Passerine

The order is divided into three suborders, Tyranni (suboscines), Passeri (oscines or songbirds), and the basal Acanthisitti.[6] Oscines have the best control of their syrinx muscles among birds, producing a wide range of songs and other vocalizations, though some of them, such as the crows, do not sound musical to human beings. Some, such as the lyrebird, are accomplished mimics.[7] The New Zealand wrens are tiny birds restricted to New Zealand, at least in modern times; they were long placed in Passeri.

Pterylosis or the feather tracts in a typical passerine

Most passerines are smaller than typical members of other avian orders. The heaviest and altogether largest passerines are the thick-billed raven[8] and the larger races of common raven, each exceeding 1.5 kg (3.3 lb) and 70 cm (28 in). The superb lyrebird and some birds-of-paradise, due to very long tails or tail coverts, are longer overall. The smallest passerine is the short-tailed pygmy tyrant, at 6.5 cm (2.6 in) and 4.2 g (0.15 oz).[9]

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 cotingas, 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.[10][11]

Most passerine birds have 12 tail feathers but the superb lyrebird has 16,[12] 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.[13] Extremely long tails used as sexual ornaments are shown by species in different families. A well-known example is the long-tailed widowbird.

The chicks of passerines are altricial: blind, featherless, and helpless when hatched from their eggs. Hence, the chicks require extensive parental care. Most passerines lay colored eggs, in contrast with nonpasserines, most of whose eggs are white except in some ground-nesting groups such as Charadriiformes and nightjars, where camouflage is necessary, and in some parasitic cuckoos, which match the passerine host's egg. The vinous-throated parrotbill has two egg colors, white and blue, to deter the brood parasitic common cuckoo.

Clutches vary considerably in size: some larger passerines of Australia such as lyrebirds and scrub-robins lay only a single egg, most smaller passerines in warmer climates lay between two and five, while in the higher latitudes of the Northern Hemisphere, hole-nesting species like tits can lay up to a dozen and other species around five or six. The family Viduidae do not build their own nests, instead, they lay eggs in other birds' nests.

The evolutionary history of the passerine families and the relationships among them remained rather mysterious until the late 20th century. In many cases, passerine families were grouped together on the basis of morphological similarities that, it is now believed, are the result of convergent evolution, not a close genetic relationship. For example, the wrens of the Americas and Eurasia, those of Australia, and those of New Zealand look superficially similar and behave in similar ways, yet belong to three far-flung branches of the passerine family tree; they are as unrelated as it is possible to be while remaining Passeriformes.[lower-alpha 1]

Advances in molecular biology and improved paleobiogeographical data gradually are revealing a clearer picture of passerine origins and evolution that reconciles molecular affinities, the constraints of morphology, and the specifics of the fossil record.[15][16] The first passerines are now thought to have evolved in the Southern Hemisphere in the late Paleocene or early Eocene, around 50 million years ago.[5][16]

The initial split was between the New Zealand wrens (Acanthisittidae) and all other passerines (Eupasseres), and the second split involved the Tyranni (suboscines) and the Passeri (oscines or songbirds).[3] The final separation of Gondwanan continents caused the split of Eupasseres into the Tyranni in South America and the Passeri in the Australian continent.[2][16] Passeri experienced a great radiation of forms out of Australia. A major branch of the Passeri, the parvorder Passerida, expanded deep into Eurasia and Africa, where a further explosive radiation of new lineages occurred.[16] This eventually led to three major Passerida lineages comprising about 4,000 species, which in addition to the Corvida and numerous minor lineages make up songbird diversity today. Extensive biogeographical mixing happens, with northern forms returning to the south, southern forms moving north, and so on.[3]

Earliest passerines

Male superb lyrebird (Menura novaehollandiae): This very primitive songbird shows strong sexual dimorphism, with a peculiarly apomorphic display of plumage in males.

Perching bird osteology, especially of the limb bones, is rather diagnostic.[17][18][19] However, the early fossil record is poor because passerines are relatively small, and their delicate bones do not preserve well. Queensland Museum specimens F20688 (carpometacarpus) and F24685 (tibiotarsus) from Murgon, Queensland, are fossil bone fragments initially assigned to Passeriformes.[17] However, the material is too fragmentary and their affinities have been questioned.[20] Several more recent fossils from the Oligocene of Europe, such as Wieslochia, Jamna, Resoviaornis, and Crosnoornis,[21] are more complete and definitely represent early passeriforms, although their exact affinities are not known.

From the Bathans Formation at the Manuherikia River in Otago, New Zealand, MNZ S42815 (a distal right tarsometatarsus of a tui-sized bird) and several bones of at least one species of saddleback-sized bird have recently been described. These date from the Early to Middle Miocene (Awamoan to Lillburnian, 19–16 mya).[22]

Early European passerines

Wieslochia fossil

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)
• Resoviaornis (Early Oligocene of Wola Rafałowska, Poland)
• Jamna (Early Oligocene of Jamna Dolna, Poland)
• Winnicavis (Early Oligocene of Lower Silesian Voivodeship, Poland)
• Crosnoornis (Early Oligocene of Poland)
• Passeriformes gen. et sp. indet. (Early Oligocene of Luberon, France) – suboscine or basal[lower-alpha 2]
• Passeriformes gen. et spp. indet. (Late Oligocene of France) – several suboscine and oscine taxa[24][19]
• Passeriformes gen. et spp. indet. (Middle Miocene of France and Germany) – basal?[lower-alpha 3]
• Passeriformes gen. et spp. indet. (Sajóvölgyi Middle Miocene of Mátraszőlős, Hungary) – at least 2 taxa, possibly 3; at least one probably Oscines.[lower-alpha 4]
• Passeriformes gen. et sp. indet. (Middle Miocene of Felsőtárkány, Hungary) – oscine?[lower-alpha 5]
• Passeriformes gen. et sp. indet. (Late Miocene of Polgárdi, Hungary) – Sylvioidea (Sylviidae? Cettiidae?)[27]

That suboscines expanded much beyond their region of origin is proven by several fossils from Germany such as a presumed broadbill (Eurylaimidae) humerus fragment from the Early Miocene (roughly 20 mya) of Wintershof, Germany, the Late Oligocene carpometacarpus from France listed above, and Wieslochia, among others.[18][16] Extant Passeri super-families were quite distinct by that time and are known since about 12–13 mya when modern genera were present in the corvoidean and basal songbirds. The modern diversity of Passerida genera is known mostly from the Late Miocene onward and into the Pliocene (about 10–2 mya). Pleistocene and early Holocene lagerstätten (<1.8 mya) yield numerous extant species, and many yield almost nothing but extant species or their chronospecies and paleosubspecies.

The Passeriformes is currently divided into three suborders: Acanthisitti (New Zealand wrens), Tyranni, (suboscines) and Passeri (oscines or songbirds). The Passeri is now subdivided into two major groups recognized now as Corvides and Passerida respectively containing the large superfamilies Corvoidea and Meliphagoidea, as well as minor lineages, and the superfamilies Sylvioidea, Muscicapoidea, and Passeroidea but this arrangement has been found to be oversimplified. Since the mid-2000s, studies have investigated the phylogeny of the Passeriformes and found that many families from Australasia traditionally included in the Corvoidea actually represent more basal lineages within oscines. Likewise, the traditional three-superfamily arrangement within the Passeri has turned out to be far more complex and will require changes in classification.

Major "wastebin" families such as the Old World warblers and Old World babblers have turned out to be paraphyletic and are being rearranged. Several taxa turned out to represent highly distinct lineages, so new families had to be established, some of them – like the stitchbird of New Zealand and the Eurasian bearded reedling – monotypic with only one living species.[31] 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 10 species today 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, though they might be fairly close to some little-studied tropical Asian groups. Nuthatches, wrens, and their closest relatives are currently grouped in a distinct super-family Certhioidea.

New Zealand rock wren (Xenicus gilviventris), one of the two surviving species of suborder Acanthisitti

This list is in taxonomic order, placing related families next to one another. The families listed are those recognised by the International Ornithologists' Union (IOC).[1] The order and the division into infraorders, parvorders, and superfamilies follows the phylogenetic analysis published by Carl Oliveros and colleagues in 2019.[30][lower-alpha 7] The relationships between the families in the suborder Tyranni (suboscines) were all well determined but some of the nodes in Passeri (oscines or songbirds) were unclear owing to the rapid splitting of the lineages.[30]

Suborder Acanthisitti

• Acanthisittidae: New Zealand wrens

Javan banded pitta (Hydrornis guajanus), an Old World suboscine.

Andean cock-of-the-rock (Rupicola peruvianus) a New World suboscine

Suborder Passeri (oscines or songbirds)

Male stitchbird or hihi (Notiomystis cincta) showing convergence with honeyeaters

• Atrichornithidae: scrub-birds
• Menuridae: lyrebirds
• Climacteridae: Australian treecreepers
• Ptilonorhynchidae: bowerbirds
• Maluridae: fairywrens, emu-wrens and grasswrens
• Dasyornithidae: bristlebirds
• Pardalotidae: pardalotes
• Acanthizidae: scrubwrens, thornbills, and gerygones
• Meliphagidae: honeyeaters
• Pomatostomidae: pseudo-babblers
• Orthonychidae: logrunners

Male regent bowerbird (Sericulus chrysocephalus, Ptilonorhynchidae)

• Infraorder Corvides – previously known as the parvorder Corvida[33]

• Cinclosomatidae: jewel-babblers, quail-thrushes
• Campephagidae: cuckooshrikes and trillers
• Mohouidae: whiteheads
• Neosittidae: sittellas

• Superfamily Orioloidea[lower-alpha 8]

• Psophodidae: whipbirds
• Eulacestomatidae: wattled ploughbill
• Falcunculidae: shriketit
• Oreoicidae: Australo-Papuan bellbirds
• Paramythiidae: painted berrypeckers
• Vireonidae: vireos
• Pachycephalidae: whistlers
• Oriolidae: Old World orioles and figbirds

• Superfamily Malaconotoidea[lower-alpha 9]

Tiny goldcrest (Regulus regulus) belongs to a minor but highly distinct lineage of Passeri

• Machaerirhynchidae: boatbills
• Artamidae: woodswallows, butcherbirds, currawongs, and Australian magpie
• Rhagologidae: mottled berryhunter
• Malaconotidae: puffback shrikes, bush shrikes, tchagras, and boubous
• Pityriaseidae: bristlehead
• Aegithinidae: ioras
• Platysteiridae: wattle-eyes and batises
• Vangidae: vangas

• Superfamily Corvoidea[lower-alpha 10]

• Rhipiduridae: fantails
• Dicruridae: drongos
• Monarchidae: monarch flycatchers
• Ifritidae: blue-capped ifrit
• Paradisaeidae: birds-of-paradise
• Corcoracidae: white-winged chough and apostlebird
• Melampittidae: melampittas
• Laniidae: shrikes
• Platylophidae: jayshrike
• Corvidae: crows, ravens, and jays

Reed warblers, such as this Blyth's reed warbler (Acrocephalus dumetorum), are now in the Acrocephalidae

• Infraorder Passerides – previously known as the parvorder Passerida[33]

• Cnemophilidae: satinbirds
• Melanocharitidae: berrypeckers and longbills
• Callaeidae: New Zealand wattlebirds
• Notiomystidae: stitchbird
• Petroicidae: Australian robins
• Eupetidae: rail-babbler
• Picathartidae: rockfowl
• Chaetopidae: rock-jumpers

Eurasian blue tit (Cyanistes caeruleus) and its relatives stand well apart from the rest of the Sylvioidea sensu lato

• Parvorder Sylviida[lower-alpha 11] – previously known as the superfamily Sylviodea[33]

• Hyliotidae: hyliotas
• Stenostiridae: fairy flycatchers
• Paridae: tits, chickadees and titmice
• Remizidae: penduline tits
• Panuridae: bearded reedling
• Alaudidae: larks
• Nicatoridae: nicators
• Macrosphenidae: crombecs and African warblers
• Cisticolidae: cisticolas and allies

Brown-headed nuthatch (Sitta pusilla), nuthatches can climb downwards head-first

• Superfamily Locustelloidea

• Acrocephalidae: reed warblers, Grauer's warbler and allies
• Locustellidae: grassbirds and allies
• Donacobiidae: black-capped donacobius
• Bernieridae: Malagasy warblers

—

• Pnoepygidae: wren-babblers
• Hirundinidae: swallows and martins

Hermit thrush (Catharus guttatus), like many Muscicapoidea a stout and cryptic bird with complex vocalizations.

• Superfamily Sylvioidea

• Pycnonotidae: bulbuls
• Sylviidae: sylviid babblers
• Paradoxornithidae: parrotbills and myzornis
• Zosteropidae: white-eyes
• Timaliidae: tree babblers
• Leiothrichidae: laughingthrushes and allies
• Alcippeidae: Alcippe fulvettas
• Pellorneidae: ground babblers

Like these male (right) and female Gouldian finches (Erythrura gouldiae), many Passeroidea are very colorful

• Superfamily Aegithaloidea

• Phylloscopidae: leaf-warblers and allies
• Hyliidae: hylias
• Aegithalidae: long-tailed tits or bushtits
• Scotocercidae: streaked scrub warbler
• Cettiidae: Cettia bush warblers and allies
• Erythrocercidae: yellow flycatchers

Lesser striped swallow (Cecropis abyssinica), showing some apomorphies of its ancient yet highly advanced lineage.

• Parvorder Muscicapida – previously known as the superfamily Muscicapoidea[33]

• Superfamily Bombycilloidea

• Dulidae: palmchat
• Bombycillidae: waxwings
• Ptiliogonatidae: silky flycatchers
• Hylocitreidae: hylocitrea
• Hypocoliidae: hypocolius
• †Mohoidae: oos

Gran Canaria blue chaffinch (male)

• Superfamily Muscicapoidea

• Elachuridae: spotted elachura
• Cinclidae: dippers
• Muscicapidae: Old World flycatchers and chats
• Turdidae: thrushes and allies
• Buphagidae: oxpeckers
• Sturnidae: starlings and rhabdornis
• Mimidae: mockingbirds and thrashers

—

• Regulidae: goldcrests and kinglets

• Superfamily Certhioidea

• Tichodromidae: wallcreeper
• Sittidae: nuthatches
• Certhiidae: treecreepers
• Polioptilidae: gnatcatchers
• Troglodytidae: wrens

• Parvorder Passerida – previously known as the superfamily Passeroidea[33]

• Promeropidae: sugarbirds
• Modulatricidae: dapple-throat and allies
• Nectariniidae: sunbirds
• Dicaeidae: flowerpeckers
• Chloropseidae: leafbirds
• Irenidae: fairy-bluebirds
• Peucedramidae: olive warbler
• Urocynchramidae: Przewalski's finch
• Ploceidae: weavers
• Viduidae: indigobirds and whydahs
• Estrildidae: waxbills, munias and allies
• Prunellidae: accentors
• Passeridae: Old World sparrows and snowfinches
• Motacillidae: wagtails and pipits
• Fringillidae: finches and euphonias

• Superfamily Emberizoidea – previously known as the New World nine-primaried oscines[34][lower-alpha 12]

• Rhodinocichlidae: rosy thrush-tanager
• Calcariidae: longspurs and snow buntings
• Emberizidae: buntings
• Cardinalidae: cardinals
• Mitrospingidae: mitrospingid tanagers
• Thraupidae: tanagers and allies
• Passerellidae: New World sparrows, bush tanagers
• Parulidae: New World warblers
• Icteriidae: yellow-breasted chat
• Icteridae: grackles, New World blackbirds, and New World orioles
• Calyptophilidae: chat-tanagers
• Zeledoniidae: wrenthrush
• Teretistridae: Cuban warblers[lower-alpha 13]
• Nesospingidae: Puerto Rican tanager
• Spindalidae: spindalises
• Phaenicophilidae: Hispaniolan tanagers

The Wikibook Dichotomous Key has a page on the topic of: Passeriformes

• The dictionary definition of passerine at Wiktionary
• Media related to Passeriformes at Wikimedia Commons
• Data related to Passeriformes at Wikispecies