Chestnut-necklaced partridge

This species was described by Thomas Campbell Eyton as Perdix Charltonii in 1845.[2] The IOC World Bird List recognises the subspecies T. c. charltonii found in the Malay Peninsula, T. c. atjenensis in Sumatra, and T. c. graydoni in Borneo.[3] The Handbook of the Birds of the World considers graydoni to be a separate species. Some authorities have considered the green-legged partridge (A. chloropus) to be conspecific with this species.[4]

The chestnut-necklaced partridge is 26–32 cm (10–13 in) long. The male weighs about 290 g (10 oz) and the female weighs about 250 g (8.8 oz). The crown and nape are brown, with dark speckles. The whitish supercilium, throat and neck have brown streaks. The upper breast is chestnut, with a blackish collar above it. The lower breast is brown, and the belly and flanks are buff. There are dark scales on the lower breast and flanks.[5] The upperparts are brown, finely marked blackish and buff. The beak is greenish yellow, and the legs are yellow.[6] The female bird is smaller and a little duller than the male. The subspecies atjenensis has brighter plumage, and graydoni has greenish-yellow legs.[5]

This partridge is found in the Thai-Malay Peninsula, Aceh, South Sumatra and Sabah.[5][1] Its habitat is lowland evergreen forest and secondary forest.[5]

This partridge probably forages in small groups, eating seeds, berries and termites. Its breeding has not been recorded.[5] Its call is loud, steady couplets and triplets of whistles, and pairs often duet.[6]

The number of mature individuals is probably less than 10,000 and may be less than 2500. On Sumatra, the species has rarely been recorded recently. It is suspected to be declining because deforestation, logging and forest fires have destroyed much habitat and it is trapped and traded. The IUCN has assessed it as a vulnerable species.[1] The IUCN considers T. c. graydoni a separate species and has assessed it to be of least concern.[7]