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Portal:Birds

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The Birds Portal

Birds are a group of warm-blooded vertebrates constituting the class Aves (Latin: [ˈaveːs]), 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 and they are split into 44 orders. More than half 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-ornithuran dinosaurs.

Many social species preserve knowledge across generations (culture). Birds are social, communicating with visual signals, calls, and songs, and participating in such behaviour 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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Migration of cranes

Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal activity or even survival difficult or near impossible. In some cases "winter" is characterized not necessarily by cold but by dry conditions; passing through such periods could likewise be called overwintering.

Hibernation and migration are the two major ways in which overwintering is accomplished. Animals may also go into a state of reduced physiological activity known as torpor. (Full article...)

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Sagittarius serpentarius

Sagittariidae is a family of raptor with one living species—the secretarybird (Sagittarius serpentarius) native to Africa—and a few fossil taxa.

This single extant species has affected the fossil record of the group by ‘pulling’ the temporal range of the family to the present, an artifact called the Pull of the recent.[relevant?]

German naturalists Otto Finsch and Gustav Hartlaub established the taxon name as a subfamily—Sagittariinae—in 1870. Although their term postdated Gypogeranidae of Vigors (1825) and Serpentariidae of Selys Longchamps (1842), the genus name Sagittarius (described in 1783) had priority over Gypogeranus Illiger, 1811 and Serpentarius Cuvier, 1798. (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.

WikiProjects

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Sea turtles excrete salts through tear ducts. "Crying" is visible when out of water.

The salt gland is an organ for excreting excess salts. It is found in the cartilaginous fishes subclass elasmobranchii (sharks, rays, and skates), seabirds, and some reptiles. Salt glands can be found in the rectum of sharks. Birds and reptiles have salt glands located in or on the skull, usually in the eyes, nose, or mouth. These glands are lobed containing many secretory tubules which radiate outward from the excretory canal at the center. Secretory tubules are lined with a single layer of epithelial cells. The diameter and length of these glands vary depending on the salt uptake of the species.

Salt glands maintain salt balance and allow marine vertebrates to drink seawater. Active transport via sodium–potassium pump, found on the basolateral membrane, moves salt from the blood into the gland, where it is excreted as a concentrated solution. (Full article...)

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Kākāpō drawing
The kākāpō (Māori: kākāpō, meaning "night parrot", Strigops habroptilus), also called owl parrot, is a species of nocturnal parrot with finely blotched yellow-green plumage endemic to New Zealand. It has a distinct facial disc of sensory, vibrissa-like feathers, a large grey beak, short legs, large feet, and wings and a tail of relatively short length. A certain combination of traits makes it unique among its kind—it is the world's only flightless parrot, the heaviest parrot, nocturnal, herbivorous, it sports visible sexual dimorphism in body size, has a low basal metabolic rate, no male parental care, and is the only parrot to have a polygynous lek breeding system. It is also possibly one of the world's longest-living birds. Its anatomy typifies the tendency of bird evolution on oceanic islands with few predators and abundant food: accretion of thermodynamic efficiency at the expense of flight abilities, reduced wing muscles, a diminished keel on the sternum and a generally robust physique. Kākāpō are critically endangered; there are only 244 (as of 2024).[2] The ancestral kākāpō migrated to the islands of New Zealand in prehistory; in the absence of mammalian predators, it lost the ability to fly. Because of Polynesian and European colonisation and the introduction of predators such as cats, rats, and stoats, most of the kākāpō were wiped out. Conservation efforts began in the 1890s, but they were not very successful until the implementation of the Kakapo Recovery Plan in the 1980s. As of November 2005, surviving kākāpō are kept on four predator-free islands, Maud, Chalky (Te Kakahu), Codfish (Whenua Hou) and Anchor islands, where they are closely monitored. Two large Fiordland islands, Resolution and Secretary, have been the subject of large-scale ecological restoration activities to prepare self-sustaining ecosystems with suitable habitat for the kākāpō. The conservation of the kākāpō has made the species well known. Many books and documentaries detailing the plight of the kākāpō have been produced in recent years. The kākāpō, like many other bird species, has historically been important to the Māori, the indigenous people of New Zealand, appearing in many of the traditional legends and folklore.


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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Taxonomy of Aves

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Sources

  1. ^ Blake, William (1996). Davis, Mike; Pound, Alan (eds.). Blake: Selected Poems. Oxford, UK: Heinemann Educational Publishers. p. 101. ISBN 0-435150-82-0.
  2. ^ "Kākāpō Recovery". Department of Conservation. New Zealand. Retrieved 26 September 2024
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