Green-backed Firecrown

Characterized by a compact body and a length ranging from 10 to 11 centimeters (approximately 3.9 to 4.3 inches), this small avian species weighs about 5.5 grams. It exhibits distinct sexual dimorphism, primarily defined by the male´s striking, highly iridescent fire-red or ruby-orange crown on its forehead and crown, which shimmers intensely depending on the angle of sunlight; females completely lack this brilliant crown. The upperparts of both sexes are a metallic bronzy-green, while the underparts present a pale grayish-white coloration covered with dark, fine speckling. The bill is short, straight, and black, specifically evolved to probe tubular flowers of moderate depth.

Geographical distribution: This species is widely distributed throughout the southern cone of South America, spanning from the Atacama region in northern Chile to the southern tip of Tierra del Fuego in both Chile and southwestern Argentina. It is also resident or vagrant in the Juan Fernández Archipelago. During the cold winter months, southern populations undergo significant latitudinal and altitudinal migrations, moving northward and toward lower elevations into central and northern areas of its range to locate stable food resources.

Habitat: Primarily frequents the temperate Valdivian rainforests and the subantarctic Nothofagus forests of Patagonia. However, it displays remarkable ecological adaptability, commonly occupying sclerophyllous scrublands, forest edges, humid ravines, urban parks, residential gardens, and agricultural landscapes, ranging from sea level up to elevations of 2,000 meters where flowering plants are abundant.

Feeding: Maintains a highly specialized nectarivorous diet, which is regularly supplemented with small arthropods. It serves as an essential ecological pollinator for numerous native plants in southern temperate forests, including the firebush (Embothrium coccineum), the hardy fuchsia (Fuchsia magellanica), and the copihue (Lapageria rosea). To satisfy its high protein, amino acid, and lipid requirements needed to sustain its rapid metabolism, it actively hunts insects and spiders via flycatching or gleaning from foliage.

Behavior: Displays highly territorial and aggressive behaviors, fiercely defending productive nectar sources from other hummingbirds and even larger avian species. Its flight is exceptionally agile, allowing for hovering, backward flight, and rapid aerial maneuvers. To cope with the freezing night temperatures of its southern habitat, this bird enters a state of nocturnal torpor, dramatically lowering its metabolic rate, heart rate, and body temperature to conserve vital energy reserves.

Nesting: Breeding occurs mainly between September and January. The female is solely responsible for constructing a neat, compact, cup-shaped nest using mosses, lichens, and fine plant fibers, bound together securely with spiderwebs. These nests are typically suspended from low branches of bushes, ferns, or forest undergrowth trees, often close to water sources. The female usually lays two white, elliptical eggs, incubating them for 14 to 18 days. The altricial nestlings are cared for by the female and fledge after approximately three weeks.

Conservation status: Classified as Least Concern (LC) on the IUCN Red List of Threatened Species. Although currently widespread and relatively common throughout its range, its long-term survival is threatened by habitat fragmentation, deforestation of native temperate woodlands, and the consequences of climate change, which disrupt the crucial flowering phenology of its primary food plants.