The white-necked thrush (Turdus albicollis) is a songbird found in forest and woodland in South America. The taxonomy is potentially confusing, and it sometimes includes the members of the T. assimilis group as subspecies, in which case the "combined species" is referred to as the white-throated thrush (a name limited to T. assimilis when the two are split). On the contrary, it may be split into two species, the rufous-flanked thrush (T. albicollis) and the grey-flanked thrush (T. phaeopygos). Description This thrush is long and weighs . The upperparts are dark brown, turning duskier or greyer towards the ocular region. The throat is white with dense dark streaks, except on the lowermost part, resulting in the appearance of a white crescent below the dark-streaked white throat. This has given rise to both its English and scientific name. The crissum (the undertail coverts surrounding the cloaca) and central belly are whitish, and the chest is grey often tinged brown. The members of the nominate group have conspicuous rufous flanks, and the bill is yellow with a dusky culmen. The flanks are paler and more tawny in the subspecies crotopezus, which also has the entire upper mandible dusky. The members of the phaeopygos group lack contrasting rufous or tawny flanks, and have bills that are almost entirely dusky. All subspecies have pinkish-brown legs and a reddish or yellow eye-ring. Sexes are similar, but juveniles are duller, with dull orange spotting above, and brownish spotting below. The song is a relatively musical, often rather monotonous . The calls is a distinctive , while the alarm is a rough . Distribution and habitat The nominate group (including subspecies paraguayensis and crotopezus) occurs in eastern Brazil, far northern Uruguay, eastern Paraguay and far north-eastern Argentina. The phaeopygos group (including subspecies phaopygoides, spodiolaemus and contemptus) is mainly found in the Amazon Basin, but with populations extending along the eastern slope of the Andes as far south as north-eastern Argentina, and as far north as western Venezuela, with extensions along the Coastal Range, the region centered around Serranía del Perijá and Sierra Nevada de Santa Marta, and the islands of Trinidad and Tobago. Both groups are mainly associated with humid forest and woodland. In the case of the nominate group, mainly the Atlantic Forest, and in the case of the phaeopygos group, mainly the Amazon Rainforest or humid forests and woodlands near mountains. It rarely ventures far