The ornithologist John Gould described the species in 1869, from a specimen collected by H. Whitely at Tinta District, and placed it in its own genus Oreonympha. He recognised a kinship with Oxypogon and Ramphomicron. The genus name is derived from the Ancient Greek words oreo- "mountain" and "nympha" "nymph", while the specific epithet is the Latin adjective nobilis, "noble". A study of mitochondrial DNA of hummingbirds shows it to be most closely related to the bearded helmetcrest (Oxypogon guerinii) and the rufous-capped thornbill (Chalcostigma ruficeps). The other member of the genus Chalcostigma lay outside the group, suggesting the genus might need revising in the future. Two subspecies are recognised - the more widespread nominate subspecies nobilis has a blue eyebrow, while the more restricted albolimbata has white.
Measuring 15.5 to 16.5 cm (6-6.5 in) in length, it is a large hummingbird with a long tail and a 2.4 cm (1 in) long bill. The underparts of both sexes are white, while the tail is white underneath with black feather tips. The male has a green and purple throat. The upper parts are a bronze-sheened brown and the legs and bill are black.
The species is endemic to Peru, where it is found in high altitude valleys in the south-central Andes, from 2700 to 3900 m (9000–13000 ft). It lives in scrubland, and often visits tobacco (Nicotiana) plants along roadsides.
- BirdLife International (2012). "Oreonympha nobilis". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Gould, John (1869). "Description of a new genus and species of the family Trochilidae". Journal of zoology: 295–96.
- McGuire, Jimmy A.; Witt Christopher C.; Remsen, J. V. Jr; Dudley R.; Altshuler, Douglas L. (2008). "A higher-level taxonomy for hummingbird" (PDF). Journal of Ornithology 150: 155–65. doi:10.1007/s10336-008-0330-x.
- Schulenberg, Thomas S. (2007). Birds of Peru. Princeton, NJ: Princeton University Press. pp. 242–43. ISBN 0-691-13023-X. Retrieved 11 June 2011.