Blue-mantled thornbill

Appearance

The blue-mantled thornbill is 12 to 13 cm long; males weigh about 6.2 g and females 4.5 g. Both sexes have a short straight black bill and a small white spot behind the eye. Adult males of the nominate subspecies are generally dark sooty brown. The crown and nape have a bronzy green sheen, the back reflects violet-blue, and the uppertail coverts are turquoise. The forked tail is steel blue. They have a narrow gorget that is emerald green on the chin and transitions through pink to purple-violet or violet-blue at the lower edge. Adult females are similar, but the gorget has only the green under the chin and the outer tail feathers have pale tips. Juveniles resemble the adult female.

Subspecies "C. s. versigulare"'s entire upperparts reflect deep violet-blue, and the lower pink to violet of the gorget is narrower than in the nominate. "C. s. vulcani" is similar to "versigulare" but the lower part of its gorget becomes blue-gray or gray-violet.

Distribution

The nominate subspecies of blue-mantled thornbill is found on both slopes of the Andes of Ecuador between the departments of Carchi and Azauy. "C. s. versigulare" is found on the Peruvian Andes' east slope from east of the Marañón River south to the Cordillera Carpish in Huánuco Department and also in the Cordillera Blanca on the west slope. "C. s. vulcani" is found on the eastern Andean slope from southern Peru to Cochabamba Department in central Bolivia.

Status

The IUCN has assesed the blue-mantled thornbill as being of Least Concern. It has a large range but its population size is unknown and believed to be decreasing. Though it is generally fairly common, it is locally under threat by destruction of "Polylepis" woodlands and conversion of natural grasslands to pasture.

Habitat

The blue-mantled thornbill inhabits steep, rocky slopes with somewhat humid "páramo" grasslands and "jalca" vegetation. Within those landscapes it favors patches of "Polylepis" and "Gynoxys" woodland. In elevation it generally occurs between 3,000 and 4,200 m but has been recorded as low as 2,200 m and as high as 4,500 m.

Reproduction

The blue-mantled thornbill is believed to breed during the rainy season. As is typical of hummingbirds, the female alone incubates the two white eggs. Nothing else has been documented about its breeding phenology.

Food

The blue-mantled thornbill feeds on the nectar of small flowers such as "Berberis", "Gaultheria", "Ribes", and "Gentiana". It defends feeding territories. It has been observed gleaning tiny insects from the underside of "Gynoxys" leaves while clinging to them. It also picks insects from matted grass or rocks by hopping among them, and occasionally sallies to take insects on the wing.