The narrow-tailed emerald (''Chlorostilbon stenurus'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

hummingbird Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. With about 361 species and 113 genera, they occur from Alaska to Tierra del Fuego, but the vast majority of the species are found in the tropics aro ...

in the "emeralds", tribe Trochilini of subfamily Trochilinae. It is found in

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

and

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

.HBW and BirdLife International (2020) ''Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world'' Version 5. Available at: http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v5_Dec20.zip xls zipped 1 MBretrieved 27 May 2021

Taxonomy and systematics

The narrow-tailed emerald has two subspecies, the nominate ''C. s. stenurus'' and ''C. s. ignotus''. At least one author has suggested that the

green-tailed emerald The green-tailed emerald (''Chlorostilbon alice'') is a species of hummingbird in the "emeralds", tribe Trochilini of subfamily Trochilinae. It is endemic to Venezuela. Taxonomy and systematics The green-tailed emerald was originally describ ...

(''C. alice'') is either a third subspecies or is contained within ''ignotus''.Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, A. Jaramillo, D. F. Lane, J. F. Pacheco, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 24 July 2022. A classification of the bird species of South America. American Ornithological Society. https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm retrieved July 24, 2022Bündgen, R. and P. F. D. Boesman (2020). Narrow-tailed Emerald (''Chlorostilbon stenurus''), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.nateme2.01 retrieved August 2, 2022

Description

The male narrow-tailed emerald is long and females . The species weighs between . Males of both subspecies have a short, straight, black bill. Males of the nominate subspecies have shining green forehead and crown, shining grass green upperparts including the uppertail

coverts A covert feather or tectrix on a bird is one of a set of feathers, called coverts (or ''tectrices''), which, as the name implies, cover other feathers. The coverts help to smooth airflow over the wings and tail. Ear coverts The ear coverts are sm ...

, and iridescent green underparts and flanks. Its tail is forked and dark green; the outer pair of feathers are very small and stiletto shaped. Females have a slightly decurved bill. Nominate females have a dull dark green crown with a bronze tinge and dark green upperparts and uppertail coverts. Their chin is brownish, the throat pale white, and the rest of the underparts a somewhat darker white. Their tail is forked. Its two innermost pairs of feathers are metallic bluish green. The next pair have metallic green bases becoming brown before the white tip. The outermost two pairs have gray bases becoming dark blue before the wide white tip. Males of subspecies ''C. s. ignotus'' are very similar to the nominate, but are smaller, more yellowish green above, and have a duller, darker green, tail.

Distribution and habitat

The nominate subspecies of narrow-tailed emerald is found in the Andes of northwestern Venezuela from Trujillo state west into Colombia's Meta Department. ''C. s. ignotus'' is found from the coastal mountains of Venezuela south into Lara state. The species inhabits humid forest, scrublands, and

secondary forest A secondary forest (or second-growth forest) is a forest or woodland area which has re-grown after a timber harvest or clearing for agriculture, until a long enough period has passed so that the effects of the disturbance are no longer evident. ...

between elevations of .

Behavior

Movement

The narrow-tailed emerald is generally sedentary but locally makes seasonal elevational changes.

Feeding

The narrow-tailed emerald forages for nectar by

trap-lining In ethology and behavioral ecology, trap-lining or traplining is a feeding strategy in which an individual visits food sources on a regular, repeatable sequence, much as trappers check their lines of traps. Traplining is usually seen in species ...

in fairly open areas, visiting a circuit of a variety of flowering plants such as Ericaceae, Rubiaceae, Heliconiaceae,

Gesneriaceae Gesneriaceae, the gesneriad family, is a family of flowering plants consisting of about 152 genera and ca. 3,540 species in the tropics and subtropics of the Old World (almost all Didymocarpoideae) and the New World (most Gesnerioideae), with ...

, and '' Inga''. It generally forages low, between above the ground. It captures small insects by

hawking Hawking may refer to: People * Stephen Hawking (1942–2018), English theoretical physicist and cosmologist *Hawking (surname), a family name (including a list of other persons with the name) Film * ''Hawking'' (2004 film), about Stephen Haw ...

from a perch.

Breeding

The narrow-tailed emerald's breeding season spans from September to November. It builds a cup nest of moss with lichen on the outside and typically places it in a shrub or tree between above the ground. The female incubates the clutch of two eggs for 15 to 16 days and fledging occurs about 20 days after hatch.

Vocalization

As of mid-2022, neither the Cornell Lab of Ornithology's Macaulay Library nor

xeno-canto xeno-canto is a citizen science project and Information repository, repository in which volunteers record, upload and annotate recordings of Bird vocalization, birdsong and bird calls. Since it began in 2005, it has collected over 575,000 sound r ...

have recordings of the narrow-tailed emerald's vocalizations.

Status

The

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has assessed the narrow-tailed emerald as being of Least Concern, though it has a limited range and its population size and trend are unknown. No immediate threats have been identified. It is considered common throughout its range and is comfortable in human-made habitats.

References

{{Taxonbar, from=Q1264627 narrow-tailed emerald Birds of the Colombian Andes Birds of the Venezuelan Andes narrow-tailed emerald Taxonomy articles created by Polbot