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 measurement or bird biometrics are approaches to quantify the size of birds in scientific studies. The variation in dimensions and weights across birds is one of the fundamental sources of diversity among birds, and even Within species, dimensions may vary across populations within species, between the sexes and depending on age and condition. For measurements to be useful, they must be well-defined to be consistent and comparable with those taken by others or at other points in time. Measurements can be useful to identify species, quantify functional and ecomorphological differences, study growth, variation between geographically separated forms, identify differences between the sexes, age or otherwise characterize individual birds. While certain measurements are regularly taken to study living birds, others apply only to specimens in bird collections or are measurable only in the laboratory. The conventions used for measurement can vary between authors and works, making comparisons of sizes a matter that needs considerable care. (Full article...)
The bushshrikes are smallish passerine birds. They were formerly classed with the true shrikes in the family Laniidae, but are now considered sufficiently distinctive to be separated from that group as the family Malaconotidae, a name that alludes to their fluffy back and rump feathers.
Like their shrike-like relatives, the helmetshrikes, the bushshrikes have arisen in Africa in relatively recent times. The family is endemic to sub-Saharan Africa but completely absent from Madagascar, where the vangas are their closest relatives. They are found in scrub or open woodland, and less often in marshes, Afromontane or tropical forest. They are similar in habits to shrikes, hunting insects and other small prey from a perch on a bush. Although similar in build to the shrikes, these tend to be either colourful species or largely black; some species are quite secretive.
Some bushshrikes have flamboyant displays. The male puffbacks puff out the loose feathers on their rump and lower back, to look almost ball-like. (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
“ | If it looks like a duck, and quacks like a duck, we have at least to consider the possibility that we have a small aquatic bird of the family Anatidae on our hands. | ” |
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 pessulus is a delicate bar of cartilage connecting the dorsal and ventral extremities of the first pair of bronchial cartilages in the syrinx of birds. In some birds such as Anas platyrhynchos the pessulus may be ossified. (Full article...)
Create requested articles (WikiProject Birds – Article requests):
Do these tasks:
![]() |
Here are some tasks awaiting attention:
|
More outstanding tasks at the project's cleanup listing, Category:Birds articles needing attention, and Wikipedia:WikiProject Birds/Todo.
Class Aves, divided into superorders, orders, suborders (where indicated), and families. | ||||
---|---|---|---|---|
|
The following Wikimedia Foundation sister projects provide more on this subject: