The Saffron-billed Sparrow is the southernmost representative of the genus Arremon, it ranging over the interior of south-central Brazil and eastern Bolivia south to northern Argentina, where it is a locally common but unobtrusive resident in the undergrowth of deciduous woodland, both in arid and humid regions. Its plumage recalls that of other congenerics. Males have the head black, with a white post-ocular supercilium and throat, the latter with a black lower border. The rest of the underparts are whitish with grayish flanks, and the upperparts are mainly olive-green or grayish, depending on subspecies (of which four are recognized). The bill is mostly orange-yellow.