The olivaceous thornbill (''Chalcostigma olivaceum'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

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 "coquettes", tribe

Lesbiini Lesbiini is one of the two tribes that make up the subfamily Lesbiinae in the hummingbird family Trochilidae. The other tribe is Heliantheini (brilliants). The informal name "coquettes" has been proposed for this group as the largest genus, ''L ...

of subfamily

Lesbiinae Lesbiinae is one of the six subfamily, subfamilies that make up the hummingbird family (biology), family Trochilidae. The subfamily is divided into two Tribe (biology), tribes: Heliantheini ("brilliants") containing 14 genera and Lesbiini ("coqu ...

. It is found in

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

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

.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 taxonomy of genus ''Chalcostigma'' is unsettled. The South American Classification Committee (SACC) of the

American Ornithological Society The American Ornithological Society (AOS) is an ornithological organization based in the United States. The society was formed in October 2016 by the merger of the American Ornithologists' Union (AOU) and the Cooper Ornithological Society. Its m ...

is considering a proposal to merge the genus into '' Oxypogon''. The olivaceous thornbill has two subspecies, the nominate ''C. o. olivaceum'' and ''C. o. pallens''.

Description

The olivaceous thornbill is long. One male specimen weighed and a female one . Both sexes have a short black bill. Adult males of the nominate subspecies are mostly dull dark bronzy or olive green, including the tail. The face and throat are dark sooty gray. It has a narrow

gorget A gorget , from the French ' meaning throat, was a band of linen wrapped around a woman's neck and head in the medieval period or the lower part of a simple chaperon hood. The term later described a steel or leather collar to protect the thro ...

that is glittering green at the throat and shades through yellow, pink, and purple to blue at its bottom. The adult nominate female is essentially the same but the gorget is much smaller or may be absent. Juveniles have tan margins on some feathers; males' throats are gray brown and females' gray brown with pale margins. ''C. o. pallens'' is similar to the nominate but smaller and overall paler. The upperparts have a grayish cast to the bronzy or olive green, the tail is bronzy olive brown, and the underparts are dark sooty brown.Schulenberg, T. S. and C. W. Sedgwick (2020). Olivaceous Thornbill (''Chalcostigma olivaceum''), 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.olitho1.01 retrieved February 24, 2022

Distribution and habitat

The nominate subspecies of olivaceous thornbill is found from Apurímac in southeastern Peru to Bolivia's La Paz Department. Its distribution is nearly continuous along this axis. ''C. o. pallens'' is found on the western slope of the Peruvian

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 ...

between the departments of

Ancash Ancash ( qu, Anqash; es, Áncash ) is a department and region in northern Peru. It is bordered by the departments of La Libertad on the north, Huánuco and Pasco on the east, Lima on the south, and the Pacific Ocean on the west. Its capital i ...

and Junín. Its distribution is more patchy, with records only at scattered sites. In elevation the species ranges between in Peru and in Bolivia. The species is most often found in somewhat humid

puna grassland The puna grassland ecoregion, of the montane grasslands and shrublands biome, is found in the central Andes Mountains of South America. It is considered one of the eight Natural Regions in Peru,Pulgar Vidal, Javier: Geografía del Perú; Las Ocho ...

s but also inhabits low scrub and the edges of dense woods of ''

Polylepis ''Polylepis'' is a genus comprising 28 recognised shrub and tree species, that are endemic to the mid- and high-elevation regions of the tropical Andes. This group is unique in the rose family in that it is predominantly wind-pollinated. They are ...

'' and ''

Gynoxys ''Gynoxys'' is a genus of South American flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('cont ...

''.

Behavior

Movement

The olivaceous thornbill is resident throughout its range.

Feeding

The olivaceous thornbill feeds on both nectar and insects. Details of its diet are lacking but there is some evidence that insects predominate. It forages near the ground and has even been observed walking on matted grass. It captures small insects by sallying from the ground or by gleaning from low vegetation. Males defend feeding territories.

Breeding

The olivaceous thornbill'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 not well understood. Its breeding season appears to include January but its span is not known. It possibly nests in ''Polylepis''/''Gynoxys'' woods. As is typical of hummingbirds, the female alone incubates the clutch of two eggs.

Vocalization

As of early 2022, Xeno-c anto had only one recording of an olivaceous thornbill vocalization, described as "a 'tzit' call". Cornell University's

Macaulay Library The Macaulay Library is the world's largest archive of animal sounds. It includes more than 33 million photographs, 1.2 million audio recordings, and over two hundred thousand videos covering 96 percent of the world's bird species. There are an ever ...

had 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 ...

has assessed the olivaceous thornbill as being of Least Concern. It has a large range but its population size is unknown and believed to be decreasing. It is described as rare to uncommon in different parts of its range. "Human activity has little short-term direct effect on Olivaceous Thornbill"

References

{{Taxonbar, from=Q569140 olivaceous thornbill Birds of the Peruvian Andes Birds of the Bolivian Andes olivaceous thornbill Taxonomy articles created by Polbot