Passerine

A **passerine** is a small or medium-sized bird of the order **Passeriformes**, which includes more than half of all bird species. They are perching birds. Most of them are small in size, and most can sing very well. Their main suborder is the Passeri, the songbirds.

## Adaptations

The passerines have a number of adaptations which, taken together, have made them highly successful, with many species around the world.

1. 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.
1. All passerine chicks are born in an undeveloped state (altricial): they need parental help. Their eyes are closed, and they are bald, with little or no down. They cannot leave the nest, and must be fed by the parents. The advantage of this is that their brains grow larger during the fledgling stage. In birds which leave the nest early, their brains depend mainly on material in the egg. Passerines have significantly large brains compared to body size, and many passerines are comparatively intelligent.
1. The use of song for communication. This is the most obvious adaptation.
1. Almost all passerines have 12 tail feathers. This is a basal trait, a feature inherited from their past. It leads biologists to think this large group originally had one common ancestor.

## Evolution

Evidence on their evolution comes from comparative anatomy, the fossil record and molecular biology.

It is thought that the first passerines evolved in the southern continent of Gondwana in the Palaeogene. This might have taken place around the Upper Palaeocene some 60–55 mya. The latest opinion on passerine evolution is that the passerines originated on the Australian landmass ∼47 mya.

The early fossil record is poor because the first Passeriformes were on the small side, and their delicate bones did not preserve well. Two specimens from Queensland, Australia are fossil bone fragments clearly recognizable as passeriform. They are two species of about 10 and 20 cm in overall length. This proves that some 55 mya, barely into the early Eocene, early perching birds were recognizably distinct. It also suggests that the origin of this great order of birds was in the southern continent.

## Taxonomy

There are three sub-orders: _Acanthisitti_, _Tyranni_ and _Passeri_. There are only two bird species in the sub-order Acanthisitti. They are known as New Zealand wrens. The sub-order Tyranni are also known as the **suboscines**. Many of these birds are found in tropical areas. The sub-order Passeri has the most bird species. They are also known as the **oscines**.

### Suborder Acanthisitti

- Acanthisittidae: New Zealand "wrens"

### Suborder Tyranni

Suboscines
- **Infraorder Eurylaimides** broadbills and allies
- **Infraorder Tyrannides** - New World suboscines

### Suborder Passeri

Songbirds or oscines
- **Basal Passeri** – the oldest 'true' song birds. They live in Australia.
    - Menuridae: lyrebirds
    - Atrichornithidae:  scrub-birds
- **Superfamily Meliphagoidea** – mainly insectivores and nectarivores, distribution centered on Australo-Melanesian region extending into surroundings, notably the Pacific.
- **Superfamily Corvida** – a highly diverse group of global distribution, but most plentiful in the Australasian region and surroundings. The oldest truly globally successful group of passerines, they include among them what may well be the most intelligent and the most spectacular of the order.
    - Melanocharitidae:  berrypeckers and longbills.
    - Callaeidae: New Zealand wattlebirds
    - Stitchbirds
    - Cnemophilidae: satinbirds
    - Neosittidae: sittellas
    - Vireonidae: vireos
    - Campephagidae: cuckoo-shrikes and trillers
    - Pachycephalidae: whistlers and allies
    - Oriolidae: orioles and figbirds
    - Paramythiidae: tit berrypecker and crested berrypecker.
    - Artamidae: woodswallows, butcherbirds, currawongs and Australian Magpie
    - Malaconotidae: puffback shrikes, bush shrikes, tchagras and boubous
    - Platysteiridae: wattle-eyes
    - Aegithinidae: ioras
    - Pityriaseidae: Bornean bristlehead.
    - Prionopidae: helmetshrikes and woodshrikes
    - Vangidae: vangas
    - Dicruridae: drongos
    - Monarchidae: monarch flycatchers
    - Rhipiduridae: fantails
    - Paradisaeidae: birds of paradise
    - Corcoracidae: white-winged chough and apostlebird
    - Laniidae: shrikes
    - Corvidae: crows, ravens and jays
    - Corvoidea (?)
- **Passeri**
    - Ptilonorhynchoidea: bowerbirds and Australian treecreepers
    - Logrunners and pseudo-babblers
    - Petroicidae: Australian robins
    - Rockfowl, rock-jumpers and rail-babblers
    - Regulidae: kinglets
    - Hyliotas
    - Irenidae: fairy-bluebirds
    - Chloropseidae: leafbirds

#### Infraorder Passerida

- Superfamily Sylvioidea – mostly insectivores, distribution centered on the Indo-Pacific region. Few occur in the Australian region and fewer still in the Americas. Usually sleek and drab birds, few have pronounced sexual dimorphism.
    - Alaudidae: larks
    - Hirundinidae:  swallows and martins
    - Phylloscopidae: leaf-warblers and allies.
    - Aegithalidae: long-tailed tits or bushtits
    - Cettiidae: ground-warblers and allies
    - Megaluridae: grass-warblers and allies
    - "Bernieridae": Malagasy warblers. A new family.
    - Acrocephalidae: marsh- and tree-warblers
    - Pycnonotidae: bulbuls
    - Cisticolidae: cisticolas and allies
    - Sylviidae: "true warblers" and parrotbills.
    - Zosteropidae: white-eyes
    - Timaliidae: (Old World) babblers.
    - Sylvioidea (?)
- Superfamily Muscicapoidea – mostly insectivores, near-global distribution centered on Old World tropics. One family endemic to Americas. Nearly absent (except introductions) from the Australian region. Usually rather stocky for their size, most are quite dark and dull though Sturnidae are commonly iridescent and/or colorful. Sexual dimorphism often absent, sometimes pronounced.
    - Cinclidae: dippers
    - Muscicapidae: Old World flycatchers and chats.
    - Turdidae: thrushes and allies.
    - Buphagidae: oxpeckers. Formerly usually included in Sturnidae.
    - Sturnidae: starlings and possibly Philippine creepers.
    - Mimidae: mockingbirds and thrashers

- Superfamily Certhioidea - wrens and allies
    - Sittidae:  nuthatches
    - Tichodromadidae: wallcreepers
    - Certhiidae:  treecreepers
    - Salpornithidae: spotted creeper
    - Troglodytidae: wrens
    - Polioptilidae: gnatcatchers
- Superfamily Passeroidea – mostly herbivores including many seed-eaters, near-global distribution centered on Palearctic and Americas. Includes the Nine-primaried oscines (probably a subclade). A very high proportion of colorful and highly sexually dimorphic forms.
    - Passeridae: true sparrows
    - Prunellidae: accentors
    - Motacillidae: wagtails and pipits
    - Urocynchramidae Przewalski's finch
    - Estrildidae:  estrildid finches (waxbills, munias, etc.)
    - Ploceidae: weavers
    - Viduidae: indigobirds and whydahs
    - Nine-primaried oscines:
        - Peucedramidae: olive warbler
        - Fringillidae: true finches and Hawaiian honeycreepers
        - Icteridae: grackles, New World blackbirds, and New World orioles
        - Parulidae: New World warblers
        - Thraupidae: tanagers and allies
        - Cardinalidae: cardinals
        - Emberizidae: buntings and American sparrows
    - Coerebidae: bananaquit
- Passerida: (?)
    - _Panurus_: bearded reedling ("bearded "tit")
    - _Paroidea_: titmice and allies
        - Paridae: tits, chickadees and titmice
        - Remizidae: penduline tits
        - Stenostiridae: stenostirids ("flycatcher-tits")
    - "Bombycilloidea" waxwings and allies
        - Bombycillidae: waxwings
        - Dulidae: palmchat
        - Ptilogonatidae: silky flycatchers
        - Hypocoliidae: _Hypocolius_
        - Mohoidae
    - "Dicaeoidea" sunbirds and flowerpeckers
        - Nectariniidae: sunbirds
        - Dicaeidae: flowerpeckers
    - Promeropidae: sugarbirds