The curve-billed reedhaunter (''Limnornis curvirostris'') is a species of bird in the Furnariinae subfamily of the ovenbird

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Furnariidae. It is found in

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, and

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

Taxonomy and systematics

The curve-billed reedhaunter and the superficially similar straight-billed reedhaunter (''Limnoctites rectirostris'') were long thought to be closely related; some authors merged ''Limnoctites'' into ''Limnornis''. Genetic studies in the early 2000s refuted this approach by finding that the two species of genus ''Limnoctites'' were instead closely related to the spinetails of genus '' Cranioleuca''.Derryberry, E.P., S. Claramunt, G. Derryberry, R.T. Chesser, J. Cracraft, A. Aleixo, J. Pérez-Emán, J.V. Remsen, Jr., and R. T. Brumfield. 2011. Lineage diversification and morphological evolution in a large-scale continental radiation: the Neotropical ovenbirds and woodcreepers (Aves: Furnariidae). Evolution 65: 2973–2986. The curve-billed reedhaunter is instead most closely related to the wren-like rushbird (''Phleocryptes melanops''). A high resolution version of the phylogenetic tree in Figure 1 is available from the first author's websit
here
The curve-billed reedhaunter is the only member of its genus and has no subspecies.

Description

The curve-billed reedhaunter is long and weighs . It is a small furnariid whose plumage closely resembles that of some

Old World The "Old World" () is a term for Afro-Eurasia coined by Europeans after 1493, when they became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia in the Eastern Hemisphere, previously ...

reed warblers of genus '' Acrocephalus''. It has a long and quite decurved bill. The sexes' plumages are alike. Adults have a whitish

supercilium The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head.Dunn and Alderfer (2006), p. 10 Also k ...

, an ill-defined dark brown band behind the eye, lighter brown ear coverts with some thin whitish streaks, and a whitish malar area. Their crown, nape, back, rump, and uppertail coverts are rich brown; the brown is darkest on the crown and gradually becomes more rufescent to the uppertail coverts. Their wings and tail are rufescent brown. Their throat is whitish, their breast more buffy, their belly creamy buff, their flanks cinnamon-buff, and their undertail coverts a rich buff. Their iris is brown, their

maxilla In vertebrates, the maxilla (: maxillae ) 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 two maxil ...

brown to blackish, their

mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

a whitish and brownish mix, and their legs and feet grayish.Remsen, Jr., J. V. (2020). Curve-billed Reedhaunter (''Limnornis curvirostris''), 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.cubree1.01 retrieved August 24, 2023

Distribution and habitat

The curve-billed reedhaunter is found in the Brazilian state of

Rio Grande do Sul Rio Grande do Sul (, ; ; "Great River of the South") is a Federative units of Brazil, state in the South Region, Brazil, southern region of Brazil. It is the Federative units of Brazil#List, fifth-most populous state and the List of Brazilian s ...

, in southern Uruguay, and in eastern Argentina's Entre Ríos and

Buenos Aires Buenos Aires, controlled by the government of the Autonomous City of Buenos Aires, is the Capital city, capital and largest city of Argentina. It is located on the southwest of the Río de la Plata. Buenos Aires is classified as an Alpha− glob ...

provinces. It primarily inhabits freshwater marshes and also occurs in brackish ones such as coastal lagoons. Their vegetation is often dominated by the sedge ''

Scirpus ''Scirpus'' is a genus of grass-like species in the sedge family Cyperaceae many with the common names club-rush, wood club-rush or bulrush. They mostly inhabit wetlands and damp locations. Description ''Scirpus'' are rhizomatous perennial herbs ...

giganteus'' and the grass '' Zizaniopsis bonarinsis''. It is essentially coastal, with an elevation range from sea level to only about .

Behavior

Movement

The curve-billed reedhaunter is a year-round resident throughout its range.

Feeding

The curve-billed reedhaunter feeds on a variety of adult and larval

arthropod Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

s that it gleans from marsh vegetation. It usually forages by itself.

Breeding

The curve-billed reedhaunter is assumed to breed during the austral spring and summer, and is thought to be monogamous. It constructs a ball-shaped nest of grass, leaves, and other fibers and lines it with softer plant material. The nest has a side entrance, usually with an overhanging "awning". It attaches the nest to reeds or atop vegetation. The clutch size is two eggs. The incubation period, time to fledging, and details of parental care are not known.

Vocalization

The curve-billed reedhaunter's song is a "fast series of harsh notes that ascend and then descend in pitch, fading towards heend". Its call is "a hollow 'took' ".

Status

The

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

originally assessed the curve-billed reedhaunter as Near Threatened, but since 2004 has classed it as being of Least Concern. It has a limited range and an unknown population size that is believed to be stable. No immediate threats have been identified. It is thought to be uncommon. It occurs in several protected areas but its " rrow habitat requirements appear to render it potentially vulnerable".