The chestnut-hooded laughingthrush (Pterorhinus treacheri) is a species of bird in the laughingthrush family Leiothrichidae endemic to Borneo. Described by the British ornithologist Richard Bowdler Sharpe as a distinct species in 1879, it was subsequently considered a subspecies of the chestnut-capped laughingthrush until 2007, when it was again raised to species status by the ornithologists Nigel Collar and Craig Robson. It is 22–24 cm (8.7–9.4 in) long, with a chestnut brown head and chin, with grey feathering on the top of the head. The upperparts and the side of the neck are slaty-grey, with a long white wing patch. The throat, breast, and upper belly are dull yellowish-brown, with purer grey flanks and a reddish-brown vent, lower belly, and thighs. It has a yellow half eye-ring behind and below the eye, while the tail has a blackish tip. Both sexes look similar, while juveniles are duller than adults.
The species inhabits montane and hill forest, forest edge, disturbed vegetation, and cultivated areas in mountains in the north-central and southeastern parts of Borneo. It is mainly found at elevations of 600–2,800 m (2,000–9,200 ft), but can be found down to 200 m (660 ft) and as high as 3,350 m (10,990 ft). It is omnivorous, feeding on arthropods, fruit, and flowers. Breeding occurs from February to April and in October, with the species building cup nests and laying clutches of two bright blue to greenish-blue eggs. It is classified as being of least concern by the International Union for Conservation of Nature due to its very large range, fairly large population, and a lack of significant population decline, but its numbers are thought to be decreasing and it is threatened by habitat destruction and habitat fragmentation.
