Nombre en español: Trepatroncos Barbiblanco

Nombre en inglés: White-chinned Woodcreeper

Nombre científico: Dendrocincla merula

Familia: Furnariidae

El trepatroncos barbiblanco (en Colombia y Ecuador) (Dendrocincla merula), también denominado trepador barbiblanco (en Venezuela), trepador de barbilla blanca (en Perú) o trepatroncos de barba blanca,​ es una especie de ave paseriforme de la familia Furnariidae, de la subfamilia Dendrocolaptinae, perteneciente al género Dendrocincla. Es nativa de la cuenca amazónica y del escudo guayanés en América del Sur.

Distribución y hábitat

Se distribuye desde el sur y este de Colombia, hacia el este por el sur y sureste de Venezuela, Guyana, Surinam y Guayana francesa, hacia el sur por el este de Ecuador, este de Perú, por toda la Amazonia brasileña, hasta el centro norte de Bolivia.

​En Colombia se encuentra por debajo de 500 m de altura sobre el nivel del mar al este de los Andes desde el sur del departamento del Meta y el este del departamento de Vichada hacia el sur del país.

Esta especie es considerada poco común en su hábitat natural: el sotobosque de selvas húmedas, tanto de terra firme como de várzea, por debajo de los 500 metros de altitud.​

Descripción

Mide entre 16 y 21 cm de longitud y pesa entre 28 y 57 g.​ El plumaje es de color marrón, sin rayas, excepto una estrecha mancha blanca en la garganta. El iris es gris azulado.​

Alimentación

Se alimenta de insectos y otros artrópodos. Sigue las legiones de hormigas guerreras, para capturar a las presas que tratan de escapar de las hormigas.​

Sistemática

Descripción original

La especie D. merula fue descrita por primera vez por el naturalista alemán Martin Lichtenstein en 1820 bajo el nombre científico Dendrocolaptes merula; su localidad tipo es: «Cayena».​

Etimología

El nombre genérico femenino «Dendrocincla» se compone de las palabras del griego «δενδρον dendron: árbol, y del latín cinclus: tordo, zorzal, que proviene del griego «κιγκλος kinklos»: ave no identificada;​ y el nombre de la especie «merula», proviene del latín y significa «pájaro negro».​

Taxonomía

La presente puede consistir de más de una especie.​ Las subespecies al oeste del río Negro junto a las sureñas al río Amazonas pueden ser una especie separada, con base en diferencias de vocalización, tamaño y color del iris; son necesarios más estudios.​

Subespecies

Según las clasificaciones del Congreso Ornitológico Internacional (IOC)​ y Clements Checklist/eBird v.2019​ se reconocen siete subespecies, con su correspondiente distribución geográfica:​

• Dendrocincla merula merula (Lichtenstein, 1820) – las Guayanas y adyacente norte de Brasil (al este del río Branco en Roraima y norte de Pará).
• Dendrocincla merula obidensis Todd, 1948 – Amazonia brasileña a lo largo de la margen norte del río Amazonas, desde el Negro al este hasta Amapá.
• Dendrocincla merula bartletti Chubb, 1919 – Amazonia occidental y alta cuenca del río Orinoco tanto al norte como al sur del río Solimões, desde el centro de Venezuela y centro de Colombia al sur hasta el este de Ecuador, este de Perú, norte de Bolivia y oeste de la Amazonia brasileña (hacia el este hasta el Negro y el Madeira).
• Dendrocincla merula remota Todd, 1925 – oriente de la Amazonia boliviana (norte de Santa Cruz), probablemente también en las adyacencias de Brasil (borde noroeste del Pantanal).
• Dendrocincla merula olivascens J.T. Zimmer, 1934 – sur de la Amazonia brasileña al sur del Amazonas, desde el Madeira al este hasta el Tapajós.
• Dendrocincla merula castanoptera Ridgway, 1888 – sur de la Amazonia brasileña al sur del Amazonas, desde el Tapajós hasta el Tocantins.
• Dendrocincla merula badia J.T. Zimmer, 1934 – sureste de la Amazonia brasileña desde el Tocantins al este hasta Maranhão.

White-chinned woodcreeper

The white-chinned woodcreeper (Dendrocincla merula) is a species of bird in the Dendrocolaptinae subfamily. It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela. Its natural habitat is subtropical or tropical moist lowland forests.

Seven subspecies of the exclusively Amazonian White-chinned Woodcreeper are generally recognized, but it seems plausible that the nominate subspecies and D. m. obidensis, which are both restricted to areas north of the Amazon and east of the Rio Negro, are better treated as a species apart, based on differences in their songs, size, and eye color. Over its wide range, from southern Venezuela south to northeastern Bolivia, this woodcreeper inhabits a variety of forest types, but it is principally found in terra firme and floodplain regions, and is only usually observed at the fringes of seasonally flooded forests. This obligate follower of army ant swarms, which takes most of its vertebrate and invertebrate prey on or close to the ground, appears to be uncommon over the vast majority of Amazonia, perhaps as a result of it being out-competed by many of the larger ‘professional’ antbirds at many localities over western and southern localities; where these species are absent, the White-chinned Woodcreeper seems more numerous.

Habitat

Primarily humid forest, both terra firme and on floodplains; also forests on sandy soils in Colombia and at some sites in Brazil, and occasionally gallery, riverine or flooded forests. Prefers open understorey of interior of mature forest, less frequently subcanopy, older second growth and edges; occasionally in denser vegetation around streams, young second growth, bamboo thickets, or fringes of várzea forest. Largely restricted to forest undergrowth, using lower strata than D. fuliginosa occurring at same sites. Exclusively lowlands, generally below 300 m, occasionally to 500–600m.

Movement

Resident. Some movement within sites; even “settled” birds move over areas 2–3 km across; the sexes have overlapping territories.

Diet and Foraging

Diet consists largely of arthropods, but small vertebrates occasionally taken. Stomach contents from one site in N Bolivia mostly Hymenoptera and beetles (each comprising 33% of diet), with fewer spiders (19%) and Orthoptera (14%); other items rarely taken. Stomachs from other sites in N Bolivia and from E Peru contained primarily orthopterans, spiders and ants, with lesser numbers of beetles, cockroaches (Blattodea), bugs, vertebrates; those from Amazonian Brazil contained Hemiptera, Coleoptera, Blattaria, Isoptera, and even Odonata. Comparison of stomach contents with prey flushed by army ants revealed orthopterans are taken preferentially, with cockroaches and, especially, Hymenoptera avoided. May select prey of small to moderate size, possibly larger than taken by some other dendrocolaptids; 21% of items smaller than 7 mm, 65% were 8–16 mm, and 14% over 16 mm. Substantial overlap with other woodcreepers and several ant-following antbirds (Thamnophilidae) in both type and size of prey taken; however, this and other ant-following dendrocolaptids may take smaller items than antbirds, in relation to bill size, because they have more difficulty in removing appendages before eating prey. Prey observed taken over swarming army ants include, in decreasing order of abundance, cockroaches, spiders, ant larvae, centipedes (Chilopoda), scorpions, crickets (Gryllidae), grasshoppers (Acrididae); beetles, moths, skippers (Hesperiidae), whipscorpions (Amblypygi) and lizards all taken only on occasion. An obligate ant-follower, forages mostly over Eciton burchelli, also regularly over Labidus praedator; may visit multiple ant swarms on same day, and monitors inactive colonies; radio-tracked female with nestling routinely travelled over 300 m between ant swarms, suggesting that movements of over 500 m from nest to foraging sites perhaps not uncommon. Typically, 1–2 individuals present at swarms in Brazilian Amazon, but up to 7–8 seen at swarms in SE Peru; larger groups probably involve wandering immatures, aggregates of solitary birds, or females with young. Perches lower and often on slimmer trunks than do other woodcreepers, rarely more than 3 m above ground, often using trunks with diameter less than 15 cm. Foraging methods vary depending on presence of large antbirds such as Black-spotted Bare-eye (Phlegopsis nigromaculata). In Brazil, nearly 90% of all foraging is within 1 m of ground in absence of Phlegopsis near Manaus, where regularly remains relatively motionless on slimmer and more angled perches, but near Belém, where Phlegopsis present, only 58% of foraging below 1 m, birds move about more over ants, and they forage mostly from larger (6–15 cm diameter), near-vertical trunks. Suggested correlation between body size of these woodcreepers and presence of large antbirds not supported by small size of birds in Roraima, where large antbirds are absent. Rarely hitches far up trunks, instead flying between perches. Most prey taken by rapid sallies to ground, followed by return to perch; sallies occasionally to foliage, rarely to other substrates. Seldom picks or gleans prey from trunks or foliage. Has been observed to perform “anting”, but rarely flicks wings to flush prey. Highly aggressive towards both conspecifics and other species over ants, usually supplanting smaller species and being supplanted by larger ones; dominant over D. fuliginosa, often excluding it from foraging low over swarms, or forcing it to forage away from them. Rarely seen away from ants; at such times moves rapidly and silently through understorey, apparently in search of new swarms. Rarely follows mixed-species flocks away from ants. Radio-tracked birds observed to forage also in association with herds of peccaries (Tayassu pecari), which flush prey much as do swarming ants; one individual even seen perched atop hindquarters of a peccary.

Sounds and Vocal Behavior

Calls often heard near ant swarms, but songs poorly known; both vary geographically. Most frequent vocalization a multi-note chatter call, often given at ant swarms, usually 2–4 notes, described as “dit-it-it-it” or “tat-at-at” over most of range, but piercing “deet-eet-ee” in N Amazonia E of R Negro. Song in Manaus area (Brazil) a series of 6–9 loud, whistled notes described as “kew, kew, kew, kew, kew, kewp”, but over most of range apparently lower in frequency and described as “we, wi, di, dit”, or “wi-wid-wid-di” in SE Colombia, and in some places an ascending whistle of 2–3 notes. Other calls include sharp “spee” notes in Manaus area, growling “chauhhh”, long rattle at 4–5 notes per second (i.e. slower than D. fuliginosa), quiet “wi-i-i-i-ih” rattle, also “tsiriRIT” possibly as warning call.

Breeding

Little known. Birds in breeding condition in Feb–May in NW Brazil, E Colombia and S Venezuela, in late Jun in NE Amazonian Brazil (Amapá) and in mid-Aug in S Amazonian Brazil (Mato Grosso), and in non-breeding condition in early Oct in NE Amazonia; fledged juveniles of obidensis mid-Jul to mid-Oct, but juvenile specimens of other races mostly May–Jul; in W Amazonia, juveniles appear at ant swarms in Dec–Jan (SE Peru) and adults in moult in Oct–Apr; birds moulting in Apr in upper R Orinoco region and in worn plumage in Sept in French Guiana, suggest breeding during dry season; more work needed to confirm geographical component to variation in season. Pair-bond apparently brief; male and female associate irregularly, and for only c. 1 month, but may investigate nesting cavities together. Nest undescribed, apparently in cavity. No details on clutch size and eggs; DNA analysis revealed that female alone raises young and associates with them after fledging; male lacks brood patch, and not observed to attend young; fledglings remain with parent for 3 months (until late Jan or early Feb near Manaus), but often stay in area longer (two still present in following May); one, rarely two, dependent young encountered with single parent. Nest predation suggested as less than 80% over a breeding season of 3–6 months. Adult survival relatively high, with average annual survival 71% over 3-year period (10 of 26 birds resighted 3 years after initial capture); one bird recaptured at another site after 4 years.

Fuentes: Wikipedia/eBird/xeno-canto