Justification This species has an extremely small, declining and severely fragmented population as a result of deforestation, drainage of wetlands, hunting, disturbance and potentially a number of unknown factors. It therefore qualifies as Critically Endangered, based on a projected extremely rapid population decline over the next three generations (25 years). If conservation efforts succeed in bringing the largest remaining populations, in north-eastern Cambodia and along the Mekong channel, under effective protection, the species may warrant downlisting.

Family/Sub-family Threskiornithidae

Species name author (Hume, 1875)

Taxonomic source(s) Sibley and Monroe (1990, 1993)

Identification 75-85 cm. Large, dark ibis with distinctive pale collar, bluish-tinged at close range. Dark overall, blackish, naked head, dull red legs and whitish patch on inner forewing. Similar species Red-naped Ibis Thaumatibis papillosa has red patch on hind crown and nape and lacks white collar. Giant Ibis Thaumatibis gigantea is much larger with uniformly paler, dark-barred head, upper neck, wing-coverts and secondaries. Voice Territorial birds utter loud, hoarse screaming errrrrrh or errrrrroh and moaning errh errh errh errh. Also screams mixed with honking errrrh owk owk owk owk and more subdued ohhaaa ohhaaa and errrr-ah. Hints Search permanent wetlands in the Mekong lowlands during the dry season or remote forested rivers in Kalimantan.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

50-249

decreasing

88,900 km²

No

Range & population Pseudibis davisoni now occurs in northern and eastern Cambodia, extreme southern Laos and East Kalimantan, Indonesia. It was previously widely but patchily distributed across much of Thailand, Laos, south and central Vietnam and Cambodia, parts of Myanmar, Kalimantan (Indonesia), Sarawak (Malaysia) and south-west Yunnan, China, but has declined dramatically during the 20th century. It is extinct in Thailand and there are no recent records from Myanmar; and it has been described as the most threatened large waterbird in South-East Asia based on the widespread declines observed⁵. It is almost certainly extinct as a breeding species in Vietnam and now only occurs as a rare non-breeding visitor. In Cambodia significant populations are known from Siem Pang District (c.100 individuals) and along the Mekong river channel between Kratie and the Laos border (c.75-125 individuals) ⁷. Tmatboey, in the Northern Plains, Cambodia, supports the largest protected breeding population with 15-20 birds at the end of the 2007 breeding season. Additional groups (1-10 birds each) have been recorded elsewhere, particularly from the south-eastern shore of the Tonle Sap lake, Srepok river and the O Te lowlands. The species was recently recorded at Lomphat Wildlife Sanctuary in Ratanakiri¹¹, and in Mondulkiri Province, the latter representing a southern extension of its current known range in the country⁶, and it might be found further south still in Kompong Cham province along the Mekong^7,8. Early dry season counts at Siem Pang have increased in recent years, from 23 in January 2003 and 33 in November 2004 to 70 in November 2005 and 108 in November 2006⁹. The reasons behind this apparent increase are unknown: it may result from improved survey effort or a greater abundance of feeding locations as a consequence of human habitat modification^7,8. In Kalimantan, the population at the main locality along the Mahakam River was estimated at 30-100 individuals, but recent studies reveal a decline following extensive El Niño Southern Oscillation (ENSO)-derived forest fires².

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: Wetlands and grassland, such as pools, marshes, open grasslands or watercourses including wide rivers with sand and gravel bars were formerly important for the species, however at least in Indochina deciduous dipterocarp forest (which is usually inundated during the wet season) now appears to be of major importance¹¹. Trapaengs (seasonal pools) are particularly favoured during the dry season, with a shift to matrix sites such as fallow rice fields and the dipterocarp forest itself after rainfall events¹². The species has been recorded along large rivers such as the Mekong in Cambodia and on the Mahakam in Kalimantan. It is also been recorded from the mosaic of shrub and grasslands on the Tonle Sap floodplain. In Cambodia it has been recorded nesting during the dry season (December to April) on the edges of seasonally abandoned wet season rice paddy and in the Mekong channel. It has been observed feeding in soft substrates on the forest floor as well as at small waterbodies³; also in sediment formations in river channels. In South-East Asia the species may be associated with large ungulates which may help to create and maintain seasonal pools within the dry forest landscape⁴, and its preference for trapaengs with bare substrate and low vegetation supports this theory¹². Large wild ungulates have now all but disappeared from the region, and the species may now be more closely associated with domestic livestock¹¹. Available evidence gives no suggestion that the species undertakes major seasonal movements. White-shouldered Ibis aggregate into large flocks (max. count of 80 individuals in Siem Pang District, Cambodia).

Threats It has declined as a result of habitat loss, through logging, widespread piecemeal clearance of lowland forest, conversion of wetlands for agriculture (most of the Mekong floodplain in southern Laos has been converted to rice-paddy) and agro-industrial and infrastructure development (such as the proposed dams on the River Srepok¹¹). Habitat loss has been compounded by hunting of adult birds, eggs and chicks for food and disturbance, leading to the loss of secure feeding, roosting and nesting areas⁸. The hunting pressure is exacerbated by the fact that their primary habitats appear to be also a focus of people: large rivers and grassland/field complexes with high densities of ungulates and domestic livestock, however hunting may now be less of a threat in Cambodia following education initiatives and the confiscation of weapons¹¹. Recent evidence suggests that forest fires in Borneo resulting from an El Niño Southern Oscillation (ENSO) event shifted the distribution of this species to unburnt stretches of rivers². There is considerable evidence that the species is associated with large ungulates in South-East Asia which create and maintain the short-sward grassland feeding areas that the ibises depend upon within the dry forest landscape⁴. Hence, the demise of wild ungulates within the region may have catalysed its rapid decline resulting in no remote refugia for the species^7,8. Moreover, its dependency on herbivore-altered habitats means that remnant areas are close to people and associated with domestic livestock, making it more vulnerable to human induced habitat modification^7,8. Probably the most significant threats currently come from land concessions for logging or plantations, and infrastructure development such as dam construction, which threaten even those areas that currently have protected status¹¹.

Conservation measures underway It occurs in several protected areas including Kulen Promtep Wildlife Sanctuary (documented breeding population), Preah Vihear Protected Forest, Mekong Ramsar site, Ang Trapeang Thmor, Seima Biodiversity Conservation Area, Srepok Wilderness Area (part of the Mondulkiri Protected Forest), Integrated Farming and Biodiversity Areas, Cambodia, and Xe Pian National Protected Area (NPA), Laos. It is depicted on public awareness material distributed in Laos and Cambodia. The species is considered to be the most threatened large waterbird in South-East Asia and was a priority species during the designation of Cambodian IBAs and priority areas for conservation in the 'dry forest ecoregion' of South-East Asia⁵. Research has been conducted into the species's foraging ecology and nesting in Kulen Promtep Wildlife Sanctuary, Cambodia, and is planned for other areas. A nest protection scheme with incentives to local people for protecting nest-sites along the Mekong and in Siem Pang¹ is being established. A PhD studying the species's foraging ecology began in 2008. A community-managed ecotourism initiative has been established at Tmatboey. As part of BirdLife's Preventing Extinctions programme Species Guardian Kry Masphal has begun to implement the following actions: 1. A proposal to establish a Protected Forest in Western Siem Pang has been prepared, reviewed, revised and approved by the Provincial Governor. 2. The government have been lobbied to complete the notification process, including through producing a poster about the international importance of Western Siem Pang for conservation and distributing this to all relevant governmental and non-governmental stakeholders. Large information boards were placed in five key villages within the IBA to inform local people about development plans and threats to their land from proposed concessions. The Deputy Governor of Stung Treng issued a letter in support of the proposal to designate Western Siem Pang a Protected Forest. 3. Research and monitoring continues to be carried out, focusing on the foraging ecology of the species and examining the influence of traditional land management practices. 4. A Local Conservation Group at Western Siem Pang has been supported since August 2007, and conducts monthly patrols to the most important trapaengs to record key species and any illegal activities. In September-November 2007, 40 chainsaws were confiscated and one illegal logger was sent to court as a result of information provided by the patrol team.

Conservation measures proposed Finalise the establishment of a Protected Forest in Western Siem Pang¹. Continue monitoring the known populations in Siem Pang, Northern Plains and Mekong channel and in other parts of its range as well as researching the ecological requirements of the species¹. Conduct further surveys in Borneo, central, northern and eastern Cambodia and the Satay area of Vietnam to quantify remaining populations, only in areas where conservation intervention is considered reasonable and there are grounds for considering a significant population might be found. Establish further protected areas or integrated conservation development projects covering landscape-level habitat tracts supporting populations, particularly in northern Cambodia and along the Mahakam river, East Kalimantan. Enforce strict protection at important sites. Promote widespread conservation awareness programmes aimed at reducing wetland disturbance and large waterbird exploitation in Indochina.

References Birdlife International (2001). 1. Anon (2007). 2. Sözer and Nijman (2005). 3. T. Clements pers. comm. (2006). 4. T. Evans pers. comm. (2006). 5. Tordoff et al. (2005). 6. Bird et al. (2007). 7. R. Timmins in litt. (2007). 8. T. Clements in litt. (2007). 9. BirdLife International in Indochina (unpublished data). 10. J. Eames in litt. (2008). 11. H. Wright in litt. (2008). 12. Wright (2008).

Further web sources of information

Fully detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001), together with new information collated since the publication of the Red Data Book

Species Guardian Action Update November 2008

Text account compilers Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Geoffrey Davidson (Malaysian Nature Society), Pete Davidson (BirdLife International), Nic Peet (BirdLife International), John Pilgrim (BirdLife International), Andy Symes (BirdLife International), Joe Tobias (BirdLife International)

Contributors Tom Clements (Wildlife Conservation Society), Jonathan C Eames (BirdLife International in Indochina), Tom Evans (Wildlife Conservation Society), Rob Timmins, Hugh Wright (University of East Anglia)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Andy Symes (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Pseudibis davisoni. Downloaded from http://www.birdlife.org on 10/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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