Passerine

Passerine
A passerine is any bird of the order Passeriformes (from Latin 'sparrow' and '-shaped'), which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their toes (three pointing forward and one back), which facilitates perching.
With more than 140 families and some 6,500 identified species, Passeriformes is the largest order of birds and among the most diverse clades of terrestrial vertebrates, representing 60% of birds. Passerines are divided into three clades: Acanthisitti (New Zealand wrens), Tyranni (mostly-South American suboscines), and Passeri (oscines or songbirds). The passerines contain several groups of brood parasites such as the viduas, cuckoo-finches, and the cowbirds. Most passerines are omnivorous, though shrikes are carnivorous, and others are insectivorous.
The terms "passerine" and "Passeriformes" are derived from the scientific name of the house sparrow, Passer domesticus, and ultimately from the Latin term passer, which refers to sparrows and similar small birds.
Description
The order is divided into three suborders, Tyranni (suboscines), Passeri (oscines or songbirds), and the basal Acanthisitti. 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. The New Zealand wrens are tiny birds restricted to New Zealand, at least in modern times; they were long placed in Passeri.
Most passerines are smaller than typical members of other avian orders. The heaviest and altogether largest passerines are the thick-billed raven and the larger races of common raven, each exceeding and . 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 and .
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 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.
Most passerine birds have 12 tail feathers but the superb lyrebird has 16, 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. Extremely long tails used as sexual ornaments are shown by species in different families. A well-known example is the long-tailed widowbird.
Eggs and nests
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.
Origin and evolution
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.
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. 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.
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). The final separation of Gondwanan continents caused the split of Eupasseres into the Tyranni in South America and the Passeri in the Australian continent. 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. 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.
Fossil record
Earliest passerines
Perching bird osteology, especially of the limb bones, is rather diagnostic. 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. However, the material is too fragmentary and their affinities have been questioned. Several more recent fossils from the Oligocene of Europe, such as Wieslochia, Jamna, Resoviaornis, and Crosnoornis, 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).
Early European passerines
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
Passeriformes gen. et spp. indet. (Late Oligocene of France) – several suboscine and oscine taxa
Passeriformes gen. et spp. indet. (Middle Miocene of France and Germany) – basal?
Passeriformes gen. et spp. indet. (Sajóvölgyi Middle Miocene of Mátraszőlős, Hungary) – at least 2 taxa, possibly 3; at least one probably Oscines.
Passeriformes gen. et sp. indet. (Middle Miocene of Felsőtárkány, Hungary) – oscine?
Passeriformes gen. et sp. indet. (Late Miocene of Polgárdi, Hungary) – Sylvioidea (Sylviidae? Cettiidae?)
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. 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.
American fossils
In the Americas, the fossil record is more scant before the Pleistocene, from which several still-existing suboscine families are documented. Apart from the indeterminable MACN-SC-1411 (Pinturas Early/Middle Miocene of Santa Cruz Province, Argentina), an extinct lineage of perching birds has been described from the Late Miocene of California, United States: the Palaeoscinidae with the single genus Palaeoscinis. "Palaeostruthus" eurius (Pliocene of Florida) probably belongs to an extant family, most likely passeroidean.
Systematics and taxonomy
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. 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.
Taxonomic list of Passeriformes families
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). The order and the division into infraorders, parvorders, and superfamilies follows the phylogenetic analysis published by Carl Oliveros and colleagues in 2019. 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.
Suborder Acanthisitti
Acanthisittidae: New Zealand wrens
Suborder Tyranni (suboscines)
Infraorder Eurylaimides: Old World suboscines
Infraorder Tyrannides: New World suboscines
Parvorder Furnariida
Parvorder Tyrannida
Suborder Passeri (oscines or songbirds)
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
Infraorder Corvides – previously known as the parvorder Corvida
Cinclosomatidae: jewel-babblers, quail-thrushes
Campephagidae: cuckooshrikes and trillers
Mohouidae: whiteheads
Neosittidae: sittellas
Superfamily Orioloidea
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
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
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
Infraorder Passerides – previously known as the parvorder Passerida
Cnemophilidae: satinbirds
Melanocharitidae: berrypeckers and longbills
Callaeidae: New Zealand wattlebirds
Notiomystidae: stitchbird
Petroicidae: Australian robins
Eupetidae: rail-babbler
Picathartidae: rockfowl
Chaetopidae: rock-jumpers
Parvorder Sylviida – previously known as the superfamily Sylviodea
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
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
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
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
Parvorder Muscicapida – previously known as the superfamily Muscicapoidea
Superfamily Bombycilloidea
Dulidae: palmchat
Bombycillidae: waxwings
Ptiliogonatidae: silky flycatchers
Hylocitreidae: hylocitrea
Hypocoliidae: hypocolius
†Mohoidae: oos
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
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
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
Nesospingidae: Puerto Rican tanager
Spindalidae: spindalises
Phaenicophilidae: Hispaniolan tanagers
Phylogeny
Relationships between living Passeriformes families based on the phylogenetic analysis of Oliveros et al (2019). Some terminals have been renamed to reflect families recognised by the IOC but not in that study. The IOC families Alcippeidae and Teretistridae were not sampled in this study.
Explanatory notes
References
Further reading
Supporting information
External links
Extant Eocene first appearances
Taxa named by Carl Linnaeus