About Discosura popelairii (Du Bus de Gisignies, 1846)
This species, the wire-crested thorntail, is one of the smallest birds on Earth. Mature individuals weigh approximately 2.5 g (0.088 oz). Males measure about 11.4 cm (4.5 in) long when including the tail extension, while females measure between 7.5 and 8.2 cm (3.0 to 3.2 in) long.
Adult birds of both sexes have coppery green upperparts, with a white band running across the rump. Males have a glittering green crown that bears a thin, hair-like crest. They have an iridescent green gorget, brownish flanks with a white patch, and black on the rest of their underparts. The male's tail is steely blue with white feather shafts, and is deeply forked; its outer feathers are very narrow, and this feature along with the crest gives the species its common name. Females lack the crest. They have a broad white streak on the cheek, black underparts with a white flank patch, and a short, only slightly forked bluish black tail with white tips. Juvenile wire-crested thorntails are similar in appearance to adult females.
The wire-crested thorntail is found in Andean foothills, ranging from eastern Colombia's Meta Department through eastern Ecuador and into eastern Peru as far south as the Department of Puno. There is also at least one documented sight record of the species in Bolivia. It inhabits both the edges and the interior of humid forest, at elevations between 500 and 1,500 m (1,600 and 4,900 ft).
