Range map of double-collared crescentchest (Melanopareia bitorquata)
Adapted from : 

Collared Crescentchest. Jacob Drucker, Birds of the World. The Cornell Lab of Ornithology, https://birdsoftheworld.org
Lopes, L.E.; Gonzaga, L.P. (2016). « Melanopareia bitorquata (d'Orbigny &amp; Lafresnaye, 1837) is a distinct species: an appraisal of morphological variation in the Collared Crescentchest Melanopareia torquata (zu Wied-Neuwied, 1831) (Aves: Melanopareiidae) ». Zootaxa. 4193(1): 138-150. ISSN 1175-5326. doi:10.11646/zootaxa.4193.1.6.
Cephas