The white-tailed hummingbird (''Eupherusa poliocerca'') is a

Near Threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...

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

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to southwestern

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

.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 hummingbird 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 ...

. However, in the past some authors have treated the Oaxaca hummingbird (''E. cyanophrys'') as a subspecies of it. Others have treated the white-tailed as a subspecies of the stripe-tailed hummingbird (''E. eximia'').Arizmendi, M. d. C., C. I. Rodríguez-Flores, C. A. Soberanes-González, and T. S. Schulenberg (2020). White-tailed Hummingbird (''Eupherusa poliocerca''), version 1.0. In Birds of the World (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.whthum1.01 retrieved September 1, 2022

Description

The white-tailed hummingbird is long and weighs . Both sexes have a straight black bill. Males have bright metallic bronze green upperparts. Rufous

primaries Primary elections, or direct primary are a voting process by which voters can indicate their preference for their party's candidate, or a candidate in general, in an upcoming general election, local election, or by-election. Depending on the c ...

and secondaries show as a patch on the folded wing. Their central pair of tail feathers are metallic bronze green and the other four pairs grayish white. Their underparts are bright metallic yellowish green with white undertail

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 ...

. Females have bright metallic golden green upperparts with a similar wing "patch" as the male's. Their central tail feathers are metallic golden green and the others white with some dusky or bronze green. Their underparts are grayish white with metallic green spots on the side and white to grayish white undertail coverts.

Distribution and habitat

The white-tailed hummingbird is found on the Pacific slope of the southwestern Mexican state of Guerrero and slightly into western

Oaxaca Oaxaca ( , also , , from nci, Huāxyacac ), officially the Free and Sovereign State of Oaxaca ( es, Estado Libre y Soberano de Oaxaca), is one of the 32 states that compose the political divisions of Mexico, Federative Entities of Mexico. It is ...

. It inhabits the edges and interior of humid montane, semi-deciduous, and pine-oak forest, and plantations. It apparently requires intact forest and is not found in shade coffee plantations. In elevation it ranges between .

Behavior

Movement

The white-tailed hummingbird's movements are not well known, but it might make seasonal elevational changes.

Feeding

The white-tailed hummingbird forages for nectar at all levels of the forest from the understory to the canopy. Its diet has not been described in detail but it is known to feed at flowers of '' Inga'', '' Lobelia'', '' Malvaviscus'', and ''

Psittacanthus ''Psittacanthus'', also parrot-flower, is a plant genus in the family Loranthaceae. It is a type of mistletoe native from central Mexico southwards to Central America and parts of South America.Vázquez Collazo, I. & Geils, B.W. 2002. It differ ...

'' and some others. It is also assumed to feed on 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 like other hummingbirds.

Breeding

The white-tailed hummingbird's 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 ...

is scarcely known. The timing of specimens in breeding condition suggest two breeding peaks, February to May and September to October. Its nest has not been described.

Vocalization

The white-tailed hummingbird's song has been described as "a high, rapid, slightly liquid to squeaky warbling". One call is "a liquid to slightly buzzy, rolled chip, often run into rattled trills". As of mid-2022 the Cornell Lab of Ornithology's Macaulay Library has very few recordings and

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 ...

has none.

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 ...

originally assessed the white-tailed hummingbird as Threatened, then in 1994 as Endangered, in 2000 as Vulnerable, and since 2021 as Near Threatened. It occurs patchily in its small range. Its estimated population of fewer than 15,000 mature individuals is believed to be decreasing. Some forest in its range has been destroyed and much of the rest is under threat of logging or clearing for agriculture. Mexican authorities consider it threatened.

References

External links

BirdLife Species Factsheet
{{Taxonbar, from=Q1274709 white-tailed hummingbird Birds of Mexico Endemic birds of Southern Mexico white-tailed hummingbird Taxonomy articles created by Polbot Birds of the Sierra Madre del Sur