Crescentchests (Melanopareia) are small, slender terrestrial songbirds. All species of crescentchest have long tails, relatively long legs, and are boldly patterned. Collared Crescentchest has a long, narrow white supercilium, extensive black on the side of the head, a buffy throat and a distinctive rufous nuchal collar. The upperparts of Collared Crescentchest are rufescent brown, with a semiconcealed white dorsal patch. The underparts are tawny buff, except for a black pectoral band.
Collared Crescentchest is the only species of crescentchest in its range, so is unlikely to be confused with any other species. Olive-crowned Crescentchest (M. maximiliani) has more olive upperparts, richer ochre underparts, and lacks the rufous nuchal collar. Olive-backed Crescentchest occurs on the east slope of the Andes in Bolivia and Argentina, and in the chaco.
The following description is based on Krabbe and Schulenberg (2003), and refers to nominate torquata; see also Geographic Variation:
Adult: Crown and nape gray brown. The crown is bordered laterally by a narrow white supercilium, narrowly edged with black, that begins just above the base of the bill and continues to the nape. Lores and side of head black. Upper back and sides of the neck rufous, forming a collar. Back and rump brown, with a concealed white patch in the center of the back. Remiges and rectrices rufescent brown; upper wing coverts narrowly edged with pale olive or white. Throat buff. Black crescent across breast, with a very narrow white border across upper edge. Underparts buff; sides of breast pale olive brown, flanks deeper buff washed with olive.
Information needed. Contribute
Bill: maxilla black; mandible silver or blue gray, tip black.
Tarsus and toes: pale flesh.
Bare parts color data are from Krabbe and Schulenberg (2003).
Total length: 14.5 cm (Krabbe and Schulenberg 2003, Ridgely and Tudor 2009).
Linear measurements (Drucker, personal observations):
male (n = 3): wing length, 48.64- 52.86 mm; tail length, 61.52- 64.81 mm; culmen, 12.8-16.82 mm; tarsus, 16.62- 22.09 mm.
female (n = 1): wing length, 52.8 mm; tail length, 65.16 mm; culmen, 13.04 mm; tarsus, 19.83 mm.
Mass: bitorquata, male mean 18.0 g (range 16-23 g, n = 8; N.K. Krabbe and T.S. Schulenberg, unpublished), 6 female mean 18.4 g (range 17-20 g, n = 6; N.K. Krabbe and T.S. Schulenberg, unpublished); rufescens, 16.5, 18.0 g (n = 2, unsexed; Marini et al. 1997).