Purple-backed Thornbill

Identification

The purple-backed thornbill is a tiny hummingbird, measuring just 8 to 9 cm in length and weighing approximately 3.5 g, making it one of the smallest members of its family. It is instantly recognizable by its exceptionally short black bill—the shortest of any hummingbird species. Males of the nominate subspecies display metallic violet-purple upperparts with a distinctive white spot behind the eye, an iridescent golden-green gorget, bronzy-green underparts, and dark purple tail feathers that are moderately long and forked. Females have shining green upperparts, also with the characteristic white eye-spot, white underparts dotted with green, and a shorter, less deeply forked tail with white-tipped outer feathers. Subspecific variation occurs across the species' range, with some males showing green-bordered gorgets or darker underparts depending on their geographic origin.

Range & Habitat

The purple-backed thornbill is endemic to the Andes mountains, with four subspecies distributed across Colombia, Ecuador, Peru, Bolivia, and Venezuela. The nominate subspecies occurs in the Andes of Colombia, Ecuador, and northwestern Peru, while other subspecies inhabit the western Venezuelan Andes, the eastern Andean slopes of Peru, and the central Bolivian highlands. The species occupies a narrow elevational band between 1,700 and 3,600 m, frequenting the edges of humid montane forest, Polylepis (queñoa) woodland, páramo grassland, and transitional zones between these habitats. One subspecies also ranges into shrubby areas well below the treeline.

Behaviour & Diet

The purple-backed thornbill employs a trap-lining feeding strategy, moving methodically between flowering plants to harvest nectar from mid-level to canopy heights. It opportunistically exploits feeding holes created by Diglossa flowerpiercers, a behavior known as nectar robbing, and also takes insects both in flight and by gleaning from flowers. The species exhibits altitudinal migration, moving from lower to higher elevations during the wet season. Breeding occurs from May through December, with pairs constructing delicate cup nests of fine plant fibers decorated with moss and lichen on horizontal branches. Each clutch comprises two eggs with an incubation period of 16 days. Males produce a distinctive song described as a continuous series of quiet scratchy notes interspersed with short buzzes and dry trills, complemented by various calls including sharp rattles and twittering notes.

Best Time & Places to See It

The purple-backed thornbill is generally uncommon throughout its range, though more regularly encountered at higher elevations during the breeding season from May onwards. The wet season movement to higher elevations offers the best viewing opportunities in montane forest edges and páramo transitions. Several protected areas within its range provide habitat for this species, though populations outside protected zones face severe deforestation pressures. Visiting the appropriate elevations (1,700–3,600 m) during the breeding season in the Venezuelan, Colombian, Ecuadorian, or Peruvian Andes offers the most reliable chance of encounters.

Photography Tips

Photographing this diminutive thornbill requires patience and fast shutter speeds, as the species feeds actively and moves with typical hummingbird agility. The white eye-spot provides a useful identification feature and point of focus for portraits. The iridescent gorget of males responds dramatically to light angle—position yourself to capture side-lighting that illuminates the golden-green throat display. The bird's preference for mid-canopy feeding means positioning yourself at appropriate elevations and watching flowering plants and trees for visiting birds. Early morning light in montane forest edges yields the best color saturation of the male's metallic purple upperparts.