Argentina, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, Falkland Islands (Malvinas), French Guiana, Guyana, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, South Georgia and the South Sandwich Islands, Suriname, Trinidad and Tobago, Uruguay (B), Venezuela.
Population
Estimated population is unknown (2010).
Southern Rough-winged Swallow (Stelgidopteryx ruficollis) [XC438682]
by Mauricio \u00c1lvarez-Rebolledo (Colecci\u00f3n de Sonidos Ambientales - Instituto Humboldt) from Cristalino Jungle Lodge, Alta Floresta, Mato Grosso, Brazil (call)
Southern Rough-winged Swallow (Stelgidopteryx ruficollis) [XC443392]
by JAYRSON ARAUJO DE OLIVEIRA from Santa Rita do Novo Destino, Goi\u00e1s, Ch\u00e1cara Jayrson, Brazil (flight call)
Subspecies
Formerly considered conspecific with Northern Rough-winged Swallow (Stelgidopteryx serripennis), and subspecies decolor has been regarded as intermediate between the two species, but they are separated altitudinally where ranges overlap in Costa Rica. Sometimes treated as monotypic, as subspecies intergrade, also depth of plumage colour varies clinally, becoming generally darker from north to southern and east. Birds from Surinam named as subspecies cacabata, but description believed to have been based on migrants of nominate subspecies.
The following 4 subspecies are recognised:
decolor Griscom, 1929 - Western Costa Rica and western Panama.
uropygialis (Lawrence, 1863) - Caribbean lowlands southern from eastern Honduras, Pacific lowlands of eastern Panama, western Colombia, Ecuador and north-western Peru.
aequalis Bangs, 1901 - Northern Colombia, western Venezuela and Trinidad.
ruficollis (Vieillot, 1817) - South-eastern Colombia, eastern Venezuela, the Guianas and Brazil south to eastern Peru, Bolivia, northern and north-eastern Argentina (south to Salta, Formosa, Entre Ríos and northern Buenos Aires) and Uruguay.