Sabanero Zumbador/Yellow-browed Sparrow/Ammodramus aurifrons

Nombre en español: Sabanero Zumbador

Nombre en ingles: Yellow-browed Sparrow

Nombre científico: Ammodramus aurifrons

Familia: Emberizidae

Canto: Andrew Spencer

El chingolo cejigualdo (Ammodramus aurifrons), también denominado sabanero de cejas amarillas, sabanero zumbador (Colombia), sabanero cejiamarillo (Ecuador) o sabanerito frentiamarillo (Venezuela), es una especie de ave paseriforme perteneciente al género Ammodramus que integra la familia Passerellidae. Es nativo de América del Sur.

Descripción

Mide 13 cm. Por arriba es pardo grisáceo estriado de oscuro, con amarillo notable en el rostro y frente (especialmente en el lorum y supercilio). Curva del ala también amarilla. Por abajo es gris pálido. Es bastante parecido con el chingolo pajonalero (Ammodramus humeralis) con quien puede ser sintópico en algunas regiones. Este chingolo tiene cola corta, pero con piernas desproporcionadamente largas y grandes, y un pico prominente bastante largo; no exhibe el mismo visual cabezón de A. humeralis.

Distribución y hábitat

Se encuentra en Bolivia, Brasil, Colombia, Ecuador, Perú y Venezuela.
Habita en pastizales y sabanas secos y estacionalmente húmedos o inundables, tropicales y subtropicales; y subtropicales de altitud. En áreas de pastos de la Amazonia extendiéndose al norte a lo largo del Río Orinoco hasta los 1300 msnm en las faldas orientales de los Andes.

Comportamiento

Este pájaro familiar ocurre alrededor de pueblos y ciudades, a lo largo de caminos y en áreas de agricultura; su hábitat original fue, aparentemente, a lo largo de ríos y en islas fluviales.
Actualmente presenta una explosión populacional, desde que se beneficia de la deforestación en la cuenca amazónica. Una vez que el bosque es talado y viene la agricultura, o los pastizales crescen en lugar de árboles, este chingolo ocupa el lugar. Diferente de A. humeralis que requiere pastizales antiguos o áreas menos perturbadas, parece que para esta especie, cuanto más perturbado, mejor.

Alimentación

Busca y se alimenta en el suelo, también con frecuencia encaramado en cercas y en lo alto de matorrales; usualmente no se asocia con otros pájaros.

Vocalización

El canto, dado a lo largo del día, es un zumbido distinto “tic, tzzzz-tzzzz”. También emite un rápido “tsiu tsiu tsi tsi tsi”.

Sistemática

Descripción original

La especie A. aurifrons fue descrita por primera vez por el naturalista alemán Johann Baptist von Spix en 1825 bajo el nombre científico Tanagra aurifrons; localidad tipo errada «provincia Bahía» enmendado para «Fonte Bõa, Río Solimões, Brasil».

Taxonomía

Anteriormente colocado, junto con Ammodramus humeralis en un género separado, Myospiza, fueron reasignadas a Ammodramus (siguiendo a Paynter 1970; Klicka & Spellman 2007, SACC). Ambas fueron alguna vez consideradas como formando una superespecie, pero las zonas se sobreponen lo suficiente como para hacer tal tratamiento implausible. Los estudios genéticos indican que ambas son parientes cercanas de Ammodramus savannarum, que, por su vez, es distante de las otras seis especies actualmente incluidas en el género; estas últimas tal vez deberían ser reasignadas a un género diferente.

Subespecies

De acuerdo a las clasificaciones Clements Checklist 6.9 y el Congreso Ornitológico Internacional (IOC) Versión 4.3 -2014, se reconocen 4 subespecies con su correspondiente distribución geográfica:

Ammodramus aurifrons apurensis (Phelps, Sr & Gilliard, 1941) – noreste de Colombia al este a través de los llanos del oeste de Venezuela hasta el delta del Río Orinoco.
Ammodramus aurifrons cherriei (Chapman, 1914) – centro este de Colombia (en los llanos de Meta).
Ammodramus aurifrons tenebrosus (J. T. Zimmer & Phelps, Sr, 1949) – suroeste de Venezuela (suroeste de Amazonas), sureste de Colombia (Guainía y este de Vaupés) y adyacencias del oeste de Brasil.
Ammodramus aurifrons aurifrons (Spix, 1825) – sureste de Colombia (sureste de los Andes) al sur a través del este de Ecuador y este del Perú hasta el noreste de Bolivia, y al este a través de la Amazonia brasileña.

Yellow-browed sparrow

The yellow-browed sparrow (Ammodramus aurifrons) is a species of bird in the family Passerellidae. First described by Johann Baptist von Spix in 1825, this American sparrow is found across much of the Amazon basin in South America. Its natural habitats are subtropical or tropical moist shrubland, pastureland, and heavily degraded former forest.

Taxonomy

When Johann Baptist von Spix first described the yellow-browed sparrow in 1825, he put it in the now-defunct genus Tanagra, believing it to be a tanager. The classification error was soon recognized, and the species was moved first to the genus Ammodramus, then to Myospiza—a genus Robert Ridgway created in 1898 for this and the closely related grassland sparrow.^[3] Most taxonomists now subsume Myospiza into Ammodramus. DNA analysis indicates that the yellow-browed sparrow is a sister species to the grassland sparrow, and that these two species make a sister group with the grasshopper sparrow; these three are genetically distinct from the other Ammodramus sparrows. The yellow-browed sparrow has four subspecies, which differ primarily in the extent of yellow on the face and the amount of streaking on the upperparts and crown:

A. a. apurensis, first described by William Henry Phelps and Ernest Thomas Gilliard in 1941, is found in northeastern Colombia.
A. a. cherriei, first described by Frank Chapman in 1914, is found in central Colombia.
A. a. tenebrosus, first described by John Todd Zimmer and Phelps in 1949, ranges from southeastern Colombia through southwestern Venezuela into the adjacent areas of Brazil.
A. a. aurifrons, described by Spix in 1825, ranges south from southeastern Colombia into central Bolivia and east along the Amazon basin to the Atlantic coast.

The yellow-browed sparrow is one of nine sparrows in the genus Ammodramus, a name which means «desert runner» or «desert racer» (from the Greek ammos, meaning «desert» and -dromos, meaning «-racer» or «-runner»). The species name aurifrons is a combination of the Latin words auri, meaning «gold» and frons, meaning «forehead» or «front».

Description

The yellow-browed sparrow is a small American sparrow, measuring 13 cm (5 in) in length, with a mass between 14.5 and 19 g (0.5 and 0.7 oz). Sexes are similarly plumaged, though males average very slightly larger than females. The adult is brownish gray on the upperparts, with dusky streaks on the back. Its underparts are whitish, shading to grayish on the chest and buff on the flanks. Its legs are pinkish-brown, while the beak is horn-colored, with a darker culmen. Its iris is reddish brown. The juvenile, which has no yellow on its face or wings, is buffier than adults are, with thin brownish streaks on its breast and flanks.

Similar species

Although quite similar to the grassland sparrow, the yellow-browed sparrow typically shows more yellow on its face. It is overall paler and less streaked than the grassland sparrow, and lacks chestnut edges to its flight feathers. It is best told by its buzzy song, its less secretive behavior and less restrictive habitat preferences.

Habitat and range

Although its former habitat was largely along rivers and on islands, the yellow-browed sparrow is now widespread in grassy areas of the Amazon biome, including agricultural fields, roadsides and around towns. It is generally found in the lowlands, though it has been recorded to 1,000 m (3,281 ft) on the east side of the Andes, and regularly as high as 1,500 m (4,921 ft) — and sometimes to 2,000 m (6,562 ft) — in Ecuador.

Behavior

The yellow-browed sparrow is generally easier to see than its sister species is. It is less secretive, and is found in a wider range of grasslands.

Food and feeding

Like most American sparrows, the yellow-browed sparrow is largely granivorous, feeding on the seeds of native grasses and various introduced plants. It also eats insects, including larvae. It typically feeds on the ground.

Breeding

Breeding has been recorded between February and September. The yellow-browed sparrow builds a cup nest of dried grass lined with fine plant material. The nest is generally on the ground in a grass clump, though sometimes it is placed low in a shrub. The female lays 2–3 white eggs.

Voice

The yellow-browed sparrow’s high-pitched song is described as «insect-like». Monotonous and buzzy, it is transcribed as tic, tzzz-tzzzzz, with the first note weak and short. The male sings throughout the day from a low, exposed perch.

Conservation and threats

Because of its very large range and apparently stable population, the yellow-browed sparrow has been designated by the International Union for the Conservation of Nature (IUCN) as a species of least concern. It is described as common throughout its range, though its numbers have not been quantified. This species has benefited from the clearing of rainforest for agriculture and cattle ranching; it is common in early successional fields.

In South America, the Yellow-browed Sparrow is the tropical grassland replacement of the Grassland Sparrow (Ammodramus humeralis). The Yellow-browed Sparrow does well in much more coarse grassland, in hot lowland areas in the tropics. It is currently showing a major population boom as it is benefiting from forest clearing in the Amazon basin. Once the forest is cleared and agriculture comes in, or rank grass grows up instead of trees, this sparrow moves in. Unlike the Grassland Sparrow which requires older grasslands and less disturbed areas, it appears that the more disturbed the better for the Yellow-browed Sparrow. This sparrow is a short-tailed sparrow, but with oversize long and large legs, and usually a rather prominent long bill; it does not have the same large-headed look of the Grassland Sparrow. More than yellow-browed, this sparrow is yellow faced as the yellow of the supra-lores typically bleeds out to much of the fore face. The upperparts of this sparrow are only obscurely streaked, making it look much more solid in coloration above than is typical for an open country sparrow. Its underparts are pale grayish, and the brown wings show an obvious yellow bend, and sometimes this extends as a yellow shoulder patch.