ត្រយងយក្ស ; ឳលើក
Identification: 102–106 cm; c. 3515 g (one male). Unmistakable due to large size. Upperwing-coverts mainly silvery grey, contrasting with a darker body and flight feathers. Narrow black stripes across nape. Pseudibis davisoni is smaller and uniformly darker with whitish collar and white patch on inner wing-coverts. The juvenile has short grey feathers on hindcrown and hindneck, lacking dark bands on these plumage tracts; also has shorter bill and brown or blackish eyes (dark red in adults).
Habitat: Lowlands, occurring in lakes, swamps, seasonally flooded marshes, paddy fields (although recent study in Cambodia found no evidence of species using such habitats), wooded plains with patches of grassland (veals, many of which originate from historic rice cultivation, but the sward is typically taller than at recently abandoned paddies), humid clearings and pools (trapaengs) in deep semi-evergreen and dry dipterocarp forest,
Food and Feeding: Until recently, almost nothing known, but now subject to several studies in Cambodia. Stomach contents of one bird contained many crabs, but was also thought to consume locusts, cicadas and seeds; however, initial study in Cambodia revealed that frogs (50% of all identified prey items) were particularly important (perhaps only later in dry season), followed by insects, mole-crickets and larvae, with eels constituting 3·5% of prey captured, while crabs and fish also form part of diet..
Breeding: Nests in the wet season, commencing late Jun in Cambodia. Clutch usually, perhaps always, two eggs, probably laid at 1·5-day intervals, incubated 32 ± 1·16 days, with fledging taking 70 ± 4·64 days.
Population: Global population estimated at 115 pairs, and about 345 birds in 2012. Some areas of high density in N Cambodia, including Preah Vihear Protected Forest and Kulen Promtep Wildlife Sanctuary (with 30–40 nests monitored annually) and Western Siem Pang Important Bird Area (possibly 40 pairs), with relatively low-density populations in Lomphat Wildlife Sanctuary, Seima Protection Forest, Mondulkiri Protected Forest and Phnom Prich Wildlife Sanctuary, and additional recent records from Veunsai proposed Protected Forest in Ratanakiri province.