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. The English name "wren" derives from wrenne and wrænna, attested (as wernnaa) very early, in an eighth-century gloss. It is cognate to wrendo, wrendilo, and rindill (the latter two including an additional diminutive -ilan suffix). The Icelandic name is attested in Old Icelandic (Eddaic) as rindilþvari. This points to a Common Germanic name wrandjan-, but the further etymology of the name is unknown. The wren was also known as the kuningilin ('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 (Regulus, such as the goldcrest) and was apparently motivated by the yellow "crown" sported by these birds (a point noted already by Ludwig Uhland).