Editing Passerine (section)

==Anatomy==
The foot of a passerine has three toes directed forward and one toe directed backward, called [[anisodactyl]] arrangement. The hind toe ([[hallux]]) is long and joins the leg at approximately the same level as the front toes. This arrangement enables passerine birds to easily perch upright on branches. The toes have no webbing or joining, but in some [[cotinga]]s, the second and third toes are united at their basal third.

The leg of passerine birds contains an additional special adaptation for perching. A tendon in the rear of the leg running from the underside of the toes to the muscle behind the [[tibiotarsus]] will automatically be pulled and tighten when the leg bends, causing the foot to curl and become stiff when the bird lands on a branch. This enables passerines to sleep while perching without falling off.<ref>{{cite book|last =Stefoff|first = Rebecca |date =2008|isbn = 9780761426936|title = The Bird Class |publisher =  Marshall Cavendish Benchmark}}</ref><ref>Brooke, Michael and Birkhead, Tim (1991) ''The Cambridge Encyclopedia of Ornithology'', Cambridge University Press {{ISBN|0521362059}}.</ref>

Most passerine birds have 12 tail feathers but the [[superb lyrebird]] has 16,<ref>Jones, D. (2008) "Flight of fancy". ''Australian Geographic'', (89), 18–19.</ref> and several spinetails in the family [[Furnariidae]] have 10, 8, or even 6, as is the case of [[Des Murs's wiretail]]. Species adapted to tree trunk climbing such as [[treecreepers]] and [[woodcreeper]] have stiff tail feathers that are used as props during climbing.<ref>{{Cite journal |last1=Claramunt |first1=Santiago |last2=Derryberry |first2=Elizabeth P. |last3=Brumfield |first3=Robb T. |last4=Remsen |first4=J. V. |date=May 2012 |title=Ecological Opportunity and Diversification in a Continental Radiation of Birds: Climbing Adaptations and Cladogenesis in the Furnariidae |url=https://www.journals.uchicago.edu/doi/10.1086/664998 |journal=The American Naturalist |language=en |volume=179 |issue=5 |pages=649–666 |doi=10.1086/664998 |pmid=22504546 |bibcode=2012ANat..179..649C |s2cid=205998536 |issn=0003-0147}}</ref> Extremely long tails used as sexual ornaments are shown by species in different families. A well-known example is the [[long-tailed widowbird]].