Data Zone
Justification of Red List category
This species has a small range in which ongoing forest loss and degradation are causing a reduction in the area of occupied habitat, and has a small, declining population. However, the species occupies multiple islands and parts of the range do not appear to be impacted by any threat, reducing the potential risk of extinction. The population is arranged in multiple subpopulations, the largest of which exceeds 1,000 mature individuals. As such, it only partially meets the thresholds for listing as threatened, and is assessed as Near Threatened.
Population justification
The total area of the potentially occupied range of the species is 2,951 km2. The species is regularly detected by voice at rates similar to another closely related member of the genus occurring in equivalent habitat, M. reinwardt, which has been estimated to occur at densities of 5.6 inds/km2 in similar habitat (Marsden et al. 1998). If M. geelvinkianus occurs in 30% of the available area, and occurs at similar densities to M. reinwardt, the population is very provisionally estimated at 4,950 individuals, which is placed in the band 2,500-9,999 mature individuals, noting that the density estimate is derived from calling birds that are likely to be mature.
The species occupies several separate islands. Birds on satellite islands around Biak-Supiori and those around Numfor are more likely to be connected, but regular dispersal between Biak, Numfor and Mios Num appears unlikely, hence the most plausible number of subpopulations is three. The largest of these is Biak-Supiori, on which thee extent of habitat remaining on Biak-Supiori, especially to the north, indicates that more than half of the population would be expected to be present in this subpopulation and exceeds 1,000 mature individuals. In southern Biak the population is reported to have noticeably declined due to a recent increase in the human population and associated increase in hunting for food (M. Halaouate in litt. 2021). On the tiny island of Mios Korwar/Pulau Bepondi landslips caused a sudden dramatic loss of forest area in 2018 (Global Forest Watch 2021), likely to have considerably reduced the population present. Consequently the species is inferred to be suffering a continuing decline in population size, at a suspected rate of between 5-15% over the past and future three generations.
Trend justification
The species is inferred to be declining at a slow to moderate rate, owing to on-going habitat loss and degradation, coupled with localised hunting pressure (Global Forest Watch 2021, M. Halaoute in litt. 2021). Across the range 4.6% of forest cover has been lost over the past three generations (data from Global Forest Watch 2021). While the species has been noted in disturbed habitats, it is believed to have at least a medium-high level of forest dependency, such that the area of forest cover is suspected to be directly related to the number of individuals that can be supported, and hence the rate of forest cover loss is suspected to approximate a rate of population reduction. In addition, the species is hunted, at least on Biak island, and a noticeable decline in the population there has coincided with a rapid increase in the human population (M. Halaouate in litt. 2021). Hunting is therefore considered likely to be having an additional population impact, such that the suspected rate of population reduction is placed within a band of 5-15% over three generations.
Megapodius geelvinkianus is endemic to Biak-Supiori in Papua (formerly Irian Jaya), Indonesia, and its satellite islands, Mios Korwar, Numfor, Manim and Mios Num (Mayr 1941). It is not clear whether one specimen, apparently from Manokwari on mainland Papua, represents a straggler from a nearby island or a mislabelled specimen (Jones et al. 1995). It was formerly common on Biak (Mayr and Meyer de Schauensee 1939) and it was heard regularly during the course of field visits to Biak between 1983 and 1997 (K. D. Bishop in litt. 2007). It was recorded daily in and around Biak-Utara Reserve in 1997 (S. van Balen and B. M. Beehler in litt. 2000), and is still seen regularly by visitors (S. van Balen in litt. 2012, eBird 2021), but the population on Biak is thought to have declined, attributed to hunting associated with a recent rapid increase in the human population (M. Halaouate in litt. 2021). There are also numerous recent records on Numfor and recent records on Mios Korwar (eBird 2021), though the current status on Mios Num is uncertain. Only "small numbers" were seen during the 1990s on Owi (a satellite of Biak) and Supiori (Jones et al. 1995), though the latter is thought to be where the biggest population remains (M. Halaouate in litt. 2021). On the very small (c. 3km2) island of Mios Korwar almost one-third of all forest was lost in 2018 (Global Forest Watch 2021), demonstrating the potential for sudden range contraction to affect the species. Overall, the population is inferred to be declining owing primarily to unquantified impacts of hunting in accessible parts of the range and a persistent though relatively slow rate of forest loss.
It is apparently shy and wary but has been recorded in primary forest, logged forest, secondary growth, dry scrub and scrub near a river. It is regularly seen in disturbed habitat (S. van Balen in litt. 2012), but is considered to have at least a medium level of forest dependency. However, there is no information on its habitat preferences, general habits, diet or breeding biology, although these are probably broadly similar to other Megapodius species. It presumably builds nest-mounds or buries its eggs between decaying roots of trees (Jones et al. 1995).
Specific threats are undocumented, but are suspected to include egg-collecting, although its widely spaced nest-mounds may reduce this risk (S. van Balen and B. M. Beehler in litt. 2000), hunting (M. Halaouate in litt. 2021) and perhaps predation by introduced mammals (Dekker and McGowan 1995). Much forest on Biak (particularly the southern plains) has been destroyed or damaged by logging and subsistence farming; much of the remainder is under pressure (Bishop 1982, K. D. Bishop in litt. 1996, D. Holmes in litt. 2000) although the north part of the island appears to be secure (S. van Balen in litt. 2012). Most of Supiori comprises virtually impenetrable forested limestone mountains, which is likely to be safe from habitat degradation. Much forest also remains on Numfor and Mios Num, such that there appears to be a sizeable proportion of the population that is currently minimally impacted or unaffected by the described threats. Within the range of the species between 2001 and 2019, 15.3kha of tree cover was lost, equivalent to a 5.3% decrease in tree cover since 2000 (Global Forest Watch 2021), or a 4.6% decrease in the past three generations. This or a similar rate of forest loss is expected to continue, but the location of particular deforestation events can have disproportionate effects: in 2018 alone 20% of the forest area on Mios Korwar/Pulau Bepondi was lost (Global Forest Watch 2021), potentially through landslips, which is suspected to have considerably reduced the species's population on this tiny island and increased the risk of extinction there, which would considerably reduce the species's Extent of Occurrence.
The human population on Biak has increased rapidly in recent years (M. Halaouate in litt. 2021), with associated increases in construction on the island but also records of snares set to capture terrestrial vertebrates in forest (M. Halaouate in litt. 2021), suggesting an increase in hunting pressure as well.
Climate change is suspected to affect most megapodes in the future, with all species predicted to be exposed to a two degrees Celsius increase in mean temperature within their range by 2070 (Radley et al. 2018). However, the population impact of this is unclear, and the species was assessed as 11th out of 21 species assessed for vulnerability to climate change, with the relatively small range already noted accounting for almost all of the points scored in this assessment: it was considered only at moderate risk from changes in rainfall and through barriers to dispersal and low for habitat specialism (Radley et al. 2018).
Conservation Actions Underway
There are two protected areas on the islands, Biak-Utara and Pulau Supiori Nature Reserves, which cover substantial areas of lowland and hill forest on Biak and Supiori (Sujatnika et al. 1995, Protected Planet 2021a,b).
36 cm. Medium-sized, all-brown megapode. Plumage largely dark grey with slight crest. Reddish or bluish face. Red or dark grey legs. Similar spp. No other gamebirds occur on these islands. Differs from rails such as Rufous-tailed Bush-hen Amaurornis moluccanus by crest, short bill and leg colour. Voice Various crowing and clucking calls. Hints Commonly heard and seen in Biak Utara Reserve.
Text account compilers
Martin, R.
Contributors
Beehler, B.M., Bishop, K.D., Dekker, R., Dutson, G., Holmes, D., van Balen, S., Davis, R.A. & Halaouate, M.
Recommended citation
BirdLife International (2024) Species factsheet: Biak Scrubfowl Megapodius geelvinkianus. Downloaded from
https://datazone.birdlife.org/species/factsheet/biak-scrubfowl-megapodius-geelvinkianus on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.