Grass Wren

Ratona Aperdizada

Cistothorus platensis

Length: 115mm. Sexes alike. Bill brown with pearl grey mandible; iris dark brown; upper parts of head and hind neck reddish brown with fine blackish streaks; upper back pale rufous with broad and profuse black and white streaking; lower back, rump and uppertail coverts light cinnamon brown with fine black streaks. Eyebrow and throat whitish cinnamon buff; breast and belly whitish; sides of breast, flanks and undertail coverts cinnamon ochraceous; wings and tail cinnamon with profuse blackish barring.

Legs whitish pearl. Average weight: 12g. Habitat and behaviour: the Grass Wren inhabits grasslands and sedgy marshes and is found in pairs or in small loose groups. Its small size and cryptic coloration aid its rapid concealment as it moves very quickly and nimbly. Slightly crouching when scared but still curious, it climbs to the top of grasses to survey the area, swiftly disappearing upon danger. Only when forced will the Grass Wren fly, doing so at a very low altitude and for very short distances, with its tail upright. The nests are built with grass and located in tussocks, spherical in shape and lined with fibres and feathers. Clutch size: up to four white eggs. Range: widespread in Patagonia including Islas Malvinas. On the continent, the race Cistothorus platensis hornensis occurs, and at Islas Malvinas, Cistothorus platensis falklandicus.