What is Passerine?
{{Taxobox |name = Passerines |fossil_range = Lower [[Eocene]] to Recent |image = Passeriformes-01v01.jpg |image_width = 250px |image_caption = Clockwise from top right: [[Palestine sunbird]] (''Cinnyris osea''), [[blue jay]] (''Cyanocitta cristata''), [[house sparrow]] (''Passer domesticus''), [[great tit]] (''Parus major''), [[hooded crow]] (''Corvus cornix''), [[southern masked weaver]] (''Ploceus velatus'') |regnum = [[Animalia]] |phylum = [[Chordata]] |classis = [[Aves]] |subclassis = [[Neornithes]] |infraclassis = [[Neognathae]] |superordo = [[Neoaves]] |ordo = '''Passeriformes''' |ordo_authority = [[Linnaeus]], 1758 |diversity_link = #Taxonomic list of Passeriformes families |diversity = Roughly 140 families, around 6,500 species |subdivision_ranks = [[Suborder]]s |subdivision = *[[New Zealand wren|Acanthisitti]] *[[Tyranni]] *[[songbird|Passeri]] }} A '''passerine''' is a small or medium sized [[bird]] of the [[order (biology)|order]] '''Passeriformes''', which includes more than half of all bird species. They are [[wikt:perch|perching]] birds. Most of them are small in size, and most can sing very well. Their main [[suborder]] is the Passeri, the [[songbirds]].<ref>Sibley C.G. & Monroe B.L. Jr. 1990. ''Distribution and taxonomy of the birds of the World''. Yale Univ. Press, New Haven CT.</ref> == Adaptations == The passerines have a number of [[adaptations]] which, taken together, have made them highly successful, with many species around the world. #Perching. All passerines have four toes on each foot. Three of the toes point forwards. The other toe points backwards. This means that passerines can easily hold onto trees or rocks. Because of this, they are also known as '''perching birds'''. A [[tendon]] in the rear of the leg makes the foot curl and grip when the bird lands on a branch. This is more than just a convenience for the birds: it is a ''tendon locking mechanism'' so they can sleep without falling off.<ref>Stefoff, Rebecca (2008), ''The Bird Class'', Marshall Cavendish Benchmark</ref><ref>