Portal:Birds

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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 over 11,000 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. The study of birds is called ornithology.

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 during the Late Jurassic. According to recent estimates, modern birds (Neornithes) evolved in the Late Cretaceous and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 million years ago, 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 pet grey parrot displaying signs of extensive feather-plucking.

Abnormal behavior of birds in captivity has been found to occur among both domesticated and wild birds. Abnormal behavior can be defined in several ways. Statistically, 'abnormal' is when the occurrence, frequency or intensity of a behaviour varies statistically significantly, either more or less, from the normal value. This means that theoretically, almost any behaviour could become 'abnormal' in an individual. Less formally, 'abnormal' includes any activity judged to be outside the normal behaviour pattern for captive birds of that particular class or age. For example, running rather than flying may be a normal behaviour and regularly observed in one species, however, in another species it might be normal but becomes 'abnormal' if it reaches a high frequency, or in another species it is rarely observed and any incidence is considered 'abnormal'. This article does not include 'one-off' behaviours performed by individual birds that might be considered abnormal for that individual, unless these are performed repeatedly by other individuals in the species and are recognised as part of the ethogram of that species.

Most abnormal behaviours can be categorised collectively (e.g., eliminative, ingestive, stereotypies), however, many abnormal behaviours fall debatably into several of these categories and categorisation is therefore not attempted in this article. Abnormal behaviours here are considered to be related to captive housing but may also be due to medical conditions. The article does not include behaviours in birds that are genetically modified to express abnormal behaviour. (Full article...)

Selected taxon

Columbidae (/kəˈlʌmbɪd/ kə-LUM-bih-dee) is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with short necks and short slender bills that in some species feature fleshy ceres. They primarily feed on plants, and can be taxonomically divided amongst granivores, that feed mostly on the ground on seeds, and frugivores, that feed mostly on fruits, from branches. The family occurs worldwide, often in close proximity with humans, but the greatest variety is in the Indomalayan and Australasian realms.

Columbidae contains 344 species divided into 50 genera. 59 species are listed as threatened, and thirteen are extinct, including the dodo, an island bird, and the passenger pigeon, the only bird species not restricted to a small island to go extinct in modern times, even though its flocks were counted in the billions.

Mostly only by English speakers, the smaller species tend to be called "doves", and the larger ones "pigeons", although the distinction is not consistent, and there is no scientific separation between them. Historically, the common names for these birds involve a great deal of variation. The bird most commonly referred to as "pigeon" is the domestic pigeon, or rock dove, which is common in many cities as the feral pigeon. (Full article...)
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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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The cnemial crest is a crestlike prominence located at the front side of the head of the tibiotarsus or tibia in the legs of many mammals and reptiles (including birds and other dinosaurs). The main extensor muscle of the thigh is attached to this ridge. (Full article...)
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Selected species

California condor
The California condor, Gymnogyps californianus, is a species of North American bird in the New World vulture family Cathartidae. Currently, this condor inhabits only the western coastal mountains of the United States, Baja California, and the Grand Canyon. It is the only surviving member of the genus Gymnogyps, though fossil members are known. It is a large, black vulture with patches of white on the underside of the wings and a largely bald head with skin color ranging from yellowish to a glowing red, depending on the bird’s mood. It has the largest wingspan of any bird found in North America and is one of the heaviest. The condor is a scavenger and eats large amounts of carrion. Condor numbers dramatically declined in the 20th century. A conservation plan was put in place by the United States government that led to the capture of all the remaining wild condors in 1987. Beginning in 1991, condors have been reintroduced into the wild. The California condor is one of the world's rarest bird species. As of 2005, there were only 273 individuals including 127 in the wild.


Did you know

  • ...that sexual size dimorphism in the brown songlark is among the most pronounced in any bird, with males as much as 2.3 times heavier than females?
  • ...that rufous whistler birds, unlike all other whistler birds, never forage on the ground but high up in trees or other high places?
  • ...that the bill of the magpie duck (pictured) becomes green as the bird gets older, and its black crown may go completely white?

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More outstanding tasks at the project's cleanup listing, Category:Birds articles needing attention, and Wikipedia:WikiProject Birds/Todo.

Taxonomy of Aves

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Sources

  1. ^ Damon, S.F.; Eaves, M. (1988). A Blake Dictionary: The Ideas and Symbols of William Blake. Reference: Literary Criticism. Brown University Press. p. 112. ISBN 978-0-87451-436-0. Retrieved February 7, 2020.
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