The hillstars are hummingbirds of the genus Oreotrochilus. They are native to the Andes in South America.
Taxonomy The genus Oreotrochilus was introduced in 1847 by the English ornithologist John Gould with Trochilus estella d'Orbigny 1838, the Andean hillstar, as the type species. The genus name Oreotrochilus combines the Ancient Greek ορος/oros, ορεος/oreos meaning "mountain" with the genus Trochilus that had been introduced in 1758 by Carl Linnaeus for the hummingbirds.
The Urochroa hillstars are not closely related.
Species list Their genus contains seven species: Image Common name Scientific name DistributionEcuadorian hillstarOreotrochilus chimborazoBlue-throated hillstarOreotrochilus cyanolaemusGreen-headed hillstarOreotrochilus stolzmanniBlack-breasted hillstarOreotrochilus melanogasterAndean hillstarOreotrochilus estellaWhite-sided hillstarOreotrochilus leucopleurusWedge-tailed hillstarOreotrochilus adela
Description The birds are approximately in length with fairly long, slightly decurved black bills. They are sexually dimorphic. The male usually has an iridescent green throat, or bluish-purple in the Ecuadorian hillstar, with dull greenish upperparts and pale flanks. The central underparts are usually black, but are brown in the Andean hillstar. The tail is usually dark with a contrasting white pattern; the pattern is cinnamon in the wedge-tailed hillstar, and the tail is entirely dark in the black-breasted hillstar. The female is duller, with a whitish throat densely spotted with green, white, buff, or cinnamon underparts, and a dark tail with a white pattern.
Behaviour These highly territorial hummingbirds are found in temperate and alpine grassland, scrub and woodland at altitudes of . The Ecuadorian hillstar has been observed nesting at high altitudes on the cliffs of Cotopaxi.Smith, G. T. (1969). A high altitude hummingbird on the volcano Cotopaxi. Ibis 111(1), 17-22. This species is known to nest colonially.Solano-Ugalde, A. (2008). High in the Andes: Colonial nesting of Ecuadorean Hillstar (Oreotrochilus chimborazo: Trochilidae) under a bridge. Ornitología Colombiana 6, 86-88.
Many hillstars feed mainly on shrubs of the Andean plant genus Chuquiraga, and some species may be limited to them.Bleiweiss, R. (1982). The northern limit of the hummingbird genus Oreotrochilus in South America. The Auk 99(2), 376-78.
The genus has undergone allopatric speciation.
References
Further reading
Fjeldså, J. and I. Heynen (1999). Genus Oreotrochilus. pp. 623–24 In: del Hoyo, J., et al. (eds.) Handbook of the Birds of the World. Vol. 5. Barn-owls to Hummingbirds. Lynx Edicions, Barcelona. 1999.