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Passerine

life science Maturity 5-7 Next article →

Passerines are members of the order Passeriformes, a massive group of birds. This order includes more than half of all bird species on Earth.

Goldcrest 1
Goldcrest 1

There are over 6,500 identified species across more than 140 families. This makes Passeriformes one of the largest bird orders. It is also one of the most diverse groups of terrestrial vertebrates. Most passerines make up about 60% of all birds. The name comes from the Latin word for sparrow, specifically from the house sparrow, *Passer domesticus*.

The most famous feature of these birds is their ability to perch. They possess an anisodactyl arrangement of their toes. This means they have three toes pointing forward and one toe, called the hallux, pointing backward. The hallux is long and joins the leg at nearly the same level as the front toes.

Eurasian blue tit Lancashire 2
Eurasian blue tit Lancashire 2

To help them stay on branches, they have a special anatomical adaptation. A tendon runs from the underside of the toes to the muscle behind the tibiotarsus. When the bird bends its leg, this tendon automatically pulls tight. This causes the foot to curl and become stiff. This mechanism allows them to sleep while perching without falling off.

Passerines are categorized into three main suborders based on their evolutionary history. The first is the New Zealand wrens, which are tiny birds restricted to New Zealand. The second is the Tyranni, also known as suboscines. These are primarily found in North and South America and are often called non-singing birds. The third suborder is the Passeri, which includes the songbirds.

Male stitchbird
Male stitchbird

Within the Passeri, there are two major groups: the Corvides and the Passerida. The oscines, or songbirds, have the best control over their syrinx muscles. The syrinx is the vocal organ of birds. This control allows them to produce complex songs. Some, like the lyrebird, are even famous for being accomplished mimics.

Superb lyrbird in scrub
Superb lyrbird in scrub

The evolutionary history of these birds began in the Southern Hemisphere. Scientists believe they originated around 60 million years ago. Their diversification happened as the southern continents separated during the early Eocene. The New Zealand wrens were the first to become isolated in Zealandia. Later, the Tyranni originated in South America, while the Passeri emerged in Australia.

Wieslochia
Wieslochia

About 40 million years ago, the parvorder Passerida dispersed into Eurasia and Africa. This movement led to a massive radiation of new lineages. Today, the three major Passerida lineages include about 4,000 species.

Passerines vary greatly in size and physical form. Most are smaller than birds in other orders. The smallest is the short-tailed pygmy tyrant, measuring only 6.7 cm long and 1.8 g.

Goldcrest 1
Goldcrest 1

In contrast, the thick-billed raven can exceed 1,500 g. Some birds are defined by their tails. Most passerines have 12 tail feathers, but the superb lyrebird has 16.

Superb lyrbird in scrub
Superb lyrbird in scrub

Other species, like the long-tailed widowbird, use extremely long tails as sexual ornaments. Some birds, such as treecreepers, have stiff tail feathers used as props for climbing tree trunks.

Reproduction in passerines involves significant parental investment. Most chicks are altricial, meaning they are born blind, featherless, and helpless. Because of this, they require extensive care from their parents. Most passerines lay colored eggs, which differs from many nonpasserines that lay white eggs. Clutches vary in size based on environment and species. Australian lyrebirds may lay only one egg. In the Northern Hemisphere, hole-nesting species like tits can lay up to a dozen eggs.

GouldianFinches
GouldianFinches

Some species, like those in the family Viduidae, are brood parasites. They do not build their own nests but lay eggs in the nests of other birds.

Understanding passerines helps scientists study how biology and environment interact. For example, research shows that nest construction is a complex task. Building nests with different attachment modes requires different levels of cognitive ability. Furthermore, the fossil record helps clarify how species move across the globe. While small bones do not always preserve well, fossils like *Wieslochia* from the Oligocene provide clues.

Wieslochia
Wieslochia

These findings show how birds expanded from their origins to inhabit almost every corner of the world.

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🖼️ Images & Media (16)
File:PasserinePterylosis.jpg
PasserinePterylosis.jpg
File:Superb lyrbird in scrub.jpg
Superb lyrbird in scrub.jpg
File:Wieslochia.jpg
Wieslochia.jpg
File:Rock wren.jpg
Rock wren.jpg
File:Pitta guajana-20030531B.jpg
Pitta guajana-20030531B.jpg
File:Rupicola peruviana (male) -San Diego Zoo-8.jpg
Rupicola peruviana (male) -San Diego Zoo-8.jpg
File:Male stitchbird.JPG
Male stitchbird.JPG
File:Regentbowerbirdmale.jpg
Regentbowerbirdmale.jpg
File:Goldcrest 1.jpg
Goldcrest 1.jpg
File:Acrocephalus dumetorum.jpg
Acrocephalus dumetorum.jpg
File:Eurasian blue tit Lancashire 2.jpg
Eurasian blue tit Lancashire 2.jpg
File:Brown-headed Nuthatch-27527-4c.jpg
Brown-headed Nuthatch-27527-4c.jpg

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