The crescentchests (genus Melanopareia) are a distinctive group of small suboscine passerine birds native to South America, particularly arid scrub habitats. These birds are notable for a prominent, crescent-shaped band across their chest, which gives rise to their common name. Crescentchests are usually between 14-16 cm long and weigh 16-23 g with long tails, and they mainly forage on the ground, although little is known about their diet. The family, Melanopareiidae, was established to classify these birds after they were removed from the tapaculos family, Rhinocryptidae, in 2007. The crescentchests encompass five species with varying distributions across Brazil, Bolivia, Paraguay, Argentina, Ecuador, and Peru. The olive-crowned crescentchest's breeding behaviors have been observed—seasonal breeding, constructing a 15 cm high nest from vegetable fibers and palm fronds close to the ground, with a clutch of two to three white eggs blotched with black spots. Currently, none of the crescentchest species are considered threatened except for the Marañón crescentchest, which is listed as near threatened due to its small and uncommon range despite being tolerant of some environmental disturbance.