Three subspecies are currently recognized: C. s. stanleyi (Bourcier, 1851), C. s. versigulare (J. T. Zimmer, 1924), and C. s. vulcani (Gould, 1852).
The species has a dark blue and green back and wing feathers, and a dark brown and green body. The crissum (the undertail coverts surrounding the cloaca) is cinnamon with a scaly pattern. A thin green and purple strip is found on the throat and a small part of the breast in males. There is a white line in the corner of the eye, and white down feathers are present near the vent. The needle-like beak, specialized for extracting nectar from small flowers (including the genera Berberis, Gaultheria, Ribes, and Gentiana), is about the same size as the head and black in color. As other hummingbird species, the blue-mantled thornbill also feeds on insects. Total size varies between 11 and 13 cm; the tail is about half as long as the body. Males weigh about 6.2 g and females about 4.5 g. The species breeds during the rainy season, incubating two eggs.
Distribution and habitat
The blue-manteled thornbill generally occurs at altitudes of 3000–4200 m in Ecuador, Bolivia, and Perú, but has also been reported at slightly lower or higher elevations (2200–4500 m). Their area of distribution is approximately 117,000 km2. The species migrates to lower elevations in the rainy season.
The blue-manteled thornbill's habitat is subtropical or tropical moist montane forests and high altitude shrublands, and mainly in subtropical and tropical high altitude grasslands. It does not necessarily depend on the presence of forest, and may be found in páramo grasslands, humid Polylepis woodlands, near jalca vegetation, and in steep rocky terrain. C.s. stanleyi is found on the Andean slopes of Ecuador from Carchi to Azuay; C.s. versigulare on the eastern slopes from Perú south to the Cordillera Carpish (Huánuco), and the western slope of the Cordillera Blanca; and C. s. vulcani on the eastern slopes from south Perú to Cochabamba in Bolivia.
The blue-mantled thornbill has been classified as Least Concern by the IUCN based on its wide distribution and large population numbers. However, populations are decreasing mainly due to habitat loss driven by deforestation for agricultural expansion and logging mainly of Polylepis woods.
- BirdLife International (2012). "Chalcostigma stanleyi". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- "Chalcostigma stanleyi versigulare". Avibase. Retrieved 2016-09-30.
- McMullan, Miles; Navarrete, Lelis (2013). Fieldbook of the Birds of Ecuador. Quito, Ecuador: Jocotoco. p. 80. ISBN 978 0982 7615 33.
- "Blue-mantled Thornbill (Chalcostigma stanleyi)". Handbook of the Birds of the World. Retrieved 2016-09-30.
- Graham, Catherine; Parra, Juan; Rahbek, Carsten; McGuire, Jimmy (2009). "Phylogenetic Structure in Tropical Hummingbird Communities". 106. National Academy of Sciences. JSTOR 25593253.
- Vogt, C. (2006). "High-elevation records of bird species from Rucu Pichincha Volcano, Ecuador". Cotinga. 26: 81–83.
- "Blue-mantled Thornbill (Chalcostigma stanleyi)". BirdLife International. Retrieved 2016-09-30.
- "Blue-mantled Thornbill (Chalcostigma stanleyi)". Cornell Lab of Ornithology - Neotropical Birds. Retrieved 2016-09-30.