Becasa Piquicorta/Short-billed Dowitcher/Limnodromus griseus

Nombre en español: Becasa Piquicorta

Nombre en inglés: Short-billed Dowitcher

Nombre científico: Limnodromus griseus

Familia: Scolopacidae

Canto: Paul Marvin

La becasina piquicorta (Limnodromus griseus) es un ave limícola playera migratoria, de la familia Scolopacidae.

Esta especie es un invernante no reproductivo en el país presente durante todo el año. Cría en Alaska e inverna desde Estados Unidos hasta Brasil. Su nombre Limnodromus significa corredor de pantanos y deriva de las raíces griegas limne = pantano y dromos = corredor. Su epíteto griseus hace referencia a su coloración, deriva del latín y significa gris.

Distribución

Migra entre Norteamérica, Centroamérica, las Antillas y Sudamérica, en hábitat muy variados, que van desde la tundra en el norte, hasta estanques y marismas en el sur, incluyendo playas arenosas, costas lodosas, manglares, lagunas y humedales de agua dulce. Abandonan completamente sus áreas de reproducción cubiertas de nieve durante el invierno del hemisferio norte y marchan al sur alcanzando desde la región del Caribe hasta Brasil.

En Colombia Se encuentra en las Costas Pacífica y Caribe.

Alimentación

Se alimenta principalmente de invertebrados, a menudo por el rápido sondeo con su pico en el barro, a la una manera máquina de coser. Consumen crustáceos, moluscos, semillas e insectos acuáticos.

Descripción

Mide en promedio 28 cm de altura. Su pico es largo y recto, con una longitud entre 6,3 y 6,8 cm. En época reproductiva el dorso presenta plumas marrón acanelado, manchado en las alas y estriado en la cabeza, parte posterior del pecho y el cuello. Tiene una banda ocular negruzca y una superciliar blanca; el vientre es rojo ladrillo con unos pocos puntos en los lados y barras en flancos.

En la época no reproductiva, el dorso es gris pardusco y el vientre blanco con algunas barras oscuras en los flancos.

La cola siempre es blanquecina con barras negruzcas. En vuelo es posible ver rabadilla blanca continuada como una cuña en la espalda; también una margen trasera blanquecina del interior del ala. Las patas son amarillas a verdosas.

Se parece bastante a la becasina piquilarga (Limnodromus scolopaceus) y las dos fueron consideradas como si fueran la misma especie, hasta 1950. No es fácil diferenciarlas en campo, pero se distinguen por sus vocalizaciones totalmente diferentes, notoriamente más suaves en las becasinas piquicortas y, porque las plumas terciarias de la piquicorta son muy manchadas mientras que en la piquilarga son de color uniforme, en tanto que el estriado de las coberteras supracaudales es más grueso en la piquicorta. La diferencia de longitud de los picos no es un criterio muy confiable de identificación, porque hay picos de diferente largo en cada especie.

Especies similares

Muy parecida a la Becasina Piquilarga (Limonodromus scolopaceus) pero esta última tiene pico más largo y barras definidas en lados y flancos, no puntos dispersos. En plumaje no reproductivo estas dos especies se distinguen únicamente por longitud del pico.

Subespecies

L. g. griseus de vientre blanco y lados rayados, anida al norte de Quebec.
L. g. hendersoni vientre rojizo y lados moteados, anida en el centro norte de Canadá.
L. g. caurinus vientre blanco, pecho muy manchado y barras gruesas a los lados, anida al sur de Alaska.
Las subespecies caurinus y griseus llegan a Colombia.

Reproducción

Anida en el suelo, generalmente cerca del agua. Sus nidos se encuentran en depresiones poco profundas, entre montones de hierba o musgo, que están alineados con finas hierbas, ramas y hojas. La hembra pone 4 y a veces 3 huevos, color oliváceo a marrón.

La incubación dura 21 días, hecha por ambos sexos. Los machos señalan el territorio realizando planeos con señales acuáticas.

Los roles de los padres no son bien conocidos, pero se ha observado que la hembra abandona el sitio reproductivo primero y deja al macho cuidando a los polluelos, que encuentran sus propios alimentos. Las aves juveniles suave abandonan el nido poco tiempo después de la eclosión.

Short-billed dowitcher

The short-billed dowitcher (Limnodromus griseus), like its congener the long-billed dowitcher, is a medium-sized, stocky, long-billed shorebird in the family Scolopacidae. The genus name Limnodromus is Ancient Greek from limne, «marsh» and dromos, «racer». The specific griseus is Medieval Latin for «grey». The English name is from Iroquois and was first recorded in 1841.

It is an inhabitant of North America, Central America, and northern South America. It is strongly migratory; it completely vacates in breeding areas during the snow-bound months. This species favors a variety of habitats including tundra in the north to ponds and mudflats in the south. It feeds on invertebrates often by rapidly probing its bill into mud in a sewing machine fashion. It and the very similar long-billed dowitcher were considered one species until 1950. Field identification of the two American Limnodromus remains difficult today. Distinguishing wintering or juvenile short-billed dowitchers from the long-billed species is very difficult and, even given examination their subtlety different body shapes, cannot always be isolated to a particular species. They differ most substantially in vocalizations. The names of American dowitchers are misleading, as there is much overlap in their bill lengths. Only a small percentage can be identified by this character alone.

Description

The body of adults is dark brown on top and reddish underneath. The tail has a black and white barred pattern. The legs are a yellowish color.

There are three subspecies with slight variations in appearance:

L. g. griseus has a white belly and barred flanks.
L. g. hendersoni has a reddish belly and spotted flanks.
L. g. caurinus has a white belly with heavily barred flanks and densely spotted breast.

None of these combines the reddish belly and barred flanks of the breeding plumage long-billed dowitcher. The winter plumage is largely grey. This bird can range from 23 to 32 cm (9.1 to 12.6 in) in length, 46 to 56 cm (18 to 22 in) in wingspan and 73–155 g (2.6–5.5 oz) in body mass.

The call of this bird is more mellow than that of the long-billed dowitcher, and is useful in identification, particularly of the difficult adult plumages.

Breeding and habitat

Their breeding habitat includes bogs, tidal marshes, mudflats or forest clearings south of the tree line in northern North America. L. g. griseus breeds in northern Quebec; L. g. hendersoni breeds in north central Canada; L. g. caurinus breeds in southern Alaska and southern Yukon.

These birds nest on the ground, usually near water. Their nests are shallow depressions in clumps of grass or moss, which are lined with fine grasses, twigs and leaves. They lay four, sometimes three, olive-buff to brown eggs. Incubation lasts for 21 days and is done by both sexes.

The downy juvenile birds leave the nest soon after hatching. Parental roles are not well known, but it is believed the female departs and leaves the male to tend the chicks, which find all their own food.

They migrate to the southern United States and as far south as Brazil. This bird is more likely to be seen near ocean coasts during migration than the long-billed dowitcher. This species occurs in western Europe only as an extremely rare vagrant.

Feeding

These birds forage by probing in shallow water or on wet mud. They mainly eat insects, mollusks, crustaceans and marine worms, but also eat some plant material.

The long-billed, medium-sized Short-billed Dowitcher is a common and conspicuous migrant along the Atlantic, Gulf, and Pacific coasts. Its breeding grounds are restricted to North America, extending nearly from coast to coast across boreal and subarctic regions of Canada and Alaska. In migration, this species prefers open coastal mud flats and saline habitats, unlike the slightly larger and more brightly colored Long-billed Dowitcher (Limnodromus scolopaceus), which tends to use freshwater pools inland.

In the late nineteenth century the Short-billed Dowitcher was so abundant as to be a prime quarry of market hunters. Nevertheless, it was¿and long remained¿one of the least understood shorebirds, largely because western populations were continually confused with the Long-billed. The situation was rectified when Frank Pitelka (1950) confirmed and extended William Rowan’s (1932) thesis that there were 2 species of New World dowitchers and that the Short-billed was polytypic. Even so, identifying dowitchers is still difficult enough that much information from areas where the 2 species occur together falls in the penumbra of «dowitcher sp.»

The Short-billed was also poorly known because its main breeding grounds are in the difficult-to-access, mosquito- and black fly¿ridden muskegs of Canada. As a result, the species’ nest and eggs avoided detection until 1906, in northern Alberta (Macoun and Macoun 1909), and that knowledge was long overlooked, because it was ascribed to Long-billed instead of the then-undescribed interior race of the Short-billed, L. griseus hendersoni (Rowan 1932).

The provenance of the dull-colored eastern dowitcher, L. g. griseus, remained enigmatic. Although deduced by elimination to lie east of Hudson Bay in the interior of Labrador (Cooke 1910; see also Forbush 1912), it was not until 1957¿1958 that R. Clement, H. Ouellet, and R. McNeil located recently fledged young in central Quebec (Todd [1963] provides a good review of this interesting chapter in North American ornithology), and the nest and eggs went undiscovered for 2 decades more (Harris 1989). Even though direct observations on nesting biology were lacking, information from migrants (Jehl 1963) showed that the females participated little, if at all, in raising the young. That finding was confirmed by studies on the breeding grounds at Churchill, Manitoba, in 1964¿1965 (Jehl unpubl.) and in Quebec in 1978¿1980 (Harris 1989). Breeding studies also showed (contra Gilliard 1958, Thompson 1964) that both sexes share incubation duties. Nevertheless, information on breeding biology was slow to accumulate because «the nests . . . must be about the hardest of all shore-birds to find» (Rowan 1927: 220).

Other dowitcher conundrums persist, including the nature of its relationships to other waders and even the origin of the name. Early American ornithologists like John James Audubon and Alexander Wilson knew it as the Red-breasted Snipe, while gunners called it Brownback. The supplanting by «dowitcher» seems to have been driven by Atlantic coast usage during the peak of the hunting era. Poynting (1895¿1896) implied that the name was common on Long Island¿a stronghold for Dutch and German immigrants. Coues (1903: 808) wrote that «dowitcher» or «dowitch» is derived from «Deutscher» or «Duitsch», which referred to the «German» or «Dutch» snipe, in distinction to «English Snipe» (= Gallinago gallinago).

Although Short-billed Dowitchers are easily observed in migration, the species has not received much study. Most of our knowledge about its migratory biology is based on studies on the Atlantic coast; west-coast birds have been largely ignored, and the scanty documentation of its breeding biology comes from only 4 areas: Alberta (e.g., Rowan 1927; Randall 1930, 1961); Churchill area of Manitoba (Taverner and Sutton 1934, Shortt and Waller 1937, Jehl and Hussell 1966a, Jehl and Smith 1970, JRJ unpubl.); southern Alaska (Hurley 1932, Shortt 1939); and Schefferville, Quebec (Todd 1963, Harris 1989).