Wrens are a family of brown passerine birds in the predominantly New World family Troglodytidae. The family includes 88 species divided into 19 genera. Only the Eurasian wren occurs in the Old World, where, in Anglophone regions, it is commonly known simply as the "wren", as it is the originator of the name. The name wren has been applied to other, unrelated birds, particularly the New Zealand wrens (Acanthisittidae) and the Australian wrens (Maluridae).
Most wrens are visually inconspicuous though they have loud and often complex songs. Exceptions include the relatively large members of the genus Campylorhynchus, which can be quite bold in their behaviour. Wrens have short wings that are barred in most species, and they often hold their tails upright. Wrens are primarily insectivorous, eating insects, spiders and other small invertebrates, but many species also eat vegetable matter and some eat small frogs and lizards.
Etymology and usage
The English name "wren" derives from and , attested (as ) very early, in an eighth-century gloss. It is cognate to , , and (the latter two including an additional diminutive -ilan suffix). The Icelandic name is attested in Old Icelandic (Eddaic) as . This points to a Common Germanic name , but the further etymology of the name is unknown.
The wren was also known as the ('kinglet') in Old High German, a name associated with the fable of the election of the "king of birds". The bird that could fly to the highest altitude would be made king. The eagle outflew all other birds, but he was beaten by a small bird that had hidden in his plumage. This fable was already known to Aristotle (Historia Animalium 9.11) and Pliny (Natural History 10.95), and was taken up by medieval authors such as Johann Geiler von Kaisersberg, but it most likely originally concerned kinglets (, such as the goldcrest) and was apparently motivated by the yellow "crown" sported by these birds (a point noted already by Ludwig Uhland). The confusion stemmed in part from the similarity and consequent interchangeability of the Ancient Greek words for the wren ( , 'king') and the crest ( , 'kinglet'), and the legend's reference to the "smallest of birds" becoming king likely led the title to be transferred to the equally tiny wren. In modern German, the name of the bird is ('king of the fence (or hedge)') and in Dutch, the name is ('king of winter').
The family name Troglodytidae is derived from troglodyte, which means 'cave-dweller'. Wrens get their scientific name from the tendency of some species to forage in dark crevices.
The name "wren" is also ascribed to other families of passerine birds throughout the world. In Europe, kinglets are commonly known as "wrens", with the common firecrest and goldcrest known as the "fire-crested wren" and "golden-crested wren", respectively.
The 27 Australasian "wren" species in the family Maluridae are unrelated, as are the New Zealand wrens in the family Acanthisittidae, the antbirds in the family Thamnophilidae, and the Old World babblers of the family Timaliidae.
Description
Wrens are medium-small to very small birds. The Eurasian wren is among the smallest birds in its range, while the smaller species from the Americas are among the smallest passerines in that part of the world. They range in size from the white-bellied wren, which averages under and , to the giant wren, which averages about and weighs almost . The dominating colors of their plumage are generally drab, composed of gray, brown, black, and white, and most species show some barring, especially on the tail or wings. No sexual dimorphism is seen in the plumage of wrens, and little difference exists between young birds and adults. All have fairly long, straight to marginally decurved (downward-curving) bills.
Wrens have loud and often complex songs, sometimes given in duet by a pair. The songs of members of the genera Cyphorhinus and Microcerculus have been considered especially pleasant to the human ear, leading to common names such as song wren, musician wren, flutist wren, and southern nightingale-wren.