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 some estimates, modern birds (Neornithes) evolved in the Late Cretaceous or between the Early and Late Cretaceous (100 Ma) 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...)
Bird netting or anti-bird netting is a form of bird pest control. It is a net used to prevent birds from reaching certain areas.
Bird protection netting comes in a variety of shapes and forms, The most common is a small mesh (1 or 2 cm squares) either extruded and bi-oriented polypropylene or woven polyethylene. (Full article...)
Neognathae (/niˈɒɡnəθiː/; from Ancient Greek νέος (néos) 'new, young' and γνάθος (gnáthos) 'jaw') is an infraclass of birds, called neognaths, within the class Aves of the clade Archosauria. Neognathae includes the majority of living birds; the exceptions being the tinamous and the flightless ratites, which belong instead to the sister taxon Palaeognathae. There are nearly 10,000 living species of neognaths.
The earliest fossils are known from the very end of the Cretaceous with the oldest known members being Teviornis and Vegavis, but molecular clocks suggest that neognaths originated sometime in the first half of the Late Cretaceous, about 90 million years ago. Since then, they have undergone adaptive radiation, producing the diversity of form, function, and behavior that exists today. Neognathae includes the order Passeriformes (perching birds), one of the largest orders of land vertebrates, containing some 60% of living birds. Passeriformes is twice as species-rich as Rodentia and about five times as species-rich as Chiroptera (bats), which are the two largest orders of mammals. Neognathae also contains some very small orders, often birds of unclear relationships like the hoatzin.
The neognaths have fused metacarpals, an elongate third finger, and 13 or fewer vertebrae. They differ from the Palaeognathae in features like the structure of their jawbones. Neognathae means "new jaws", but it seems that the supposedly "more ancient" paleognath jaws are among the few apomorphic (more derived) features of the palaeognaths, meaning that the respective jaw structure of these groups is not informative in terms of comparative evolution. However, a neognath-like palate is also present in ornithuran birds like Ichthyornis. (Full article...)
Anatomy: Anatomy • Skeleton • Flight • Eggs • Feathers • Plumage
Evolution and extinction: Evolution • Archaeopteryx • Hybridisation • Late Quaternary prehistoric birds • Fossils • Taxonomy • Extinction
Behaviour: Singing • Intelligence • Migration • Reproduction • Nesting • Incubation • Brood parasites
Bird orders: Struthioniformes • Tinamiformes • Anseriformes • Accipitriformes • Galliformes • Gaviiformes • Podicipediformes • Procellariiformes • Sphenisciformes • Pelecaniformes • Ciconiiformes • Phoenicopteriformes • Falconiformes • Gruiformes • Charadriiformes • Pteroclidiformes • Columbiformes • Psittaciformes • Cuculiformes • Strigiformes • Caprimulgiformes • Apodiformes • Coraciiformes • Piciformes • Trogoniformes • Coliiformes • Passeriformes
Bird lists: Families and orders • Lists by region
Birds and humans: Ringing • Ornithology • Bird collections • Birdwatching • Birdfeeding • Conservation • Aviculture
“ | Have you ever observed a humming-bird moving about in an aerial dance among the flowers - a living prismatic gem.... it is a creature of such fairy-like loveliness as to mock all description. | ” |
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.
The hyperpallium (formerly called the hyperstriatum or the wulst) is the destination for lemnothalamic projections in birds. The projections as well as the granular cells at the destination of the lemnothalamic projections to the hyperpallium are similar in morphology, electrophysiology, retinotopic organization, and columnar organization to the striate cortex in mammals. These avian granular cells are thought to have evolved independently in birds, as they do not appear in reptiles.
The projections originate in the dorsal lateral geniculate nucleus and target three layers in the hyperpallium: the hyperpallium intercalatum, the hyperpallium densocellularis, and the nucleus interstitialis hyperpalii apicalis, with the densest projections being to the later two layers. (Full article...)
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Class Aves, divided into superorders, orders, suborders (where indicated), and families. | ||||
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