The white-tailed emerald (''Microchera chionura'') is a species of

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

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

and

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cos ...

.HBW and BirdLife International (2021) Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 6. Available at: http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v6_Dec21.zip retrieved August 7, 2022

Taxonomy and systematics

The white-tailed emerald was formerly placed with the coppery-headed emerald in the genus ''Elvira''. A

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study published in 2014 found that these two species were closely related to the

snowcap The snowcap (''Microchera albocoronata'') is a species of hummingbird in the "emeralds", tribe Trochilini of subfamily Trochilinae. It is found in Costa Rica, Honduras, Nicaragua, and Panama.HBW and BirdLife International (2021) Handbook of th ...

in the then-

monospecific In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus ''

Microchera ''Microchera'' is a genus of hummingbirds. Species The genus includes three species: *Snowcap, ''Microchera albocoronata'' * Coppery-headed emerald, ''Microchera cupreiceps'' * White-tailed emerald, ''Microchera chionura'' The white-tailed eme ...

''. The

International Ornithological Committee The International Ornithologists' Union, formerly known as the International Ornithological Committee, is a group of about 200 international ornithologists, and is responsible for the International Ornithological Congress and other international ...

and the

Clements taxonomy ''The Clements Checklist of Birds of the World'' is a book by Jim Clements which presents a list of the bird species of the world. The most recent printed version is the sixth edition (2007), but has been updated yearly, the last version in 2022 ...

placed the three species together in ''Microchera'' which has priority. However,

BirdLife International BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding ...

's ''

Handbook of the Birds of the World The ''Handbook of the Birds of the World'' (HBW) is a multi-volume series produced by the Spanish publishing house Lynx Edicions in partnership with BirdLife International. It is the first handbook to cover every known living species of bird. T ...

'' retains them in ''Elvira''.Clements, J. F., T. S. Schulenberg, M. J. Iliff, S. M. Billerman, T. A. Fredericks, J. A. Gerbracht, D. Lepage, B. L. Sullivan, and C. L. Wood. 2021. The eBird/Clements checklist of Birds of the World: v2021. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/ Retrieved August 25, 2021 The white-tailed emerald is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

Description

The white-tailed emerald is long. Males weigh about and females . Both sexes have an almost straight black bill whose

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...

has a pinkish base. The adult male has bronzy green upperparts that becomes dark copper-bronze on 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 ...

. Its central two pairs of tail feathers are copper-bronze and the other three pairs white with black tips. It has a glittering green throat and chest and white belly, vent, and undertail coverts. The adult female also has bronzy green upperparts. Its central two pairs of tail feathers are bronzy and the other three pairs white with a black band near the tip. Its underparts are dull white with bronzy green flanks. The immature male is similar to the adult but with duller underparts that have grayish buff fringes to the feathers. Immature females have grayer underparts than the adult.Stiles, F.G. and P. F. D. Boesman (2021). White-tailed Emerald (''Microchera chionura''), version 1.1. 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.whteme1.01.1 retrieved August 28, 2022

Distribution and habitat

The white-tailed emerald is found in the highlands of the Pacific slope from south-central Costa Rica to central Panama and also locally on the Caribbean slope in Panama. It inhabits the edges and interior of moist to humid

montane forest Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial f ...

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. ...

, and also plantations and gardens. In the forest interior males are often found in the canopy and females in the understory. In elevation it ranges from but in Costa Rica breeds mostly between .

Behavior

Movement

The white-tailed emerald's movements are not fully understood. In Costa Rica some individuals move both upslope and down outside the breeding season.

Feeding

The white-tailed emerald feeds on nectar from a variety of flowering plants at both the edges and interior of the forest. In addition to nectar, it captures small

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

s 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 white-tailed emerald's breeding season extends from June to November. Males court females at

leks A lek is an aggregation of male animals gathered to engage in competitive displays and courtship rituals, known as lekking, to entice visiting females which are surveying prospective partners with which to mate. A lek can also indicate an avail ...

in small groups. Nothing else is known about the species' breeding

phenology Phenology is the study of periodic events in biological life cycles and how these are influenced by seasonality, seasonal and interannual variations in climate, as well as environmental factor, habitat factors (such as elevation). Examples includ ...

and its nest has not been described.

Vocalization

The white-tailed emerald's song is "a prolonged, thin scratchy twittering mixed with buzzing or gurgling notes". It also makes "soft scratchy chipping notes" when foraging and "high-pitched, buzzy notes" when chasing.

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 white-tailed emerald as being of Least Concern. Its population is estimated to be at least 20,000 mature individuals and stable. No immediate threats have been identified. It is considered locally common in some protected areas, but "deforestation sextensive and continuing in at least the lower part of its altitudinal range".

References

{{Taxonbar, from=Q1262766 white-tailed emerald Birds of the Talamancan montane forests white-tailed emerald Taxonomy articles created by Polbot Taxobox binomials not recognized by IUCN