Vagrant to Falkland Islands (Malvinas), South Georgia and the South Sandwich Islands.
Chile (south of Atacama) and adjacent western Argentina (Neuquén to Santa Cruz) south to Tierra del Fuego; Juan Fernández Is. southern populations winter northern into east-central Argentina.
 
Population
Estimated population is unknown (2010).
Green-backed Firecrown (Sephanoides sephaniodes) [XC384664]
by Cristian Pinto from Plaza Panama, Vitacura, Santiago, Regi\u00f3n Metropolitana, Chile (call)
Green-backed Firecrown (Sephanoides sephaniodes) [XC13253]
by Daniel Gonz\u00e1lez Amat from Santiago, \u00d1u\u00f1oa, Chile (call, flight call)
Subspecies
Genus seems to be closely related to a high-Andean lineage that includes Lesbia, Metallura, Oreonympha and Oreotrochilus. Sister-species relationship with Juan Fernandez Firecrown (Sephanoides fernandensis) supported by recent DNA studies. Present generic name based on misspelling of species name; some recent authors have erroneously transferred spelling of generic name to species name, thus referring to "Sephanoides sephanoides". In past, alternatively listed as Sephanoides galeritus, although the historical justification for this is doubtful since that name cannot be identified as present species.