Description wikipedia

The green-backed firecrown (Sephanoides sephaniodes) is a hummingbird in the "coquettes", tribe Lesbiini of subfamily Lesbiinae. It is found in Argentina, mainland Chile, and the Juan Fernández Islands. The green-backed firecrown is 10 to 10.5 cm (3.9 to 4.1 in) long. Males weigh about 5.5 g (0.19 oz) and females about 5 g (0.18 oz). The species is sexually dimorphic, with larger, short-billed males, and smaller, longer-billed females. Adults of both sexes have bronzy green upperparts, slaty green wings and tails, and pale buff underparts with black and green spots. Adult males have the eponymous iridescent red-yellow crown. Juveniles of both sexes have rusty feather edges on the head and their underparts have a cinnamon tone. Because the young are sexually monochromatic, it is difficult to assign a sex to them. The green-backed firecrown is found in Chile from south of the Atacama Region all the way to the southern tip of South America, in the adjoining areas of southern Argentina, and east across central Argentina to the Atlantic coast. (See Behavior:Movement below for details.) An isolated population is found on Robinson Crusoe and Alejandro Selkirk Islands of the Juan Fernández group, some 770 km (420 nmi) off the Chilean coast. It has been recorded as a vagrant on the Falkland Islands. The species inhabits forest edges, plantations of introduced Eucalyptus, clearings, thickets, and gardens. It is an important pollinator for the temperate rainforest regions of southern South America. In elevation it ranges from sea level to above 2,000 m (6,600 ft).