- Order: Passeriformes
- Family: Thamnophilidae
Buenaventura, El Oro, Ecuador; 2 February 2012 © Andrew Spencer
Confined to the Pacific slope of northwestern South America, from Colombia to western Ecuador, this uncommon to locally fairly common antbird typically inhabits dark, shady ravines within wet lowland forest below 1500 m, where lone birds or pairs keep low above the ground, searching for arthropods. Males are predominantly dark gray, becoming blacker over the wing coverts, which are tipped white, and have red irides; this latter feature is shared by females, which in contrast have a stippled throat pattern, largely brown upperparts, and an ochre-brown ventral region. Most easily located by voice, the Esmeraldas Antbird is generally secretive and, in consequence, a relatively poorly known species, with few natural history observations having been published. The Esmeraldas Antbird forms a superspecies with the Dull-mantled Antbird (Myrmeciza laemosticta).
. 2010. Esmeraldas Antbird (Myrmeciza nigricauda), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=394771