The Rondonia bushbird (''Clytoctantes atrogularis'') 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

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

in subfamily Thamnophilinae of family

Thamnophilidae The antbirds are a large passerine bird family, Thamnophilidae, found across subtropical and tropical Central and South America, from Mexico to Argentina. There are more than 230 species, known variously as antshrikes, antwrens, antvireos, fire ...

, the "typical antbirds". 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 Brazil.

Taxonomy and systematics

The Rondonia bushbird was first described to science in 1991 from sightings and a specimen collected in 1986. It was not again recorded away from the type locality until 2005.Costa, T. V. V., C. J. Sharpe, K. Zimmer, M.L. Isler, and G. M. Kirwan (2022). Rondonia Bushbird (''Clytoctantes atrogularis''), version 2.0. In Birds of the World (C. J. Sharpe and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.ronbus1.02 retrieved January 2, 2024 The Rondonia bushbird 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 ...

. It shares genus ''Clytoctantes'' with the

recurve-billed bushbird The recurve-billed bushbird (''Clytoctantes alixii'') is an Endangered species of Thamnophilid antbird that inhabits dense stands of secondary vegetation at the northern end of the Andes in Colombia and Venezuela. It is named for its extraordi ...

(''C. alixii'') and the two are closely related to the black bushbird (''Neoctantes niger'').

Description

The Rondonia bushbird is long and weighs about . It is rather stocky with a short tail. Its large bill is laterally compressed and the

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...

is upturned. The sexes have different plumage. Adult males are mostly dark gray, with a hidden white patch between their shoulders and a slightly blacker bib. Adult females have a chestnut head and upper back, with a concealed white patch like the male's. Their lower back is brown, their 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 ...

gray, and their tail black. Their wing coverts are dark chestnut with paler edges and their flight feathers dark grayish brown with chestnut-brown edges. Their throat, cheeks, and upper breast are black, their lower breast, sides and belly light chestnut, and their flanks and undertail coverts gray. Their iris is brown, their

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

black, their

dark gray to black, and their legs and feet gray. Subadult males are similar to adults but with dusky flight feathers and a scattering of brown feathers on the crown.

Distribution and habitat

The Rondonia bushbird was first described near the Rio Jiparana, a tributary of the

Rio Madeira The Madeira River ( pt, Rio Madeira, link=no ) is a major waterway in South America. It is estimated to be in length, while the Madeira-Mamoré is estimated near or in length depending on the measuring party and their methods. The Madeira is ...

in the Brazilian state of

Rondônia Rondônia () is one of the 26 states of Brazil, located in the northern subdivision of the country (central-western part). To the west is a short border with the state of Acre, to the north is the state of Amazonas, in the east is Mato Grosso, ...

. Since then it has been documented at additional sites between the rios Madeira and Sucunduri to its east in the state of Amazonas, and also in

Mato Grosso Mato Grosso ( – lit. "Thick Bush") is one of the states of Brazil, the third largest by area, located in the Central-West region. The state has 1.66% of the Brazilian population and is responsible for 1.9% of the Brazilian GDP. Neighboring ...

. It primarily inhabits lowland humid ''

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 in locations with tangles of vines, a dense understory, and sometimes with ''

Guadua ''Guadua'' is a Neotropical genus of thorny, clumping bamboo in the grass family, ranging from moderate to very large species. Physically, ''Guadua angustifolia'' is noted for being the largest Neotropical bamboo. The genus is similar to ''Bam ...

'' bamboo. It has also been recorded in moderately disturbed forest and near recently logged areas, and once in campina. In elevation it is known only below .

Behavior

Movement

The Rondonia bushbird is believed to be a year-round resident throughout its range.

Feeding

The Rondonia bushbird feeds on insects, especially ants. It forages in vine tangles and on bamboo; on the latter it uses its bill to slit open the stem. It has also been observed apparently foraging on palm leaves. Most of the sightings have been of single birds or pairs.

Breeding

Nothing is known about the Rondonia bushbird's breeding biology.

Vocalization

The Rondonia bushbird's song is "''tree-tree-tree'', consisting of long sequences of regularly spaced, essentially identical whistled notes" that can be heard beyond . Its calls include " n alarma slightly chattering but relatively steady series of very slightly squeaky notes, and a single-note contact call...in a sequence of seven or eight 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 ...

originally in 1994 assessed the Rondonia bushbird as Data Deficient, then in 2000 as Critically Endangered, in 2008 as Vulnerable, and since 2023 as Near Threatened. It has a small range and its estimated population of 2500 to 10,000 mature individuals is believed to be decreasing. The area around the type locality has been mostly cleared of forest and a hydroelectric dam has flooded much of it. Clearing for agriculture, grazing, and logging continues in other parts of Rondônia, as does dam construction. However, since about 2005 the species has been discovered in other areas. "Systematic survey works in Rondônia, Amazonas and Mato Grosso are urgently needed in order to locate any additional sites where this species may occur."

Notes

References

External links

BirdLife Species Factsheet
{{Taxonbar, from=Q1263952 Rondônia bushbird Birds of the Brazilian Amazon Endemic birds of Brazil Rondônia bushbird Taxonomy articles created by Polbot