling season in Argus Pheasants makes year-round censuses possible, yet the distinct temporal differences in calling rates necessitates that caution be exercised when results obtained in different years or at different times of the year are compared. It is concluded that there is an increased need for understanding the behavioural plasticity of species if census methods are to be improved.

BIRD SPECIES AND TRAITS ASSOCIATED WITH LOGGED AND UNLOGGED FOREST IN BORNEO

The ecological consequences of logging have been and remain a focus of considerable debate. In this study, we assessed bird species composition within a logging concession in Central Kalimantan, Indonesian Borneo. Within the study area (approximately 196 km2) a total of 9747 individuals of 177 bird species were recorded. Our goal was to identify associations between species traits and environmental variables. This can help us to understand the causes of disturbance and predict whether species with given traits will persist under changing environmental conditions. Logging, slope position, and a number of habitat structure variables including canopy cover and liana abundance were significantly related to variation in bird composition. In addition to environmental variables, spatial variables also explained a significant amount of variation. However, environmental variables, particularly in relation to logging, were of greater importance in structuring variation in composition. Environmental change following logging appeared to have a pronounced effect on the feeding guild and size class structure but there was little evidence of an effect on restricted range or threatened species although certain threatened species were adversely affected. For example, species such as the terrestrial insectivore Argusianus argus and the hornbill Buceros rhinoceros, both of which are threatened, were rare or absent in recently logged forest. In contrast, undergrowth insectivores such as Orthotomus atrogularis and Trichastoma rostratum were abundant in recently logged forest and rare in unlogged forest. Logging appeared to have the strongest negative effect on hornbills, terrestrial insectivores, and canopy bark-gleaning insectivores while moderately affecting canopy foliage-gleaning insectivores and frugivores, raptors, and large species in general. In contrast, undergrowth insectivores responded positively to logging while most understory guilds showed little pronounced effect. Despite the high species richness of logged forest, logging may still have a negative impact on extant diversity by adversely affecting key ecological guilds. The sensitivity of hornbills in particular to logging disturbance may be expected to alter rainforest dynamics by seriously reducing the effective seed dispersal of associated tree species. However, logged forest represents an increasingly important habitat for most bird species and needs to be protected from further degradation. Biodiversity management within logging concessions should focus on maintaining large areas of unlogged forest and mitigating the adverse effects of logging on sensitive groups of species.

Crouching tigers, hidden prey: Sumatran tiger and prey populations in a tropical forest landscape

AbstractWe examine the abundance and distribution of Sumatran tigers (Panthera tigris sumatrae) and nine prey species in Bukit Barisan Selatan National Park on Sumatra, Indonesia. Our study is the first to demonstrate that the relative abundance of tigers and their prey, as measured by camera traps, is directly related to independently derived estimates of densities for these species. The tiger population in the park is estimated at 40–43 individuals. Results indicate that illegal hunting of prey and tigers, measured as a function of human density within 10 km of the park, is primarily responsible for observed patterns of abundance, and that habitat loss is an increasingly serious problem. Abundance of tigers, two mouse deer (Tragulus spp.), pigs (Sus scrofa) and Sambar deer (Cervus unicolor) was more than four times higher in areas with low human population density, while densities of red muntjac (Muntiacus muntjac) and pigtail macaques (Macaca nemestrina) were twice as high. Malay tapir (Tapirus indicus) and argus pheasant (Argusianus argus), species infrequently hunted, had higher indices of relative abundance in areas with high human density. Edge effects associated with park boundaries were not a significant factor in abundance of tigers or prey once human density was considered. Tigers in Bukit Barisan Selatan National Park, and probably other protected areas throughout Sumatra, are in imminent danger of extinction unless trends in hunting and deforestation are reversed.

Habitat preference of Great Argus Pheasant (Argusianus argus) in Kayan Mentarang National Park, East Kalimantan, Indonesia

Habitat preference and abundance of the Great Argus Pheasant was studied over a ten week period in the lowland forests of the Kayan Mentarang National Park, in the remote interior of Indonesian Borneo. Repeat line transect surveys, counting the number of vocalising males, were conducted in four different habitat types. Argus Pheasants were found to be most common in primary forest, and progressively less common in old and young secondary forests. Numbers of calling males were lowest in riverine forest. Argus Pheasant densities were positively correlated with a number of transect characteristics, viz. increasing tree diameter, tree height, height of the first bough and canopy cover, and with increasing remoteness. Dancing grounds were invariably located on ridges. The conservation status of the species on Borneo is briefly discussed. The Great Argus Pheasant is still widespread but thinly spread. The rapid rate of lowland forest clearance, fragmentation of once continuous habitat and increasing hunting pressure owing to increasing accessibility may become serious threats in the near future.