Chiloe Wigeon

Pato Overo

Anas sibilatrix

Length: 500mm. Sexes slightly unlike. Male: bill light bluish grey with black nail; iris dark brown; forehead, lores and malar region white; auriculars white with blackish mottling; remainder of head black except in the posterior part of the sides of head and neck, which is black with striking blue and green metallic sheen; rest of neck blackish brown; anterior part of breast with alternating whitish and blackish bars; rest of breast and abdomen white; flanks rusty chestnut; under tail coverts white with rusty chestnut spotting. Upper back blackish with white-edged feathers; scapulars and tertiaries, likewise; lower back blackish brown; rump and uppertail coverts white; tail blackish. Lesser and median inner wing coverts blackish; outer median wing coverts and greater coverts white; secondaries velvet black, speculum likewise; primaries blackish brown with paler inner vexillum. Legs dark grey. Female: bill and iris as male; posterior part of sides of head and neck blackish with a faint bluish sheen; rest of body plumage as in male but duller; lesser and inner median wing coverts greyish brown; secondaries likewise.

Legs similar to male but smaller in size. Young plumage resembles adults but paler and browner overall. Habitat and behaviour: very common and easily identified, found in pairs or groups that number up to 30 or more individuals; quite boisterous, in feeding or roosting grounds the whistling of males and nasal vocalisations of females can be heard, creating a cheerful and festive environment. In order to fly, it springs up; its flight is quick with vigorous wing beats, and while airborne, it emits its characteristic calls and whistling. It generally inhabits ponds, rivers, streams and lakes; also found in shallow pools, grassy marshes and sea shores. It feeds on vegetation; walks long distances from water to feed on grass.

The Chiloe Wigeon nests on the ground, hidden in vegetation, close or a long way from water; nests are built in a hollow on the ground, lined with grass and covered with abundant down; clutch size: 6-10 cream white eggs. Range: from Río Negro and Neuquén to Tierra del Fuego and Islas Malvinas. Also found in Entre Ríos, Santa Fe, Buenos Aires, Córdoba; La Pampa and Mendoza; in winter part of the population migrates to southern Brazil, Paraguay and Uruguay. In Chile it is found from Atacama to the Chilean Tierra del Fuego.