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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) 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 evolved from 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, but 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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Bird food plants are certain trees, shrubs and herbaceous plants bearing fruits which afford food for birds. These have been discovered by observation, and by the scientific examination of the contents of birds' stomachs. By planting those species, therefore, which have been proved most desirable and that are suited to the climate and soil of the chosen location, birds can be attracted to the vicinity of dwelling houses or to any other desired spot as a copse or shrubbery, or, on the other hand, lured away from valuable orchards, since they appear to like best arid, bitter, sour or aromatic fruits, distasteful to human beings, even better than the cultivated kinds.

Many of these bird-attracting plants are ornamental as well, since many have pretty fruits, red in color and often clinging to their branches far into the winter, furnishing grateful additions to the meager fare of hard-weather birds. (Full article...)
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Brown falcon
(Falco berigora)
The falcons and caracaras are around 60 species of diurnal birds of prey that make up the family Falconidae (representing all extant species in the order Falconiformes). The family is divided into three subfamilies, Herpetotherinae, which includes the laughing falcon and forest falcons, Polyborinae, which includes the caracaras and Spiziapteryx, and Falconinae, the falcons and kestrels (Falco) and falconets (Microhierax). (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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This stylised bird skeleton highlights the keel bone

A keel or carina (plural carinae) in bird anatomy is an extension of the sternum (breastbone) which runs axially along the midline of the sternum and extends outward, perpendicular to the plane of the ribs. The keel provides an anchor to which a bird's wing muscles attach, thereby providing adequate leverage for flight. Not all birds have keels; in particular, some flightless birds lack a keel structure. Without a keel a bird will not be able to fly. Some flightless birds have a keel, such as the penguin; but in the penguin's case, its wings are too small for its body, so flight would require flapping its wings too fast to be practical.

Historically, the presence or absence of a pronounced keel structure was used as a broad classification of birds into two orders: Carinatae (from carina, "keel"), having a pronounced keel; and ratites (from ratis, "raft" – referring to the flatness of the sternum), having a subtle keel structure or lacking one entirely. However, this classification has become disused as evolutionary studies have shown that many flightless birds have evolved from flighted birds. (Full article...)
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Male and female superb fairy-wrens
The superb fairy-wren (Malurus cyaneus), also known as superb blue-wren or colloquially as blue wren, is a passerine bird of the family Maluridae. Sedentary and territorial, it is found across southeastern Australia. The male in breeding plumage has a striking bright blue forehead, ear coverts, mantle and tail with a black mask and black or dark blue throat. Non-breeding males, females and juveniles are predominantly grey-brown in colour. Two subspecies are recognised. Like other fairy-wrens, the superb fairy-wren is notable for several peculiar behavioural characteristics; birds are socially monogamous and sexually promiscuous. Male wrens pluck yellow petals and display them to females as part of a courtship display. The superb fairy-wren can be found in almost any area that has at least a little dense undergrowth for shelter. It has adapted well to the urban environment. The superb fairy-wren mainly eats insects and supplements its diet with seeds.

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Taxonomy of Aves

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  1. ^ Blake, William (1996). Davis, Mike; Pound, Alan (eds.). Blake: Selected Poems. Oxford, UK: Heinemann Educational Publishers. p. 101. ISBN 0-435150-82-0.


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