The blue-tailed emerald (''Chlorostilbon mellisugus'') is a

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

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

east of the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

from

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 ...

east to the

Guianas The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories: * French Guiana, an overseas department and region of France * ...

and

Trinidad Trinidad is the larger and more populous of the two major islands of Trinidad and Tobago. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is often referred to as the southernmos ...

, and south to northern

Bolivia , image_flag = Bandera de Bolivia (Estado).svg , flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center , flag_alt2 = 7 × 7 square p ...

and central

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

.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 blue-tailed emerald was formally described by the Swedish naturalist

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in 1758 in the tenth edition of his ''

Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomen ...

'' under the

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''Trochilus mellisugus''. The specific epithet combines the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''mel'' meaning "honey" and ''sugere'' meaning "to suck". Linnaeus's description was typically brief and it was unclear which species he was describing. When he updated his ''Systema Naturae'' for the twelfth edition in 1766 Linnaeus added citations including one to the "all-green humming-bird" that had been described and illustrated by the English naturalist George Edwards in his ''Gleanings of Natural History''. The identity still remained uncertain but in 1950 the American ornithologist

John T. Zimmer John Todd Zimmer (February 28, 1889 in Bridgeport, Ohio – January 6, 1957 in White Plains, New York) was a leading American ornithologist. A graduate of University of Nebraska-Lincoln, he took an early interest in both entomology and ornitholog ...

argued that the species ''Trochilus mellisugus'' described by Linnaeus could only have been the blue-tailed emerald. This has been generally accepted. Zimmer designated the type locality as

Cayenne Cayenne (; ; gcr, Kayenn) is the capital city of French Guiana, an overseas region and Overseas department, department of France located in South America. The city stands on a former island at the mouth of the Cayenne River on the Atlantic Oc ...

French Guiana French Guiana ( or ; french: link=no, Guyane ; gcr, label=French Guianese Creole, Lagwiyann ) is an overseas departments and regions of France, overseas department/region and single territorial collectivity of France on the northern Atlantic ...

. The blue-tailed emerald is now placed in the genus ''

Chlorostilbon ''Chlorostilbon'' is a genus of hummingbird in the family Trochilidae, known as emeralds (as are some hummingbirds in the genera '' Amazilia'' and '' Elvira''). A single species, the blue-chinned sapphire is variously placed in the monotypic g ...

'' that was introduced by the English ornithologist John Gould in 1853. The blue-tailed emerald has at times had as many as 17

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

assigned to it. Most of them have been reevaluated as individual species, as subspecies of other species, or as not being distinguishable at all.Bündgen, R., G. M. Kirwan, P. F. D. Boesman, and H. F. Greeney (2020). Blue-tailed Emerald (''Chlorostilbon mellisugus''), version 1.0. In Birds of the World (S. M. Billerman, B. K. Keeney, P. G. Rodewald, and T. S. Schulenberg, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.blteme1.01 retrieved August 1, 2022 Three major worldwide taxonomic systems differ in their treatment of the species. 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 ...

(IOC) recognizes seven subspecies. 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 ...

recognizes six and

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 ...

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 ...

(HBW) recognizes eight.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 Seven subspecies recognised by the IOC are: * ''C. m. caribaeus''

Lawrence Lawrence may refer to: Education Colleges and universities * Lawrence Technological University, a university in Southfield, Michigan, United States * Lawrence University, a liberal arts university in Appleton, Wisconsin, United States Preparator ...

, 1871 * ''C. m. duidae'' Zimmer, JT & Phelps, 1952 * ''C. m. subfurcatus'' Berlepsch, 1887 * ''C. m. mellisugus'' ( Linnaeus, 1758) * ''C. m. phoeopygus'' (

Tschudi Tschudi (variants: Schudy, Shoudy, Shudi, Schudi, Tschudy) is a surname common in the Canton of Glarus, Switzerland. History The Tschudi name can be traced back to 870. After Glarus joined the Swiss Confederation in 1352, various members of the fa ...

, 1844 * ''C. m. napensis''

Gould Gould may refer to: People * Gould (name), a surname Places United States * Gould, Arkansas, a city * Gould, Colorado, an unincorporated community * Gould, Ohio, an unincorporated community * Gould, Oklahoma, a town * Gould, West Virginia, a ...

, 1861 * ''C. m. peruanus'' Gould, 1861 The Clements taxonomy and HBW include ''napensis'' within ''phoeopygus'', considering them indistinguisable from each other. However, HBW's subspecies include ''C. m. pumilis'' and ''C. m. melanorhynchus''. Clements assigns those two subspecies to the

western emerald The western emerald (''Chlorostilbon melanorhynchus'') is a species of hummingbird in the "emeralds", tribe Trochilini of subfamily Trochilinae. It is found in Colombia and Ecuador. Taxonomy and systematics The western emerald was originally ...

(''C. melanorhynchus''), which the IOC also recognizes. However, the IOC does not recognize ''pumilis'' and treats the western emerald as

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 ...

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 ...

studies suggest that the blue-tailed emerald is sister to the glittering-bellied emerald. However, the IOC, Clements, and HBW do not appear to have fully accepted that treatment, as their linear sequences of species (which reflect relationships) insert the

Chiribiquete emerald The Chiribiquete emerald (''Chlorostilbon olivaresi'') is a species of hummingbird in the "emeralds", tribe Trochilini of subfamily Trochilinae. It is endemic to southern Colombia.HBW and BirdLife International (2020) ''Handbook of the Birds of ...

(''C. olivaresi'') between the two.

Description

Male blue-tailed emeralds are long and females . Males of ''C. m. caribaeus'' average about and females about . Males of ''C. m. phoeopygus'' average about and females about . Both sexes of all subspecies have a short, straight, black bill. All of the males have a forked tail whose depth varies somewhat among the subspecies. Females are essentially indistinguisable from each other. Males of the nominate subspecies have an iridescent golden green forehead and crown, shining bronze-green upperparts, and a steel blue tail. Their underparts are glittering emerald green that is most iridescent on the breast and bluish on the throat. They have white thighs. The nominate female's forehead and crown are bronzy green. Its face has a blackish "mask" with a pale gray stripe behind the eye. The rest of its upperparts are metallic grass green and the tail blue-black with whitish gray tips. Its underparts are pale gray. Subspecies ''C. m. caribaeus'' is very like the nominate but the male has less blue on its throat. Male ''C. m. duidae''s have a bronzy orange head and reddish copper upperparts. Males of ''C. m. subfurcatus'' have blue-green on the throat and 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 golden green on the crown whose intensities are intermediate between the nominate and ''caribaeus''. ''C. m. phoeopygus'' has a deeper fork to the tail than the nominate. ''C. m. peruanus'' looks essentially the same as the nominate.

Distribution and habitat

The seven subspecies of blue-tailed emerald recognized by the IOC are distributed thus: * ''C. m. caribaeus'', northern Venezuela, Trinidad, and the " ABC Islands" * ''C. m. duidae'', Cerro Duida region of southern Venezuela's Amazonas state * ''C. m. subfurcatus'', eastern and southern Venezuela, Guyana, and the Rio Branco region of northwestern Brazil * ''C. m. mellisugus'', Suriname, French Guiana, and the lower Amazon basin of northeastern Brazil * ''C. m. phoeopygus'', the upper Amazon River and its eastern tributaries in Colombia, Ecuador, and Brazil * ''C. m. napensis'', the upper Amazon River in northeastern Peru * ''C. m. peruanus'', southeastern Peru, eastern Bolivia, and possibly extreme southwestern Brazil The species occurs in a variety of habitats from the tropical to the temperate zones. It mostly is found in semi-open to open landscapes such as savanna, '' cerrado'', cultivated areas, and gardens. It also occurs in the edges of deciduous woodland and in large clearings within ''

terra firme Terra may often refer to: * Terra (mythology), primeval Roman goddess * An alternate name for planet Earth, as well as the Latin name for the planet Terra may also refer to: Geography Astronomy * Terra (satellite), a multi-national NASA scienti ...

'' forest, and commonly in Ecuador, '' Várzea'' and floodplain forest. In elevation it ranges between in Ecuador, up to in Peru, and from sea level to about in Venezuela.

Behavior

Movement

The blue-tailed emerald is mostly sedentary but in some areas apparently makes seasonal movements.

Feeding

The blue-tailed emerald forages for nectar mostly 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 ...

, visiting a circuit of flowering plants. However, in some areas it defends patches of flowers. It takes nectar from a very wide variety of low plants, shubs, and trees, and feeds at all levels of the vegetation. In addition to nectar, it captures small insects and other arthropodshttps://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/documents/ogatt/Chlorostilbon_mellisugus%20-%20Blue-tailed%20Emerald.pdf 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. Chlorostilbon mellisugus

Breeding

The blue-tailed emerald's northernmost subspecies ''C. m. caribaeus'' appears to nest at any time of year. The other subspecies' breeding seasons have not been documented. The species makes a cup nest of downy plant material bound with spiderweb and covered with bits of bark and lichen. It tends to place it on a sloping branch within about of the ground in dense second-growth vegetation. The female incubates the clutch of two eggs for 13 to 19 days and fledging occurs 18 to 20 days after hatch.

Vocalization

The blue-tailed emerald's song has been described as "repeated 'tsip' or ''chwep'' notes, with occasional rolls or twitters". Its calls include "a relatively loud and harsh ''chirrrt'' and "soft 'tsip', 'pit' and 'chwep'" notes.

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 ...

follows HBW taxonomy and so includes what IOC and Clements calls the western emerald. It has assessed the blue-tailed emerald as being of Least Concern. It has a very large range, and though its population size is not known it is believed to be stable. It is considered common across much of its range though less so on Trinidad and eastern Ecuador. It occurs in several protected areas and has adapted to human-made landscapes.