The chestnut-headed nunlet (''Nonnula amaurocephala'') is a species of

near-passerine Near passerines and higher land-bird assemblage are terms of traditional, pre-cladistic taxonomy that have often been given to tree-dwelling birds or those most often believed to be related to the true passerines (order Passeriformes) owing to mor ...

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 the family Bucconidae, the puffbirds, nunlets, and nunbirds. 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 ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Taxonomy and systematics

The chestnut-headed nunlet 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, the rufous-capped nunlet (''N. ruficapilla''), and the

grey-cheeked nunlet The grey-cheeked nunlet (''Nonnula frontalis'') is a species of near-passerine bird in the family Bucconidae, the puffbirds, nunlets, and nunbirds. It is found in Colombia and Panama. Taxonomy and systematics The grey-cheeked nunlet was firs ...

(''N. frontalis'') form a superspecies.Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, A. Jaramillo, D. F. Lane, J. F. Pacheco, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 24 August 2021. A classification of the bird species of South America. American Ornithological Society. https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm retrieved August 24, 2021Rasmussen, P. C. and N. Collar (2020). Chestnut-headed Nunlet (''Nonnula amaurocephala''), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.chhnun1.01 retrieved November 11, 2021

Description

The chestnut-headed nunlet is long and weighs . Its entire head, upper mantle, breast, and upper belly are bright rufous. Its back, wings, and tail are plain dull brown; the rump has an olive wash. The rufous upper belly grades to whitish on the lower belly. The bill is mostly black, the eye red, and the feet lead gray.

Distribution and habitat

The chestnut-headed nunlet is found only in a small part of Brazil's Amazonas state, north of the

Amazon River The Amazon River (, ; es, Río Amazonas, pt, Rio Amazonas) in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile. The headwaters of t ...

and west of the

Negro River Río Negro (Spanish and Portuguese, 'Black River') may refer to: Rivers Brazil * Rio Negro (Amazon), tributary of the Amazon River * Rio Negro (Mato Grosso do Sul) * Rio Negro (Paraná) * Rio Negro (Rio de Janeiro) * Rio Negro (Rondônia) * ...

. It almost exclusively inhabits the understory of seasonally flooded ''

igapó Igapó (, from Old Tupi: "root forest") is a word used in Brazil for blackwater-flooded forests in the Amazon biome. These forests and similar swamp forests are seasonally inundated with freshwater. They typically occur along the lower reaches of ...

'' forest, usually up to about above the ground but sometimes as high as .

Behavior

Feeding

The chestnut-headed nunlet has been observed sallying from a perch, presumably to catch invertebrate prey, but no details of its feeding behavior or diet have been published.

Breeding

No details of the chestnut-headed nunlet'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 ...

have been published.

Vocalization

No recordings or description of the chestnut-headed nunlet's vocalizations are available as of late 2021.

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 chestnut-headed nunlet in 1988 as Near Threatened but since 2004 has rated it as being of

Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

. It has a very small range and unquantified population that is believed to be decreasing. Its ''igapó'' habitat is widespread and under little human pressure, and the species is probably undercounted due to its quiet and sedentary nature.

References

{{Taxonbar, from=Q1270689 Nonnula Birds of the Amazon Basin Endemic birds of Brazil Birds described in 1921 Taxonomy articles created by Polbot