Justification of Red List Category
This enigmatic flightless rail is classified as Vulnerable because it has a small population, which is likely to be declining and undergoing fragmentation owing to the on-going loss of its specialised habitat. However, it is poorly known, and further surveys may reveal it to be more numerous and occur in a wider range of habitats than current information suggests.
The population is estimated to number 2,500-9,999 mature individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals.
The species is suspected to be in decline owing to the loss of its habitat through deforestation and logging of primary habitats on Halmahera, as well as the potential impacts of alien predators and hunting.
Habroptila wallacii is endemic to the island of Halmahera in North Maluku, Indonesia (BirdLife International 2001), where it is known from few specimens but an increasing number of sightings in recent years (H. Bashari in litt. 2016). These come from only a tiny handful of sites. Extensive surveys of Aketajawe-Lolobata National Park found the species present in both blocks in both 2009 and 2012, but at low density (Bashari 2012).
It is a flightless, and thus presumably strictly sedentary species, found in drier swamp areas within primary forest, often near the intersection of small rivers (Bashari 2012, H. Bashari in litt. 2016). One nest was found in 2011, in secondary dry swamp forest dominated by Pigafetta palms (Bashari and van Balen 2012). Previously the species has been reported to occur in dense, impenetrable, swampy thickets, particularly remote parts of sago swamp.
Habitat loss and fragmentation is probably the main threat, and it has possibly declined considerably given that considerable deforestation has occurred on Halmahera in recent decades (Vetter 2009). Additionally sago swamps on Halmahera have been extensively destroyed through commercial sago extraction, irrigation schemes, conversion for wet rice and, potentially, fishpond development, which may have reduced populations in this habitat. Moreover, flightless rails confined to single islands have a long history of extinction through predation by introduced species. Indeed, the species is apparently occasionally caught by dogs when local people are hunting deer and pigs.
Conservation Actions Underway
The species occurs within Aketajawe Lolobata NP which protects an area of 167,300 ha including a large area of primary forest. Extensive effort has gone in to interviewing local people about the species and its possible whereabouts, with some successes (Bashari and van Balen 2011, M. Poulsen in litt. 2007).
40 cm. Large, secretive, flightless rail. Very dark slate-grey throughout with browner wings, lower back and tail. Bright red bare parts, including eye-ring and frontal shield. Long and robust bill. Similar spp. Plain Bush-hen Amaurornis olivaceus is smaller, with shorter yellow bill and legs. Purple Swamphen Porphyrio porphyrio (recently discovered on Halmahera) is much larger and bluer, with shorter, thicker bill and conspicuous white undertail-coverts. Voice A low drumming noise is made as a contact call, there are also reports of screaming calls.
Text account compilers
Benstead, P., Bird, J., Davidson, P., Taylor, J., Tobias, J., Martin, R
Bashari, H., Mittermeier, J., Emanuelson, E., Poulsen, M.
BirdLife International (2022) Species factsheet: Habroptila wallacii. Downloaded from http://www.birdlife.org on 08/08/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 08/08/2022.