Blue-tailed emerald

{{speciesbox | image = Blue-tailed Emerald - Ecuador S4E0715.jpg | status = LC | status_system = IUCN3.1 | status_ref = <ref name=IUCN>{{cite iucn |author=BirdLife International |author-link=BirdLife International |year= 2017 |title= ''Chlorostilbon mellisugus'' |amends= 2016 |article-number= e.T22687313A112399190 |doi=10.2305/IUCN.UK.2017-1.RLTS.T22687313A112399190.en |access-date=1 August 2022}}</ref> | status2 = CITES_A2 | status2_system = CITES | status2_ref = <ref>{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org}}</ref> | genus = Chlorostilbon | species = mellisugus | authority = (Linnaeus, 1758) | synonyms = ''Trochilus mellisugus'' {{small|Linnaeus, 1758}}<br /> ''Ornismya prasina'' {{small|Lesson, 1830}}<br /> ''Chlorostilbon brevicaudatus'' {{small|Gould, 1861}} | range_map = Chlorostilbon mellisugus map.svg }}

The '''blue-tailed emerald''' ('''''Chlorostilbon mellisugus''''') is a hummingbird in the "emeralds", tribe Trochilini of subfamily Trochilinae. It is found in tropical and subtropical South America east of the Andes from Colombia east to the Guianas and Trinidad, and south to northern Bolivia and central Brazil.<ref name=IOC13.2>{{cite web |url=https://www.worldbirdnames.org/new/bow/hummingbirds/ |title=Hummingbirds |website=IOC World Bird List |version =v 13.2 |editor-last1=Gill |editor-first1= F. |editor1-link=Frank Gill (ornithologist) |editor-last2=Donsker|editor-first2=D.|editor-last3=Rasmussen |editor-first3=P. |date=2023 |access-date=13 December 2023}}</ref><ref name="HBW2020">{{Cite book |url=http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v5_Dec20.zip |title=Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world |publisher=HBW and BirdLife International |year=2020 |edition=5}}</ref>

==Taxonomy and systematics==

The blue-tailed emerald was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his ''Systema Naturae'' under the binomial name ''Trochilus mellisugus''.<ref>{{cite book | last=Linnaeus | first=Carl | author-link=Carl Linnaeus | year=1758 | title= Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis | volume=1 | edition=10th | page=121 | publisher=Laurentii Salvii | place=Holmiae (Stockholm) | language=Latin | url=https://www.biodiversitylibrary.org/page/727026 }}</ref> The specific epithet combines the Latin ''mel'' meaning "honey" and ''sugere'' meaning "to suck".<ref>{{cite book | last=Jobling | first=James A. | year=2010| title=The Helm Dictionary of Scientific Bird Names | publisher=Christopher Helm | location=London | isbn=978-1-4081-2501-4 | page=249 }}</ref> 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''.<ref>{{cite book | last=Linnaeus | first=Carl | author-link=Carl Linnaeus | year=1766 | title=Systema naturae: per regna tria natura, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis | edition=12th | volume=1, Part 1 | publisher=Laurentii Salvii | place=Holmiae (Stockholm) | language=Latin | page=192 | url=https://www.biodiversitylibrary.org/page/42946388 }}</ref><ref>{{ cite book | last=Edwards | first=George | author-link=George Edwards (naturalist) | year=1758–1764 | title=Gleanings of Natural History, exhibiting figures of quadrupeds, birds, insects, plants &c... | language=English, French | volume=Part 3 | place=London | publisher=Printed for the author, at the College of Physicians | url=https://www.biodiversitylibrary.org/page/50176661 | pages=316–318, Plate 360 fig. 1 }}</ref> The identity still remained uncertain but in 1950 the American ornithologist John T. Zimmer argued that the species ''Trochilus mellisugus'' described by Linnaeus could only have been the blue-tailed emerald.<ref name=zimmer>{{ cite journal | last=Zimmer | first=John Todd | author-link=John T. Zimmer | date=10 November 1950 | title=Studies of Peruvian birds. No. 58. The genera ''Chlorostilbon'', ''Thalurania'', ''Hylocharis'' and ''Chrysuronia'' | journal=American Museum Novitates |issue=1474 | pages=4–5 | hdl=2246/4385 | url=http://digitallibrary.amnh.org/handle/2246/4385 }}</ref> This has been generally accepted.<ref name=IOC13.2/> Zimmer designated the type locality as Cayenne in French Guiana.<ref name=zimmer/> The blue-tailed emerald is now placed in the genus ''Chlorostilbon'' that was introduced by the English ornithologist John Gould in 1853.<ref name=IOC13.2/><ref>{{ cite book | last=Gould | first=John | author-link=John Gould | year=1853 | title=A Monograph of the Trochilidae, or Family of Humming-Birds | volume=5 | location=London | publisher=self | at=Plate 355 and text (Part 5 Plate 14) | url=https://www.biodiversitylibrary.org/page/34998935 }} The 5 volumes were issued in 25 parts between 1849 and 1861. Title pages of all volumes bear the date of 1861.</ref>

The blue-tailed emerald has at times had as many as 17 subspecies assigned to it. Most of them have been reevaluated as individual species, as subspecies of other species, or as not being distinguishable at all.<ref name="BTEM-BOW">{{Cite journal |last1=Bündgen |first1=Ralf |last2=Kirwan |first2=Guy M. |last3=Boesman |first3=Peter F. D. |last4=Greeney |first4=Harold F. |date=2020 |title=Blue-tailed Emerald (Chlorostilbon mellisugus), version 1.0 |url=https://birdsoftheworld.org/bow/species/blteme1/cur/introduction |journal=Birds of the World |language=en |doi=10.2173/bow.blteme1.01 |issn=2771-3105|url-access=subscription }}</ref>

Three major worldwide taxonomic systems differ in their treatment of the species. The International Ornithological Committee (IOC) recognizes seven subspecies. The Clements taxonomy recognizes six and BirdLife International's Handbook of the Birds of the World (HBW) recognizes eight.<ref name=IOC13.2/><ref name="Clements">{{Cite web |title=2023 Citation & Downloadable Checklists – Clements Checklist |url=https://www.birds.cornell.edu/clementschecklist/introduction/updateindex/october-2023/download/ |access-date=2024-08-09 |website=www.birds.cornell.edu}}</ref><ref name=HBW2020/>

Seven subspecies recognised by the IOC are:<ref name=IOC13.2/>

* ''C. m. caribaeus'' Lawrence, 1871 * ''C. m. duidae'' Zimmer, JT & Phelps, 1952 * ''C. m. subfurcatus'' Berlepsch, 1887 * ''C. m. mellisugus'' (Linnaeus, 1758) * ''C. m. phoeopygus'' (Tschudi, 1844 * ''C. m. napensis'' Gould, 1861 * ''C. m. peruanus'' Gould, 1861

The Clements taxonomy and HBW include ''napensis'' within ''phoeopygus'', considering them indistinguishable from each other. However, HBW's subspecies include ''C. m. pumilis'' and ''C. m. melanorhynchus''. Clements assigns those two subspecies to the western emerald (''C. melanorhynchus''), which the IOC also recognizes. However, the IOC does not recognize ''pumilis'' and treats the western emerald as monotypic.<ref name=Clements/><ref name=HBW2020/><ref name=IOC13.2/>

Molecular phylogenetic studies suggest that the blue-tailed emerald is sister to the glittering-bellied emerald.<ref name=mcguire2014>{{ cite journal | last1=McGuire | first1=J. | last2=Witt | first2=C. | last3=Remsen | first3=J.V. | last4=Corl | first4=A. | last5=Rabosky | first5=D. | last6=Altshuler | first6=D. | last7=Dudley | first7=R. | date=2014 | title=Molecular phylogenetics and the diversification of hummingbirds | journal=Current Biology | volume=24 | issue=8 | pages=910–916 | doi=10.1016/j.cub.2014.03.016 | pmid=24704078 | doi-access=free | bibcode=2014CBio...24..910M }}</ref><ref name=stiles2017b>{{ cite journal | last1=Stiles | first1=F.G. | last2=Remsen | first2=J.V. Jr. | last3=Mcguire | first3=J.A. | year=2017 | title=The generic classification of the Trochilini (Aves: Trochilidae): Reconciling taxonomy with phylogeny | journal=Zootaxa | volume=4353 | issue=3 | pages=401–424 | doi=10.11646/zootaxa.4353.3.1 | pmid=29245495 | url=https://www.researchgate.net/publication/321277435 }}</ref><ref>{{Cite journal | last1=Hernández-Baños | first1=B.E. | last2=Zamudio-Beltrán | first2=L.E. | last3=Milá | first3=B. | date=2020 | title=Phylogenetic relationships and systematics of a subclade of Mesoamerican emerald hummingbirds (Aves: Trochilidae: Trochilini) | journal=Zootaxa | volume=4748 | issue=3 | pages=581–591 | doi=10.11646/zootaxa.4748.3.11| pmid=32230070 | s2cid=214748801 }}</ref> 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 (''C. olivaresi'') between the two.<ref name=IOC13.2/><ref name=Clements/><ref name=HBW2020/>

==Description==

Male blue-tailed emeralds are {{cvt|7.5|to|9.5|cm|in}} long and females {{cvt|6.5|to|7.5|cm|in}}. Males of ''C. m. caribaeus'' average about {{cvt|2.7|g|oz}} and females about {{cvt|2.5|g|oz}}. Males of ''C. m. phoeopygus'' average about {{cvt|2.7|g|oz}} and females about {{cvt|2.4|g|oz}}. 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.<ref name=BTEM-BOW/>

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.<ref name=BTEM-BOW/>

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 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.<ref name=BTEM-BOW/>

==Distribution and habitat==

The seven subspecies of blue-tailed emerald recognized by the IOC are distributed thus:<ref name=IOC13.2/><ref name=BTEM-BOW/>

* ''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'' forest, and commonly in Ecuador, ''Várzea'' and floodplain forest. In elevation it ranges between {{cvt|750|and|2600|m|ft|sigfig=2}} in Ecuador, up to {{cvt|1200|m|ft|sigfig=2}} in Peru, and from sea level to about {{cvt|1850|m|ft|sigfig=2}} in Venezuela.<ref name=BTEM-BOW/>

==Behavior== ===Movement===

The blue-tailed emerald is mostly sedentary but in some areas apparently makes seasonal movements.<ref name=BTEM-BOW/>

===Feeding===

The blue-tailed emerald forages for nectar mostly by trap-lining, 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 arthropods<ref>{{Cite web |title=Blue-Tailed Emerald |url=https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/documents/ogatt/Chlorostilbon_mellisugus%20-%20Blue-tailed%20Emerald.pdf |website=sta.uwi.edu}}</ref> by hawking from a perch.<ref name=BTEM-BOW/>

thumb|left|A one-week-old blue-tailed emerald in its nest

===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 {{cvt|1|m|ft|sigfig=1}} 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.<ref name=BTEM-BOW/>

{{birdsong|url=https://xeno-canto.org/species/Chlorostilbon-mellisugus |species=blue-tailed emerald}}

===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.<ref name=BTEM-BOW/>

==Status==

The IUCN 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.<ref name=IUCN/> 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.<ref name=BTEM-BOW/>

==References== {{Reflist}}

==Further reading==

*{{cite book | last = ffrench | first = Richard | title = A Guide to the Birds of Trinidad and Tobago | edition = 2nd | year = 1991 | publisher = Comstock Publishing | isbn = 0-8014-9792-2 | ref=none}} *{{cite book | last = Hilty | first = Steven L | title = Birds of Venezuela | publisher = Christopher Helm | year = 2003 | location = London | isbn = 0-7136-6418-5 | ref=none }}

blue-tailed emerald Category:Birds of Colombia Category:Birds of Venezuela Category:Birds of the Guiana Shield Category:Birds of Ecuador Category:Birds of Trinidad and Tobago Category:Birds of the Caribbean Category:Birds of Peruvian Amazonia Category:Birds of the Bolivian Amazon Category:Birds of the Amazon rainforest Category:Hummingbird species of South America blue-tailed emerald blue-tailed emerald Category:Birds of Brazil