Dusky Starfrontlet

The dusky starfrontlet is about 14 cm (5.5 in) long. Males weigh 6.9 to 7.2 g (0.24 to 0.25 oz) and females 6.7 to 7 g (0.24 to 0.25 oz). The male has a glittering blue-green to golden green forehead and a velvety black crown, face, and mantle. The back is green with black highlights, the rump and uppertail coverts iridescent golden green, and the tail a paler green. The throat and breast are dark green, like the back suffused with black, and there is a large cobalt-blue spot on the lower throat. The belly and undertail coverts are the same golden green as the rump. The female's crown, face, and upper back are green with blackish tips to the feathers that give a scaly effect. The rump, uppertail coverts, and tail are like the male's but with less iridescence. The throat is a bright cinnamon buff with green spots on the sides, the belly iridescent golden green with dusky inclusions, and the undertail coverts dull golden green with buffy edges. One Spanish name for the dusky starfrontlet is "Colibrí del Sol", which translates to "hummingbird of the Sun".

The dusky starfrontlet is found in only about a dozen sites in a few small areas of the Western Andes of Colombia. The original 1951 specimen and some of the 2004 ones were collected at Páramo de Frontino, Antioquia Department. Others were collected in 2004 at nearby Las Orquídeas National Natural Park in Farallones del Citará on the Antioquia/Chocó border. Further observations have come from Jardín in Antioquia and Cerro Montezuma in Risaralda Department. Specimens and sight records of dusky starfrontlet have come from tall humid forest, elfin forest, and the ecotone between forest and páramo. Most observations have been between about 3,100 and 3,500 m (10,200 and 11,500 ft) of elevation, but there is one record from 2,500 m (8,200 ft).

The dusky starfrontlet has been observed feeding on nectar at plants of genera Aetanthus, Bejaria, Bomarea, Cavendishia, and Centropogon. Stomachs of specimens have yielded spiders, wasps, flies, and what appeared to be a psocopteran.