The grey-tailed mountaingem (''Lampornis cinereicauda''), also variously spelled gray-tailed mountaingem, grey-tailed mountain-gem, or gray-tailed mountain-gem, 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 tribe Lampornithini of subfamily Trochilinae. It is endemic to

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 ...

.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 grey-tailed mountaingem is treated as a species by the International Ornithological Committee (IOC) 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). However, the North American Classification Committee of the American Ornithological Society 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 ...

treat it as a subspecies of the white-throated mountaingem (''Lampornis castaneoventris'').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 25 August 2021

Description

The grey-tailed mountaingem is about long and weighs about . It has a medium-length straight black bill, dark cheeks, and a white stripe behind the eye. Males have mostly dark bronzy green upperparts with an emerald green crown and a gray tail. Their chin and throat are white, the sides of the neck and upper breast bright green, and the lower breast and vent area dark gray. Females have entirely bright green upperparts and a gray tail. Their throat and belly are dark rufous and the 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 ...

are gray with white or buff edges.Juárez-Jovel, R. C. (2020). White-throated Mountain-gem (''Lampornis castaneoventris''), 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.wtmgem1.01 retrieved 26 May 2022

Distribution and habitat

The grey-tailed mountaingem is found only in the

Cordillera de Talamanca The Cordillera de Talamanca is a mountain range that lies in the southeast half of Costa Rica and the far west of Panama. Much of the range and the area around it is included in La Amistad International Park, which also is shared between the two ...

of southern Costa Rica. It inhabits the interior, edges, and shrubby clearings of oak forest and also gardens in communities near the forest. In elevation it ranges from up to timberline.

Behavior

Movement

The grey-tailed mountaingem moves to the lower part of its elevation range after breeding.

Feeding

The grey-tailed mountaingem feeds on nectar from a variety of flowering plants. Males typically feed at

epiphyte An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...

s in the forest interior while females more often feed in shrubby areas. Males are territorial, defending flower patches. They are dominant over smaller hummingbirds and subordinate to larger ones like the fiery-throated hummingbird (''Panterpe insignis''). The species also feeds on small arthropods gleaned from foliage.

Breeding

The grey-tailed mountaingem's breeding season spans from October to April. Its nest has not been described but is believed to be similar to that of its close relative the white-throated mountaingem ''sensu stricto''. That nest is a cup of fine fibers with moss and some lichen on the outside. The incubation length and time to fledging are not known.

Vocalization

The grey-tailed mountaingem makes high pitched calls described as "''ziit'' or ''ziip''" and also "a 'sputtery, bubbly' song".

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 grey-tailed mountaingem as being of Least Concern, though it has a small range and its population size and trend are unknown. It is considered fairly common in the right habitat. However, "this hummingbird is potentially threatened by human activities" such as deforestation for timber and agriculture.