From New World Encyclopedia

Fringilla coelebs (chaffinch), male
Fringilla coelebs (chaffinch), male
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Linnaeus, 1758
  • Acanthisitti
  • Tyranni
  • Passeri

A passerine or passeriform is a member of the order Passeriformes, the largest order of birds, containing more than half of all species. They are also known as perching birds or, less accurately, as songbirds (which actually compose a suborder of Passeriformes). The passerines form one of the most spectacularly diverse terrestrial vertebrate orders; with around 5,400 known species, it is roughly twice as diverse as the largest of the mammal orders, Rodentia.

The passerines, with their diverse forms, colors, and behaviors, and with many adding song to the sounds around us, add an important component to the joy that humans feel in experiencing nature.

The passerines are true perching birds, having four toes, with three directed forward and one backward. The order includes such birds as finches, warblers, and jays. The group gets its name from the Latin name for the house sparrow, Passer domesticus.


The foot of a passerine is specialized for holding onto a branch, with three toes directed forward without any webbing or joining, and one toe directed backward. The hind toe joins the leg at the same level as the front toes. In other orders of birds, the toe arrangement is different. Passerines generally have sharp, curved claws.

Passerines are all terrestrial, found on all continents except Antarctica.

Most passerines are smaller than typical members of other avian orders. The heaviest passerines are the thick-billed raven and the common raven (1.5 to 3.6 pounds). Two species of lyrebird are longer overall. The superb lyrebird or Weringerong, (Menura novaehollandiae), reaches 31-39 inches long in males and 29-33 inches long in females, and the Albert's lyrebird (Menura alberti) reaches a maximum of about 35 inches in males and 33 inches in females.

Most passerines lay colored eggs, in contrast to non-passerines, who lay mostly white eggs, except in some ground nesting groups such as Charadriiformes and nightjars, where camouflage is necessary, and some parasitic cuckoos, who have to match the passerine host's egg. The pigments biliverdin and its zinc chelate provide a green or blue ground color for passerine eggs, while protoporphyrin produces reds and browns used as a base color or as spotting.


The order typically is divided into two suborders, Tyranni (suboscines), and Passeri (oscines).

  • Passeri: A songbird or oscine is a bird belonging to the suborder Passeri. These include about four thousand species. In the oscines, the vocal organ is developed in such a way as to produce various sound notes, commonly known as a bird song. Oscines have the most control of their syrinx muscles among birds, producing a wide range of songs and other vocalizations. Song birds include lyrebirds, blackbirds, jays, larks, sparrows, warblers, finches, wrens, starlings, and cowbirds.
  • Tyranni: The suboscines include about one thousand species, the large majority of which are South American. These have a different anatomy of the syrinx musculature than the songbirds. The suboscines include antbirds, flycatchers, and woodcreepers.
  • Acanthisitti: The New Zealand wrens, Acanthisittidae, are a family of tiny passerines endemic to New Zealand. They are represented by six or seven known species in four or five genera, although only two species survive today. They are understood to form a distinct lineage within the passerines, but authorities differ on their assignment to the oscines or suboscines. More recent studies suggest that they form a third, most ancient, suborder, Acanthisitti, and have no living close relatives at all. They are called "wrens" due to their similar appearance and behavior, but are not related to true wrens (Troglodytidae) of the northern hemisphere.

Some other classifications may list the broadbills as their own suborder, Eurylaimi, and the lyrebirds as their own suborder Menurae, both being listed with Tyranni as suboscines.

Origin and Evolution

The evolutionary history of and relationships among the passerine families remained rather mysterious until around the end of the twentieth century. Many passerine families were grouped together on the basis of morphological similarities that, it is now believed, are the result of convergent evolution, rather than a close genetic relationship. For example, the "wrens" of the northern hemisphere, Australia, and New Zealand, all look very similar and behave in similar ways, but belong to three far-flung branches of the passerine family tree; they are as unrelated as it is possible to be while yet remaining Passeriformes.

Much research remains to be done, but advances in molecular biology and improved paleobiogeographical data are gradually revealing a clearer picture of passerine origins and evolution. It is now thought that the early passerines evolved in Gondwana at some time in the Paleogene, maybe around the Late Paleocene (about 60-55 million years ago). The initial split was between the Tyranni (the ancestors of the songbirds), the Eurylaimides, and the New Zealand "wrens", which must have diverged during a short period of time (some million years at best). The Passeriformes apparently evolved out of a fairly close-knit clade of "near passerines" which contains such birds as the Piciformes, Coraciiformes, and Cuculiformes (Johnasson and Ericson, 2003).

A little later, a great radiation of forms took place out of Australia-New Guinea: the Passeri or songbirds. A major branch of the passerine tree, the Passerida, emerged either as the sister group to the basal lineages and corvoids (Parvorder Corvida), or more likely as a subgroup of it, and expanded deep into Eurasia and Africa, where there was a further explosive radiation of new lineages. This eventually led to the corvoidan clade, three major passeridan lineages, and numerous minor lineages making up songbird diversity today. There has been extensive biogeographical mixing, with northern forms returning to the south, southern forms moving north, and so on.

Fossil Record

Perching bird osteology, especially of the leg bones, is rather diagnostic. Still, the first Passeriformes were apparently forms on the small side of the present size range, and their delicate bones did not preserve well. QM specimens F20688 (carpometacarpus) and F24685 (tibiotarsus) from Murgon, Queensland are fossil bone fragments clearly recognizable as passeriform; they support the view that some 55 million years ago, early perching birds were recognizably distinct. The Murgon fossils represent two species of approximately ten to 20 centimeters overall length. A quite similar group, the Zygodactylidae (named for their zygodactylous approach to perching) independently arose at much the same time—and possibly from closely-related ancestors—in the landmasses bordering the North Atlantic, which at that time was only some two-thirds of its present width.

Until the discovery of the Australian fossils, it was believed for some time that Palaeospiza bella from the Priabonian Florissant Fossil Beds (Late Eocene, around 35 million years ago) was the oldest known passeriform. However, it is now considered a non-passeriform near passerine.

In Europe, perching birds are not too uncommon in the fossil record from the Oligocene onward, but most are too fragmentary for a more definite placement:

  • Wieslochia (Early Oligocene of Frauenweiler, Germany)
  • Passeriformes gen. et sp. indet. SMF Av 504 (Late Oligocene of Luberon, France) - suboscine
  • Passeriformes gen. et sp. indet. (Late Oligocene of France)
  • Passeriformes gen. et sp. indet. SMN Av 487-496 (Middle Miocene of Petersbuch, Germany)
  • Passeriformes gen. et sp. indet. (Sajóvölgyi Middle Miocene of Mátraszõlõs, Hungary) - 3 spp.: Passeroidea, Muscicapoidea, Paridae?
  • Passeriformes gen. et sp. indet. SMNS 86822,86825-86826

A set of Early/Middle Miocene (approx. 15 million years ago) fossils from Sansan, France (MNHN SA 1259-1263) is doubtfully passeriform. The fact that the Passeri expanded much beyond their region of origin is proven by an undetermined broadbill (Eurylaimidae) from the Early Miocene (roughly 20 million years ago) of Wintershof, Germany, and the indeterminate Late Oligocene suboscine from France listed above. Wieslochia was apparently not a member of any extant suborder either. Extant Passeri superfamilies were well distinct by about 13-12 million years ago and modern genera were present in the corvoidean and basal songbirds. The modern diversity of Passerida genera evolved mostly from the Late Miocene onward and into the Pliocene (about 10-2 million years ago). Pleistocene lagerstätten (<1.8 million years ago) yield numerous to near-exclusively extant species, or their chronospecies and paleosubspecies.

In the Americas, the fossil record is more scant. Apart from the indeterminable MACN-SC-1411 (Pinturas Early/Middle Miocene of Santa Cruz Province, Argentina), an entirely extinct lineage of perching birds has been described from the United States:

  • Palaeoscinidae
    • Paleoscinis (Late Miocene of California)

Taxonomic List of Passeriformes Families

This list is one proposed taxonomic order. It places related species/groups next to each other. The subdivisions follow Lovette and Bermingham's 2000 study of the c-mos proto-oncogene nDNA sequence.

Initially the Corvida and Passerida were classified as "parvorders" in the suborder Passeri; in accord with the usual taxonomic practice, they would probably be ranked as infraorders. As originally envisioned they contained the superfamilies Corvoidea and minor lineages, and the superfamilies Sylvioidea, Muscicapoidea, and Passeroidea, respectively.

Several taxa turned out to be isolated species-poor lineages and consequently new families had to be established; it seems likely that in the Passeri alone, a number of minor lineages will eventually be recognized as distinct superfamilies. For example, the kinglets constitute a single genus with less than ten species, but seem to have been among the first perching bird lineages to diverge as the group spread across Eurasia. No particularly close relatives of them have been found among comprehensive studies of the living Passeri. Likewise, major "wastebin" families such as the Old World warblers and Old World babblers have turned out to be paraphyletic.

This process is still continuing. Therefore, the arrangement as presented here is not definite and may be subject to change.

Regarding arrangement of families: The families are sorted into a somewhat unusual sequence. This is because so many reallocations have taken place since about 2005 that a definite arrangement has not been established yet. It was attempted to preserve as much of the former arrangement, while giving priority to adequately address the relationships between the families.

Suborder Acanthisitti

  • Acanthisittidae: New Zealand "wrens"

Suborder Tyranni


  • Infraorder Eurylaimides - Old World suboscines (or Broad-billed suboscines; probably a separate suborder)
    • Superfamily Eurylaimoidea - broadbills and allies
      • Eurylaimidae: broadbills
      • Philepittidae: asities
      • Sapayoidae: Broad-billed Sapayoa
    • Superfamily Pittoidea
      • Pittidae: pittas
  • Infraorder Tyrannides - New World suboscines
    • Superfamily N.N. - "bronchophones"
      • Tyrannidae: tyrant flycatchers
      • Cotingidae: cotingas
      • Pipridae: manakins
    • Superfamily Furnarioidea - tracheophones
      • Furnariidae: ovenbirds and woodcreepers
      • Thamnophilidae: antbirds
      • Formicariidae: antpittas, antthrushes, and typical tapaculos (possibly polyphyletic)
      • Conopophagidae: gnateaters and gnatpittas
      • N.N.: atypical "tapaculos" (crescent-chests and allies)

Suborder Passeri

Songbirds or oscines

  • "Parvorder" Corvida (paraphyletic)
    • Menuridae: lyrebirds
    • Atrichornithidae: scrub birds
    • Climacteridae: Australian treecreepers
    • Maluridae: fairy-wrens, emu-wrens, and grasswrens
    • Meliphagidae: honeyeaters and chats
    • Promeropidae: sugarbirds
    • Pardalotidae: pardalotes, scrubwrens, thornbills, and gerygones
    • Petroicidae: Australian robins
    • Orthonychidae: logrunners
    • Pomatostomidae: Australasian babblers
    • Cinclosomatidae: whipbirds and allies
    • Neosittidae: sittellas
    • Pachycephalidae: whistlers, shrike-thrushes, pitohuis, and allies
    • Dicruridae: monarch flycatchers and allies
    • Campephagidae: cuckoo shrikes and trillers
    • Oriolidae: orioles and Figbird
    • Paramythiidae: tit berrypecker and crested berrypecker - formerly in Passerida
    • Melanocharitidae: berrypeckers and longbills - formerly in Passerida
    • Artamidae: wood swallows, butcherbirds, currawongs, and Australian Magpie
    • Paradisaeidae: birds of paradise
    • Corvidae: crows, ravens, and jays
    • Corcoracidae: White-winged Chough and Apostlebird
    • Irenidae: fairy-bluebirds
    • Chloropseidae: leafbirds - tentatively placed here
    • Laniidae: shrikes
    • Prionopidae: helmetshrikes
    • Malaconotidae: puffback shrikes, bush shrikes, tchagras, and boubous
    • Pityriaseidae: Bornean Bristlehead
    • Platysteiridae: wattle-eyes or puffback flycatchers - formerly in Passerida
    • Aegithinidae: ioras - tentatively placed here
    • Vireonidae: vireos
    • Vangidae: vangas
    • Ptilonorhynchidae: bowerbirds
    • Turnagridae: Piopio
    • Callaeidae: New Zealand wattlebirds
    • Family N.N.: Stitchbird
    • Picathartidae: rockfowl - Tentatively placed here.
    • Chaetopidae: rock-jumpers. Recently split from Turdidae. Tentatively placed here.
  • Infraorder Passerida
    • Superfamily Sylvioidea - mostly insectivores, distribution centered on the Indo-Pacific region. Few occur in the Americas.
      • Alaudidae: larks
      • Hirundinidae: swallows and martins
      • Phylloscopidae: leaf-warblers and allies. Recently split from Sylviidae.
      • Aegithalidae: long-tailed tits
      • Cettiidae: ground-warblers and allies. Recently split from Sylviidae.
      • Megaluridae: grass-warblers and allies. Recently split from Sylviidae.
      • "Bernieridae": Malagasy warblers. A newly assembled family.
      • Acrocephalidae: marsh- and tree-warblers. Recently split from Sylviidae.
      • Pycnonotidae: bulbuls
      • Cisticolidae: cisticolas and allies
      • Sylviidae: "true/sylviid warblers" and parrotbills. Might be merged into Timaliidae. Monophyly needs confirmation.
      • Zosteropidae: white-eyes. Probably belongs into Timaliidae.
      • Timaliidae: babblers. Monophyly needs confirmation.
      • Sylvioidea incertae sedis
        • "African warblers": A proposed clade, but monophyly needs confirmation. Formerly in Sylviidae.
        • Donacobius: Black-capped Donacobius. Monotypic family? Tentatively placed here; possibly closest to Megaluridae. Formerly in Troglodytidae.
        • Nicator: Relationships unresolved, monotypic family? Tentatively placed here; formerly in Pycnonotidae.
        • Panurus: Bearded Reedling (Bearded "Tit"). Relationships enigmatic, monotypic family Panuridae? Tentatively placed here; formerly in "Paradoxornithidae."
    • Superfamily Muscicapoidea - mostly insectivores, near-global distribution centered on Old World tropics. One family endemic to Americas.
      • Cinclidae: dippers
      • Muscicapidae: Old World flycatchers and chats. Monophyly needs confirmation.
      • Turdidae: thrushes and allies. Monophyly needs confirmation.
      • Buphagidae: oxpeckers. Formerly usually included in Sturnidae.
      • Sturnidae: starlings and possibly Philippine creepers. Placement of latter in Muscicapoidea seems good, but inclusion in Sturnidae requires confirmation; possibly distinct family Rhabdornithidae.
      • Mimidae: mockingbirds and thrashers
    • Superfamily Passeroidea - mostly herbivores, near-global distribution centered on Palearctic and Americas. Includes the Nine-primaried oscines (probably a subclade).
      • Passeridae: true sparrows
      • Prunellidae: accentors
      • Motacillidae: wagtails and pipits
      • Urocynchramidae: Przewalski's Finch. Recently split from Fringillidae; tentatively placed here.
      • Peucedramidae: Olive Warbler
      • Estrildidae: estrildid finches (waxbills, munias, etc)
      • Ploceidae: weavers
      • Viduidae: indigobirds and whydahs
      • Fringillidae: true finches. Possibly polyphyletic.
      • Drepanididae: Hawaiian honeycreepers. Might be merged into Fringillidae.
      • Icteridae: grackles, New World blackbirds, and New World orioles
      • Parulidae: New World warblers
      • Thraupidae: tanagers and allies
      • Cardinalidae: cardinals
      • Emberizidae: buntings and American sparrows
      • Passeroidea incertae sedis
        • Coerebidae: Bananaquit. Family invalid or not monotypic; reallocation pending.
    • Passerida incertae sedis - Rather basal Passerida, most of which seem to constitute several small but distinct superfamilies. Most occur in Asia, Africa and North America
      • Possible superfamily "Dicaeoidea" - sunbirds and flowerpeckers
        • Nectariniidae: sunbirds
        • Dicaeidae: flowerpeckers
      • Possible superfamily Bombycilloidea - waxwings and allies
        • Bombycillidae: waxwings
        • Dulidae: Palmchat. Tentatively placed here.
        • Ptilogonatidae: silky flycatchers. Tentatively placed here.
        • Hypocoliidae: Hypocolius. Tentatively placed here.
      • Possible superfamily Paroidea - titmice and allies
        • Paridae: tits, chickadees, and titmice
        • Remizidae: penduline tits. Sometimes included in Paridae.
        • Stenostiridae: stenostirids ("flycatcher-tits"). A newly assembled family; sometimes included in Paridae.
      • Possible superfamily Sittoidea or Certhioidea - wrens and allies.
        • Sittidae: nuthatches
        • Tichodromadidae: Wallcreeper. Tentatively placed here.
        • Certhiidae: treecreepers
        • Salpornithidae: Spotted Creeper. Tentatively placed here; might belong into Certhidae.
        • Troglodytidae: wrens
        • Polioptilidae: gnatcatchers
      • Possible monotypic superfamily N.N.
        • Promeropidae: sugarbirds
      • Possible monotypic superfamily N.N.
        • Family N.N.: Hyliotas. Recently split from Sylviidae.
      • Possible superfamily Reguloidea - kinglets. Tentatively placed here.
        • Regulidae: kinglets

See also

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