Nombre en español: Anambé chico
Nombre en inglés: White-naped Xenopsaris
Nombre científico: Xenopsaris albinucha
Familia: Tityridae
El anambé chico (Xenopsaris albinucha), también denominado tijerilla (en Argentina y Paraguay), xenopsaris de nuca blanca (en Perú), añambé chico (en Uruguay) o jipato de nuca blanca (en Venezuela), es una especie de ave paseriforme de la familia Tityridae, la única del género monotípico Xenopsaris, aunque anteriormente se la ha colocado en Cotingidae o Tyrannidae. Se distribuye en el centro y norte de América del Sur.
Distribución y hábitat
Se distribuye en tres poblaciones reproductoras discontinuas, cada una de las cuales muestra un comportamiento migratorio diferente. La población del norte de Sudamérica es residente y se registra durante todo el año en Venezuela, Guyana y el extremo norte de Brasil. Una población meridional se reproduce en Argentina (en el noroeste, noreste y las provincias del centro, llegando por el sur hasta la ribera austral del Río de la Plata), oeste de Uruguay, Paraguay y el sur de Brasil, principalmente de noviembre a marzo, y luego migra hacia el centro de Brasil y Bolivia de abril a octubre, con algunos individuos, posiblemente errantes, que alcanzan el sureste de Brasil y el sur de Perú. Por último, una población del noreste brasileño se reproduce en los bosques estacionalmente secos —la llamada caatinga— de diciembre a mayo, y migra parcialmente hacia el oeste/suroeste del país durante la estación seca de la región.
Esta especie es considerada poco común y local en sus hábitats naturales: los bosques semiáridos subtropicales o tropicales y bosques húmedos subtropicales o tropicales, siempre en baja altitud. pero hasta los 1100 m en Bolivia.
Descripción
Mide 13 cm de longitud y pesa alrededor de 10g. El macho tiene la corona negra con loruns blancos y nuca gris pálido; por arriba es gris pardacento, más parduzco en las alas; la cola es negruzca, con el contorno externo de las plumas externas blanco. Por abajo es blanco. La hembra tiene la corona más parda, como también las partes superiores y el vientre teñido de amarillento; los juveniles tienen la corona escamada de blanco.
Comportamiento
Es encontrado solitario o en pareja, usualmente no se junta a bandadas mixtas. Es considerada una de las aves más enigmáticas del Neotrópico y su situación permanece poco clara en la mayoría de su rango, con evidencias de nomadismo y alimentación oportunista.
Alimentación
Busca insectos de pequeño porte en el suelo o en ramas bajas.[11]
Reproducción
Construye un nido en forma de taza en los árboles. La nidificación ocurre entre junio y septiembre en Venezuela, con nidos activos en julio e incubación en agosto; en Argentina ocurre entre octubre y enero.
Vocalización
Generalmente es callado. Los machos emiten un silbido fino, de timbre alto, «tsip, tsiwiií, tsii-ti-ti-ti-ti».
Sistemática
Descripción original
Esta especie fue descrita originalmente por el ornitólogo germano – argentino Carlos Germán Burmeister en el año 1869, bajo el nombre científico de: Pachyrhamphus albinucha. La localidad tipo dada es: «Cerca de Buenos Aires, Argentina».
El género Xenopsaris fue propuesto por el ornitólogo estadounidense Robert Ridgway en el año 1891.
Etimología
El nombre genérico femenino «Xenopsaris» es una composición de la palabra del griego «ξενος xenos» que significa ‘extraño’ y del género Psaris, entonces utilizado para los anambés; el nombre de la especie «albinucha», se compone de las palabras del latín «albus» que significa ‘blanco’ y «nuchus» que significa ‘nuca’.
Taxonomía
Sus afinidades taxonómicas son todavía inciertas. Las primeras hipótesis de los especialistas presumían que este género era cercano a Knipolegus, Serpophaga y Suiriri; investigaciones posteriores lo incluyeron en la familia Cotingidae y allí cercana a Pachyramphus. Estudios sistemáticos posteriores indicaron que, sobre la base de un análisis cladístico de su morfología, esta especie puede ser el pariente más cercano de Pachyramphus, pero con afinidades algo inciertas. Se ha sugerido que los dos géneros deberían fusionarse, pero en la mayoría de los tratamientos el género Xenopsaris se mantiene como monotípico debido a las diferencias significativas que lo caracterizan: ausencia de un fuerte dimorfismo sexual, escamación tarsal diferente, distinto tipo de nido, remera primaria P9 corta y en punta, tamaño mucho más pequeño, etc.
Las evidencias más recientes sugieren que el presente género pertenece a un clado basal dentro su familia, incluyendo también los géneros Iodopleura, Tityra y Pachyramphus (con una pobre sustentación por el método de remuestreo estadístico Bootstrapping).
Los amplios estudios genético-moleculares de Tello et al. (2009) y Ohlson et al. (2013) descubrieron una cantidad de relaciones novedosas dentro de los paseriformes subóscinos que todavía no están reflejados en la mayoría de las clasificaciones. Específicamente para la familia Tityridae, corroboraron las tesis anteriores y propusieron la subfamilia Tityrinae Gray, 1840 agrupando a Xenopsaris, Tityra, Iodopleura y Pachyramphus.
Subespecies
Según la clasificación AviList: The Global Avian Checklist se reconocen 2 subespecies, con su correspondiente distribución geográfica:
- Xenopsaris albinucha minor Hellmayr, 1920 – Venezuela, Guyana y el extremo norte de Brasil, en el estado de Roraima.
- Xenopsaris albinucha albinucha (Burmeister, 1869) – noreste y centro de Brasil, Uruguay, Paraguay, Argentina, Bolivia y sur de Perú.
White-naped xenopsaris
The white-naped xenopsaris (Xenopsaris albinucha), also known as the reed becard and white-naped becard, is a species of suboscine bird in the family Tityridae, the only member of the genus Xenopsaris. It is found in South America, in humid subtropical and tropical savanna climates in most of the countries east of the Andes: Venezuela, Brazil, Bolivia, Paraguay, Uruguay, and Argentina. Living in open woodland and other open forest habitats, it is mostly sedentary, though some populations may be migratory. The species, which is closely related to becards and tityras, was thought to be either a tyrant-flycatcher or cotinga, before it was placed in Tityridae.
The bird is 12.5 to 13 cm (4.9–5.1 in) in length, with whitish undersides, a black crown, and grey-brown upperparts. The sexes are similar in appearance, though the females have duller upperparts. It feeds on insects in the foliage of trees and bushes, and sometimes on the ground. Nesting occurs in a simple cup nest placed in the fork of a tree. Both parents incubate the eggs and help feed the chicks. When the chicks fledge, the parents may divide up the brood to continue helping. The species is not common and little is known about it, but it is not considered in danger of extinction, and has been classified as of least concern by the International Union for Conservation of Nature.
Taxonomy and systematics
The white-naped xenopsaris was described in 1869 by the German-Argentine scientist Hermann Burmeister, based on a specimen collected near Buenos Aires. Burmeister originally placed it in the becard genus, Pachyramphus. It was moved to the monotypic genus Xenopsaris by Robert Ridgway in 1891, but was still known to be closely related to Pachyramphus. A 1989 study of anatomy identified Pachyramphus as a sister taxon to Xenopsaris, but the white-naped xenopsaris was kept in its own genus due to several morphological and behavioural differences, namely its smaller size, the shape of its legs, the length of its primary flight feathers, the lack of strong sexual dimorphism (differences between the sexes) and the construction of the nest.
Which family the species belonged to remained unresolved for over a century. According to the Handbook of the Birds of the World, Xenopsaris and its allies were «taxonomically problematic genera that have for more than a hundred years been shifted back and forth between the cotingas (Cotingidae) and the Tyrannidae». When placed with the tyrant-flycatchers, Tyrannidae, it was considered closely related to the genera Suiriri, Serpophaga and Knipolegus. The uncertainty was not confined to this species, as there was a general confusion about where to draw the lines between the cotingas, tyrant-flycatchers and manakins.
Resolution was provided by the same 1989 study that confirmed the link between Xenopsaris and Pachyramphus. In it, Xenopsaris and six other genera previously held in the three families were found to actually form a fourth family, later named Tityridae. This new family is where the genus is now placed by the South American Classification Committee of the American Ornithological Society. A 2007 study of mitochondrial DNA confirmed the white-naped xenopsaris’ place in the Tityridae, and its close relationship to Pachyramphus, as well as the genus Tityra. These three genera were found to be more distantly related to a fourth genus Iodopleura (the purpletufts), although further studies are needed to understand the complete relationship between these four genera.
The genus name Xenopsaris was derived from the Ancient Greek word xeno, meaning «stranger», and Psaris, a synonym for Tityra, based on the Ancient Greek for starling, described by Georges Cuvier in 1817.[7] The specific name albinucha is from Latin and refers to the bird’s white (albus) nape (nuchus)] The species is also known as the reed becard,[2] white-naped becard and simply xenopsaris.
There are two subspecies of white-naped xenopsaris; the widespread nominate subspecies, and the more restricted X. a. minor of Venezuela, which was described by Carl Eduard Hellmayr in 1920.
Description
The white-naped xenopsaris is smaller than the closely related becards and tityras, measuring 12.5 to 13 cm (4.9–5.1 in) in length and weighing around 10 g (0.35 oz). The subspecies X. a. minor has the same plumage as the nominate subspecies, but is smaller; the wing-chord (measurement from the wrist-joint to the end of the wing) length of the nominate subspecies, for example, is 6.4 to 6.6 cm (2.5–2.6 in) compared to 6.0 to 6.2 cm (2.4–2.4 in) in X. a. minor.
The face, lores, throat, breast, belly and rump of this species are white; the undersides are tinged with grey on the chest and yellow on the belly. The crown is glossy black in males. The nape is pale grey with a grey-white to white band separating the crown from the back. The wings are dusky greyish brown with white edging on the inner remiges and wing-coverts. The tail is dusky brown, and the stout bill, iris and legs are black. The female is similar to the male, but is duller overall and has a chestnut-tinged crown. Juvenile birds resemble adults but have greyish napes and more chestnut in the crown, and the feathers of the back, rump and primaries are scalloped with ochre. The secondaries on the wing and the tail feathers are edged with white.
The song of this species is delicate, and does not carry far. It is most commonly heard during the rainy season, but can be heard at any time of the day. The call is described as a thin, high-pitched and hesitant «teep, tre’e’e’e’e’a eea wu’u’u’e’e’e-e-e-e-e-p» or a «twip, tsiweeé, tseee, ti-ti-ti-ti», according to the Handbook of the Birds of the World. The initial trill is described as rising and then falling, and the last trill is described as long. Birds may sometimes vary the pattern and only use part of the song. The species is also described as making a squeaky and undulating screech, and males are described as whistling on the nest. Foraging males have been observed making an ascending «shreee» every few seconds while hunting for insects.
The white-naped xenopsaris looks somewhat similar to the cinereous becard, which overlaps its range in Venezuela. The white-naped xenopsaris is smaller, with a longer tail, thinner bill, whiter underparts (instead of grey) and browner upperparts (rather than greyish).
Distribution and habitat
The white-naped xenopsaris has a disjunct distribution. The southern population of the nominate subspecies is widespread from north-eastern Brazil through to Bolivia, Paraguay and northern Argentina and Uruguay. A separate population of the nominate is found in Guyana. The subspecies X. a. minor is found in west and central Venezuela, and probably extends into north-eastern Colombia.
The species is generally resident across its range, but sightings of solitary and silent birds have suggested that the species may be migratory in Bolivia and Brazil. A study published in 2005 suggested it was migratory in Santa Fe, Argentina, as the species was not observed in the area between March and September (the austral winter). In 2006 the species was reported for the first time in Peru, but it was unclear if this represented a vagrant escaping cold weather or a migrant, as the species is mostly uncommon across its range and that area is poorly studied ornithologically.
They occupy a variety of habitats across their range, including Caatinga scrubland, riparian (river) woodland, lightly wooded areas, the borders of open gallery forest and open areas with scattered trees. They usually live near water or damp areas, and range from sea-level to 550 m (1,800 ft).
Behaviour
Diet and feeding
The white-naped xenopsaris feeds on insects, but no studies have yet been done on the diet of adults. Chicks in the nest are fed grasshoppers from the family Acrididae, mantidflies, praying mantises and mosquitoes. Adults typically hunt singly or sometimes in pairs, and breeding pairs can often be observed hunting well apart from each other. They are shy, generally quiet and inconspicuous. They typically hunt from a perch on the outer edge of the foliage of trees, watching for prey and then launching themselves 0.5 to 1.5 m (1.6–4.9 ft) to snatch prey off leaves. They also strike from a hovering position above foliage, and may chase prey acrobatically for some distance. They often feed near the ground and sometimes take prey from the ground as well as from vegetation.
Breeding
The species is territorial, with the males defending the territory. Nesting timing varies by location; in Venezuela it is reported to occur during the rainy season (June to September), and in Argentina during the austral summer (October to January). The nests are cup-shaped, 4.5 cm (1.8 in) across, 4 cm (1.6 in) high and 1.8 cm (0.71 in) deep. Nests have been recorded being constructed from fine dry grass, or woven plant fibre and a few rootlets. Nests are placed in the forks of branches 4 to 15 m (13–49 ft) up in trees 15 to 20 m (49–66 ft) tall. The clutch size is three eggs, which are greenish with brown spots. Both sexes incubate the eggs during the 14–15 day brooding period. The species has been described as very tame during this interval – staying on the nest even as researchers came within a few centimetres of the bird – but were very aggressive in attacking birds, like guira cuckoos, or other animals that came near the nest. The hatchlings are dark-skinned with grey down and pink mouths. Pink mouths in chicks are very unusual in suboscines.
Chicks hatch within 24 hours of each other. Six days after hatching, the chicks’ eyes have opened and after eight days they are covered in whitish down. Chicks defecate outside of the nest by raising their tail to the side of the nest, so nests with older chicks are surrounded by faecal matter. Both parents feed and brood the chicks, taking it in turns. When one parent returns with food, it takes over brooding duties while the other leaves to hunt.
The chicks are fed by the parents for several days after fledging. The family may travel as a group or the parents may divide the brood, taking one or two chicks each.
Conservation status
Across its range, the white-naped xenopsaris is uncommon and patchily distributed. It has not been evaluated as threatened by the IUCN Red List, as it does not meet any of the criteria. The population is evaluated as being stable, as there is no evidence of any decline or extreme fluctuations. It also occupies an enormous range, estimated to be 11 million km2 (4.2 million sq mi). For these reasons, it is evaluated as a species of least concern.
Fuente: Wikipedia/eBird/xeno-canto