About Melanopareia maximiliani (Orbigny, 1835)
The olive-crowned crescentchest (Melanopareia maximiliani) is 15 cm (5.9 in) long. Males weigh 17.1 to 18.0 g (0.60 to 0.63 oz), one recorded female weighed 16.7 g (0.59 oz), and unsexed specimens weigh 16.9 to 18.2 g (0.60 to 0.64 oz). The nominate subspecies has olive-brown crown and upperparts, deep buff colored throat, and ochraceous chest and belly. It features a narrow buff supercilium with a black mask below it, and a black crescent and a chestnut band between the throat and chest. The subspecies M. m. argentina is similar to the nominate but has paler underparts. The subspecies M. m. pallida is even paler than M. m. argentina, its throat is more cinnamon than buff, and its facial mask is a lighter shade of black. For distribution, the nominate subspecies occurs in La Paz Department of western Bolivia. M. m. argentina ranges from central Bolivia to northwestern Argentina. M. m. pallida is found in southeastern Bolivia, western Paraguay, and northern Argentina. As for habitat, the species generally lives in dry scrub and grassy areas with small bushes. M. m. pallida also regularly occurs in sawgrass in the Chaco Basin. Most of the species' range sits at an elevation between 1,700 and 2,950 m (5,580 to 9,680 ft), though it can be found as low as 1,200 m (3,900 ft) in Argentina.
