Des Murs´s Wiretail

Belongs to an extraordinary and highly specialized lineage of Neotropical ovenbirds, characterized by a strikingly elongated, wire-like tail that significantly exceeds its body size. This tiny passerine reaches a total length of approximately 24 centimeters, yet the actual body spans a mere 7 to 8 centimeters, weighing between 7 and 9 grams. Its tail is composed of only six rectrices—reduced from the typical twelve found in most passerines—with the central pair being exceptionally long, thin, and filament-like. The plumage is mostly warm brown or rufous on the upperparts, transitioning to a pale buffish-white on the throat and underparts. It features a distinctive, pale whitish supercilium above its dark eyes, and a slender, slightly decurved bill adapted for probing tight crevices in search of prey.

Geographical distribution: Is endemic to the temperate and sub-Antarctic regions of southwestern South America. Its range is primarily restricted to Chile, extending from the Coquimbo and Valparaíso regions southwards to the northern parts of the Magallanes region. It is also found in the adjacent border regions of southwestern Argentina, spanning from the province of Neuquén down to northwestern Santa Cruz, closely associated with the humid eastern slopes of the southern Andes.

Habitat: Is strictly associated with the dense understory of the Valdivian temperate rainforests. It shows a specialized preference for microhabitats dominated by dense bamboo thickets of the genus Chusquea, locally known as colihue, as well as shaded areas rich in giant ferns, mossy trunks, and damp shrubbery near forest edges or streams. It rarely ventures into the open, preferring the dark, highly humid, and structurally complex lower strata of primary and mature secondary forests.

Feeding: Is predominantly insectivorous, foraging meticulously for small invertebrates within the dense foliage. Its diet consists of spiders, beetles, aphids, larvae, and small flies. To capture its prey, this species exhibits highly active and agile behaviors, creeping and hopping acrobatically among vertical bamboo stems and tangled branches close to the forest floor. It inspects moss clumps, leaf litter, and the undersides of leaves, using its sharp bill to pluck hidden insects with great precision.

Behavior: Is a remarkably secretive and elusive bird, making it far more frequently heard than seen. Due to the heavy aerodynamic drag of its extremely long tail, its flight is weak, undulating, and limited to short, fluttering hops between dense vegetation. It is usually found singly or in territorial pairs. It maintains contact within the thick undergrowth through a distinctive, high-pitched, insect-like trill that starts slowly and accelerates rapidly, serving as an essential acoustic signal in its low-visibility habitat.

Nesting: Occurs during the southern hemisphere spring and summer, typically between October and January. The breeding pairs build a large, dome-shaped, globular nest featuring a small lateral entrance hole. The nest is constructed of fresh moss, dry grasses, lichens, and fine rootlets, and is securely hidden low to the ground inside dense clumps of Chusquea bamboo or ferns. The female typically lays a clutch of 2 to 4 pure white eggs, which are incubated by both parents. Both adults actively participate in brooding and feeding the altricial nestlings until they fledge.

Conservation status: Is currently evaluated as Least Concern (LC) on the IUCN Red List. Although the species is not globally threatened, its specialized habitat requirements make it highly vulnerable to habitat fragmentation, commercial logging, and the clearing of native understory vegetation. Forest fires and the grazing of domestic livestock in forested areas pose significant threats by destroying the crucial bamboo understory upon which this unique bird relies.