Argentina, Belize, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Guatemala, Guyana, Honduras, Mexico, Nicaragua, Panama, Peru, Suriname, Trinidad and Tobago, USA (B), Venezuela.
Population
Estimated population is 20,000,000 (2010).
Dusky-capped Flycatcher (Myiarchus tuberculifer) [XC250065]
by Niels Krabbe from Azuay: se-slope Cerro Quillotu\u00f1i, Ecuador (call, calls)
Dusky-capped Flycatcher (Myiarchus tuberculifer) [XC250291]
by John V. Moore from Loja: Celica mts.: w-slope between Celica and Guachanam\u00e1, Ecuador (call, trilled call)
Subspecies
Taxonomy highly complex and almost certainly more than one species involved. Phylogenetic analysis of mitochondrial DNA indicates that those Mexican and Panamanian populations examined are more closely related to Sad Flycatcher (Myiarchus barbirostris) of Caribbean than to most South American populations of present species. Populations of nominate subspecies from Argentina, lowland Ecuador and Guyana formed a well-supported clade. Taxonomic status of atriceps particularly doubtful: birds from northern extremity of range (Ecuador) found to be closely related to Mexican and Panamanian populations of platyrhynchus (sensu lato) and nigricapillus, whereas those from southern extremity (Argentina) were closer to nominate (these findings may be due to introgression, hybridization, faulty taxonomy, or a combination of these factors). Further, minor but constant morphological differences in plumage and size exist between northern (Ecuador, Peru, northern Bolivia) and southern populations. Subspecies intergrade widely throughout most of species' range, and differences among many of them are at present described in unconvincing and unsatisfactory terms of degrees of shading on dorsal surface. Further study is required.
The following 13 subspecies are recognised:
olivascens Ridgway, 1884 - Breeds south-western USA (central and south-eastern Arizona, south-western New Mexico) and north-western Mexico (north-western Chihuahua southern in mountains to eastern Sinaloa, western Durango and northern Nayarit). Winters western and southern Mexico (southern Sonora south to Santa Efigenia, in Oaxaca).
querulus Nelson, 1904 - South-western Mexico from southern Sinaloa south, including Tres Marías Is, to Oaxaca.
lawrenceii (Giraud Jr, 1841) - Eastern Mexico (Nuevo Léon south to Tabasco and Chiapas) south to highlands of Guatemala and El Salvador.
manens Parkes, 1982 - Eastern Mexico (eastern Tabasco east to Yucatán and Quintana Roo) and northern Belize.
platyrhynchus Ridgway, 1885 - Cozumel I, off north-eastern Yucatán Peninsula.
connectens Miller, W & Griscom, 1925 - Western Belize and Guatemala south to northern and central Nicaragua.
littoralis Zimmer, JT, 1953 - Pacific coast of Nicaragua and north-western Costa Rica.
nigricapillus Cabanis, 1861 - Extreme south-eastern Nicaragua, Costa Rica (except extreme north-west) and western Panama.
brunneiceps Lawrence, 1861 - Eastern Panama (eastern from Canal Zone) and western Colombia (south through Cauca and Magdalena Valleys to Valle and Huila).
pallidus Zimmer, JT & Phelps, 1946 - North-eastern Colombia and northern and western Venezuela.
tuberculifer (D'Orbigny & Lafresnaye, 1837) - Lowland Amazonia (except much of south-east), also Trinidad, and south-eastern Brazil.
nigriceps Sclater, PL, 1860 - South-western Colombia (upper Cauca Valley) south to western Ecuador (south to Guayas and Chimborazo).
atriceps Cabanis, 1883 - Southern Ecuador southern in Andes to Argentina (south to Tucumán).
BirdLife International Species Factsheet