Bienparado Grande/Great Potoo/Nyctibius grandis

Nombre en español: Bienparado Grande

Nombre en ingles: Great Potoo

Nombre científico: Nyctibius grandis

Familia: Nyctibiidae

Canto: Andrew Spencer

El nictibio grande (Nyctibius grandis), también conocido como urutaú grande, es una especie de ave caprimulgiforme perteneciente a la familia Nyctibiidae, que vive en el neotrópico.

Es el bienparado de mayor tamaño y de coloración más pálida. Llama casi exclusivamente en noches de luna. Su nombre Nyctibius significa de vida nocturna y deriva de las raíces griegas nukti = nocturno y bios = vida. Su epíteto grandis deriva del latín y significa grande.

Descripción

Mide de 45 a 55 cm y pesa de 500 a 620 g. Ambos sexos similares. Es un ave grande y robusta de cola larga y ojos oscuros. Es de color blanco grisáceo a pardusco por encima con vermiculado negruzco y ante y los hombros más oscuros. Por debajo también es blanquecino con vermiculado y barrado negruzco. Su cola es de color blanco grisáceo con 8 o 9 barras negruzcas y bordes negros bien definidos. Los jóvenes son casi completamente blancos.

Distribución y hábitat

Su área de distribución incluye México, América Central (Guatemala, Belice, El Salvador, Honduras, Nicaragua, Costa Rica) y Sudamérica (Colombia, Venezuela, Surinam, Guyana francesa, Guyana, Brasil, el noreste de Argentina, Paraguay, Ecuador, Perú y Bolivia)

Habita principalmente en el bosque húmedo tropical de tierras bajas.

En Colombia se encuentra por debajo de 400 m de altura sobre el nivel del mar al occidente de los Andes en el valle bajo del rio Atrato, en la región del rio Esmaraldas en el sur del departamento de Caldas, el Valle del rio Cesar y el valle medio del rio Magdalena. También ha sido registrada al oriente de los Andes en el departamento del Meta, Putumayo, Suroriente de Nariño y Amazonas.

Habita en bosques de tierra firme, bosques de várzea, bosques de galería en áreas de sabana, bosques secundarios y en plantaciones forestales en áreas de moderada perturbación. Con frecuencia se le encuentra a lo largo de ríos y cerca de lagos. En la noche generalmente se desplaza hacia áreas abiertas y claros cerca de bosques y durante el día descansa en el dosel de bosques perchado en árboles altos y desnudos.

Comportamiento

Es un ave solitaria y nocturna que suele posarse sobre ramas despejadas por encima del dosel, de donde se lanza para atrapar grandes insectos en el vuelo, como polillas y escarabajos, y pequeños murciélagos.

Es un ave de actividad nocturna y crepuscular que durante el día permanece posado en ramas altas y expuestas. Captura sus presas mediante vuelos desde una percha a la cual generalmente siempre retorna, generalmente en el dosel del bosque o en claros de bosque. Es un ave que llama casi exclusivamente en noches de luna.

Subespecies

Hay 2 subespecies reconocidas, incluyendo la subespecie nominal:³

Nyctibius grandis grandis (Gmelin, 1789)
Nyctibius grandis guatemalensis Land & Schultz, 1963

Solo la raza nominal se encuentra en Colombia.

Especies Similares

Individuos parduscos pueden confundirse con el Bienparado Rabilargo (Nyctibius aethereus) del cual se diferencian por el barrado y vermiculado de las partes inferiores y las bandas caudales bordeadas de negro. El Bienparado Común (Nyctibius griseus) es de menor tamaño con la cola más corta y estrechamente barrada.

Alimentación

Se alimenta principalmente de escarabajos, saltamontes y de otros insectos voladores. En ocasiones también puede capturar murciélagos pequeños.

Reproducción

Se han registrado individuos en condición reproductiva en el mes de marzo en el Golfo de Urabá e individuos anidando en el mes de abril en el departamento del Meta. Al parecer es un ave monógama. Pone un solo huevo sobre una depresión o sobre el agujero del nudo de una rama que puede ser horizontal o diagonal, generalmente en el dosel del bosque. El huevo es de color blanco con manchas de color café oscuro, gris y lila, el cual incuba el macho durante el día. La cría adquiere todo el plumaje necesario para volar cerca de 2 meses después de la eclosión.

Taxonomía

La validez de las dos subespecies reconocidas ha sido cuestionada debido a sus diferencias poco marcadas. Sin embargo, las poblaciones a ambos lados de los Andes presentan gran divergencia genética.

Great potoo

The great potoo (Nyctibius grandis) is a near passerine bird, both the largest potoo species and the largest member of the order Caprimulgiformes (nightjars and allies). They are also one of seven species in one genus, Nyctibius, located in tropical America.

Much like owls, this species is nocturnal. They prey on large insects and small vertebrates, which they capture in sallies from high perches.

Possibly its most well known characteristic is its unique moaning growl that the Great Potoo vocalizes throughout the night, creating an unsettling atmosphere in the Neotropics with its nocturnal sounds.

Description

The great potoo has a large head in relation to its body. The eyes are also very large with a brown to yellow iris and has a short but broad beak. Their wings are elliptical in shape and with an elongated tail. The feather colors vary with white, gray, black, and burgundy. The tail colors match with that of the rest of the body with the exception of white bars that can be seen going across the tail laterally. (see references below)

Range in Mass: 360g to 650g (12.69 to 22.91oz)
Range in Length: 480mm to 600mm (18.90 to 23.62 in)
Range in wingspan: 700mm to 804mm (27.56 in to 31.65 in)
Average Wingspan: 734.8mm (28.93 in)

Distribution and habitat

They range from southern Mexico through northeastern Guatemala and through most of Central America down through South America as far as Bolivia and southeastern Brazil.

In general the Great Potoo are distributed from humid to semi-humid forested habitats. While this species is widely spreadout geographically, by comparing two subspecies, there is little to no variation in their appearance such as size or plumage. The Great Potoo is found mostly in dense lowland forest, forest edges and clearings. It may also range into foothills (up to about 1,500 m elevation), second-growth, open woodlands (including plantations) and is sometimes seen around meadows, but they always require trees-etc., for their camouflaged imitative perch.

In the day they are normally found perching or nesting usually higher than 12 meters above ground level within big trees. The branches they choose to perch usually are nearly 20 to 30 centimeters in diameter. At night time, they may go to lower perches like 1.5 meters above the ground, from which they hunt.

Behavior

This nocturnal predator is usually seen perched high above the ground while foraging, sallying out when prey is spotted. After the pounce, the potoo almost always returns to its previous perch. Normally, during the day it perches upright on a tree stump, and is overlooked because it resembles part of the stump; this is a camouflage, not just by coloration, but a camouflage by the setting. The Great Potoo can be located at night by the reflection of light from its eyes as it sits vertical on a post, roost, or angled-tree trunk.

Breeding

Breeding has been recorded as typically February to August, but depending on the portion of this bird’s range breeding birds can be met with almost year-round. The nest is a slight depression on a thick tree branch, at least 10 m (33 ft) above ground, with a single white (slightly spotted) egg measuring about 5.2 x 3.8 cm (2 x 1.8 inches). Few details are known of the brooding behavior, but about a month elapses before the offspring is seen alone at the nest. A chick of a few days old weighed 220 g (7.8 oz). After about 5 weeks the nestling is a two-thirds version of the adult, but with a lighter build, paler plumage, shorter tail, and smaller bill with less rictal bristles. The fledging period must be at least 2 months. After this time span, the offspring do not return to the nest site.

Although the adult potoo likely has few natural predators, predation of eggs, nestlings and fledging is apparently not uncommon. Adults stay near the nest throughout the day and rely upon camouflage to protect their offspring. Predators of great potoo nests in Costa Rica have included monkeys such as mantled howlers, Geoffroy’s spider monkeys and white-headed capuchins as well as tayras and collared forest falcons.

Feeding

Their prey consists mostly of large flying insects, especially large beetles, katydids and Orthoptera (including crickets and grasshoppers). Bats are taken occasionally as well. The Great Potoo takes advantage of the night and its natural camouflage by sitting on an exposed perch to wait until some prey flies by, at which point it darts out towards the prey and returns to the branch with it. Very often birds of this species will use the same hunting perch nightly.

Conservation status

Due to its large range, the Great Potoo is seen as a species of least concern, according to the International Union for Conservation of Nature (IUCN). The Great Potoo is normally described as «uncommon», but occurs frequently in areas of less disturbed forests and is often found to be rare along the edges of its range. The clearing of forest is the only conservation threat known to this bird.

Effects of Humans on the Great Potoo Population

The local people in the rural area of Brazil sometimes use Potoo as a minor food source, as they do not offer much meat and are hard to locate. In these areas, their feathers are believed to have powers to provide chastity, so they are hunted down for their body parts, which are used to perform ceremonies. It is also believed that parts of their body ward off seduction.

With its characteristic drawn-out moaning growl, the vocalizations of the Great Potoo are among the most exciting and perhaps most unsettling nocturnal sounds in the Neotropics. Apart from its vocalizations, the Great Potoo is an intriguing species. Great Potoos are nocturnal and feed on large flying insects, and occasionally bats, which they capture in sallies from a high perch. During the day, they remain motionless in mimic of broken tree branches. The Great Potoo is distributed throughout humid and semihumid forested habitats in Central and South America. Across this vast region, there is little geographic variation in size or in plumage; two subspecies sometimes are recognized, but these do not differ greatly from each other. Despite the lack of conspicuous geographic variation, populations on either side of the Andes have been found to be very distinct genetically. This level of divergence is similar to the genetic divergence found between other species of potoo, pointing the possibility for ‘cryptic’ species within the Great Potoo lineage.