Portal:Birds

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The Birds Portal

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Birds are a group of warm-blooded vertebrates constituting the class Aves (/ˈvz/), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the 5.5 cm (2.2 in) bee hummingbird to the 2.8 m (9 ft 2 in) common ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming.

Birds are feathered theropod dinosaurs and constitute the only known living dinosaurs. Likewise, birds are considered reptiles in the modern cladistic sense of the term, and their closest living relatives are the crocodilians. Birds are descendants of the primitive avialans (whose members include Archaeopteryx) which first appeared about 160 million years ago (mya) in China. According to DNA evidence, modern birds (Neornithes) evolved in the Middle to Late Cretaceous, and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 mya, which killed off the pterosaurs and all non-avian dinosaurs.

Many social species pass on knowledge across generations, which is considered a form of culture. Birds are social, communicating with visual signals, calls, and songs, and participating in such behaviours as cooperative breeding and hunting, flocking, and mobbing of predators. The vast majority of bird species are socially (but not necessarily sexually) monogamous, usually for one breeding season at a time, sometimes for years, and rarely for life. Other species have breeding systems that are polygynous (one male with many females) or, rarely, polyandrous (one female with many males). Birds produce offspring by laying eggs which are fertilised through sexual reproduction. They are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching.

Many species of birds are economically important as food for human consumption and raw material in manufacturing, with domesticated and undomesticated birds being important sources of eggs, meat, and feathers. Songbirds, parrots, and other species are popular as pets. Guano (bird excrement) is harvested for use as a fertiliser. Birds figure throughout human culture. About 120 to 130 species have become extinct due to human activity since the 17th century, and hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry. (Full article...)

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A bird louse is any chewing louse (small, biting insects) of order Phthiraptera which parasitizes warm-blooded animals, especially birds. Bird lice may feed on feathers, skin, or blood. They have no wings, and their biting mouth parts distinguish them from true lice, which suck blood.


Almost all domestic birds are hosts for at least one species of bird louse. Chickens and other poultry are attacked by many kinds of bird lice. Bird lice usually do not cause much harm to a bird unless it is unusually infested as in the case of birds with damaged bills which cannot preen themselves properly. A blood-consuming louse that infests Galápagos Hawks is more numerous on hawks without territories, possibly because those individuals spend more time looking for food and less time preening than hawks with territories. (Full article...)
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Irediparra gallinacea - Comb-crested Jacana.jpg
Comb-crested jacana (Irediparra gallinacea)
The jacanas (sometimes referred to as Jesus birds or lily trotters) are a group of tropical waders in the family Jacanidae. They are found in the tropical regions around the world. They are noted for their elongated toes and toenails that allow them to spread out their weight while foraging on floating or semi-emergent aquatic vegetation. They are also among the rare groups of birds in which females are larger, and several species maintain harems of males in the breeding season with males solely responsible for incubating eggs and taking care of the chicks. (Full article...)
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Free online resources:

There is also Birds of North America, Cornell University's massive project collecting information on every breeding bird in the ABA area. It is available for US$40 a year.

For more sources, including printed sources, see WikiProject Birds.

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Single comb

A comb is a fleshy growth or crest on the top of the head of some gallinaceous birds, such as domestic chickens. The alternative name cockscomb (with several spelling variations) reflects the fact that combs are generally larger on cock birds than on hens. The comb is one of several fleshy protuberances on the heads of chickens, the others being the wattles and earlobes, which collectively are called caruncles. In turkeys, the caruncles are the fleshy nodules on the head and throat.

Chicken combs are most commonly red, but may also be black or dark purple in breeds such as the Silkie or the Sebright. In other species the color may vary from light grey to deep blue or red. (Full article...)
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Two arctic terns
The arctic tern (Sterna paradisaea) is a seabird of the tern family Sternidae. This bird has a circumpolar distribution, breeding colonially in Arctic and sub-Arctic regions of Europe, Asia, and North America (as far south as Brittany and Massachusetts). The species is strongly migratory, seeing two summers each year as it migrates from its northern breeding grounds to the oceans around Antarctica and back each year. This is the longest regular migration by any known animal. Arctic terns are medium-sized birds. They are mainly grey and white plumaged, with a red beak (as long as the head, straight, with pronounced gonys) and feet, white forehead, a black nape and crown (streaked white), and white cheeks. The arctic tern is K-selected, caring for and aggressively defending a small number of young. Parents feed them fish for a considerable time, and help them fly south to winter. Arctic terns are long-lived birds, with many reaching twenty years of age. They eat mainly fish and small marine invertebrates. The species has an estimated one million individuals. Exploitation in the past has reduced this bird's numbers in the southern reaches of its range.


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Taxonomy of Aves

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Sources

  1. ^ Adams, Douglas (1987). Dirk Gently's Holistic Detective Agency. New York, NY, US: Pocket Books. p. 270. ISBN 978-0-671-74672-8.
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