Rayadito Común

Identificación

The thorn-tailed rayadito is approximately 14 centimetres (5.5 in) in length including the tail, and an average adult weighs around 11 grams (0.39 oz), with males being around 10 percent heavier than females. The most distinctive feature of a bird frequently compared to a tit is the long "thorn"-tail with twelve spiny rectrices, which gradually develops in juveniles as they mature. This thorn-tail is believed to be used, not to aid in climbing trees as in other funariids like the tit-spinetails, but to attract the opposite sex during courtship.<p>The plumage of the thorn-tailed rayadito is brown with several black lines above and generally white below in the nominate subspecies Aphrastura spinicauda spinicauda, whilst in Aphrastura spinicauda fulva of Chiloé the throat is cinnamon instead of white and in Aphrastura spinicauda bullocki of Mocha Island the dorsal side is entirely brown without black lines and the throat is white.<p>Typical voices of the thorn-tailed rayadito include:

Taxonomía

The thorn-tailed rayadito was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the wagtails in the genus Motacilla and coined the binomial name Motacilla spinicauda. Gmelin based his description on the "thorn-tailed warbler" that had been described and illustrated by the English ornithologist John Latham in his book A General Synopsis of Birds. The naturalist Joseph Banks had provided Latham with a water-colour drawing of the bird by Georg Forster who had accompanied James Cook on his second voyage to the Pacific Ocean. The picture was drawn in December 1774 at the Tierra del Fuego. This picture is held by the Natural History Museum in London. The thorn-tailed rayadito is now placed with the Masafuera rayadito in the genus Aphrastura that was introduced in 1899 by the American ornithologist Harry C. Oberholser.<p>Four subspecies are recognised:<p>The subspecies A. s. subantarctica was described in 2022 as a separate species, the Subantarctic rayadito, on the basis of genetic, morphological, and behavioral evidence.

Nombre científico

Aphrastura spinicauda

Autoridad

(Gmelin, JF, 1789)

Orden

Passeriformes

Familia

Furnariidae

Género

Aphrastura

Distribución y hábitat

It is found in noisy flocks from central Chile and adjacent Argentina, south to Tierra del Fuego.A study of the refugia used by rayaditos when the Patagonian Ice Sheet covered most of the species' existing range shows that Mocha Island was the most prominent glacial refuge and suggests the possibility that the species was present in areas to the east of the ice sheet in Argentine Patagonia, creating considerable gene flow when most of the ice sheet melted.

Migración

Especie residente

Comportamiento

Patrón migratorio: Especie residente.

Conservación

Tendencia poblacional: estable.

Tendencia poblacional

estable