Eurasian wren

The Eurasian wren (Troglodytes troglodytes) is a very small bird, and the only member of the wren family Troglodytidae found in Eurasia and Africa (Maghreb). In Anglophone Europe, it is commonly known simply as the wren. It was once lumped with Troglodytes hiemalis of eastern North America and Troglodytes pacificus of western North America as the winter wren. The Eurasian wren occurs in Europe, a belt of Asia from northern Iran and Afghanistan across to Japan. It is migratory in only the northern parts of its range. It is also highly polygynous, an unusual mating system for passerines. The scientific name is taken from the Greek word 'troglodytes' (from 'trogle' a hole, and 'dyein' to creep), meaning 'cave-dweller', and refers to its habit of disappearing into cavities or crevices whilst hunting arthropods or to roost. The taxonomy of the genus Troglodytes is currently unresolved, as recent molecular studies have suggested that Cistothorus spp. and Thryorchilus spp. are within the clade currently defined by Troglodytes. The Eurasian wren was described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Motacilla troglodytes. The specific epithet is from the Ancient Greek trōglodutēs 'cave-dweller'. In 1555 the German naturalist Conrad Gessner had used the Latin name Passer troglodyte for the Eurasian wren in his Historiae animalium. The species is now placed in the genus Troglodytes that was introduced by the French ornithologist Louis Pierre Vieillot in 1809. It was estimated that Troglodytes pacificus and Troglodytes troglodytes last shared a common ancestor approximately 4.3 million years ago, long before the glacial cycles of the Pleistocene, thought to have promoted speciation in many avian lineages inhabiting the boreal forest of North America.