Pato Collarejo/Ring-necked Duck/Aythya collaris

Nombre en español: Pato Collarejo

Nombre en inglés: Ring-necked Duck

Nombre científico: Aythya collaris

Categorías: Errática / Migratoria / Boreal

Canto: Andrew Spencer

El porrón acollarado (Aythya collaris) es un pequeño pato buceador de Norteamérica.

El macho adulto es similar en el patrón de color a su pariente el porrón moñudo de la región de Eurasia. Tiene el pico gris con una banda blanca, la cabeza es de color púrpura brillante, el pecho blanco, los ojos amarillos y plumas gris oscuras en la espalda. La hembra adulta tiene la cabeza marrón pálida y el cuerpo y la espalda de color marrón oscuro, el pico es oscuro con una banda más clara que el del macho, y sus ojos son de color marrón. El anillo del cuello canela suele ser difícil de observar, a diferencia del anillo blanco en su pico, por lo que a veces se refiere a esta ave como “pato anillo de pico” (en inglés: «ringbill»).

Su hábitat son los lagos o estanques de los bosques en el norte de Estados Unidos y Canadá. Pasan el invierno en el sur de América del Norte, generalmente en lagos, estanques, ríos o bahías. Unos pocos especímenes de esta especie migratoria, viajan regularmente al oeste de Europa. Inclusive cada año, varios patos migran hasta América Central, tan al sur como Costa Rica, entre octubre – noviembre y mayo – junio.

Estas aves se alimentan principalmente por medio del buceo. Comen plantas acuáticas, así como algunos moluscos, insectos acuáticos y pequeños peces.

El nido tiene forma de cuenco, construido con vegetación acuática, en un lugar seco, cerca de agua. La hembra pone de 8 a 10 huevos, y permanecen junto a sus crías hasta que estas son capaces de volar.

Ring-necked duck

The ring-necked duck (Aythya collaris) is a diving duck from North America commonly found in freshwater ponds and lakes. The scientific name is derived from Greek aithuia, an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin collaris, «of the neck» from collum, «neck».

Description

Ring-necked duck male, showing the cinnamon neck-ring

Ring-necked ducks are small to medium-sized diving ducks with the following length, weight, and wingspan measurements:

Length: 15.3-18.1 in (39-46 cm)
Weight: 17.3-32.1 oz (490-910 g)
Wingspan: 24.4-24.8 in (62-63 cm)

The adult male is similar in color pattern to the Eurasian tufted duck, its relative. Males are a little bit bigger than the female. It has two white rings surrounding its gray bill, a shiny black angular head, black back, white line on the wings, a white breast and yellow eyes. The adult female has a grayish brown angular head and body with a dark brown back, a dark bill with a more subtle light band than the male, grayish-blue feet and brown eyes with white rings surrounding them. Females also make a noise like trrr. The cinnamon neck ring is usually difficult to observe, which is why the bird is sometimes referred to as a «ringbill».

Breeding and migration

Their breeding habitat is wooded lakes or ponds in the northern United States and Canada. The main breeding area is Northwest boreal forest territories. Their breeding habits also take place in the eastern boreal region of Canada but no where near the same amount in the northwestern region. In the winter months they are usually found in southern North America in lakes, ponds, rivers or bays. Ring-necked duck pairs start during spring migration. Unpaired ducks showing up on breeding grounds will most likely end up being non-breeders. The pairs stay together only for reproduction, after that, they separate. The nest is bowl-shaped, built on water in dense emergent vegetation with sedges and woody plants. The female lays one egg per day until 8 to 10 eggs are laid. They are incubated 25–29 days and the female may remain with the young until they are able to fly.

Diet

These birds are omnivores and feed mainly by diving or dabbling at the surface. Ducklings are dependent on animal matter such as insects, earthworms, leeches, midges and snails. As they mature they tend change their diet to submerged plants such as pondweed and coontail, and emergents such as annual wild rice and snails.

Vagrancy

This strong migrant is a rare but regular vagrant to western Europe. In Britain, occasional small flocks occur, including five at Loch Leven, Scotland in September 2003 and four at Standlake in Oxfordshire in April 2015. In Ireland one or two individuals can be seen at any time of year. Vagrant individuals also occur each year in Central America as far south as Costa Rica between October/November and May/June. They have also been reported in small numbers in Suriname and French Guiana, in northern South America.