Changes: Birds

Latest revision as of 15:41, 28 October 2013

Animals · Animal ethology · Comparative psychology · Animal models · Outline · Index

This article needs rewriting to enhance its relevance to psychologists..
Please help to improve this page yourself if you can..

?Birds
Fossil range: Late Jurassic–Recent, Template:Fossil range

Scarlet Robin, Petroica boodang

Scarlet Robin, Petroica boodang

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Class:	Aves Linnaeus, 1758^[1]

Subclasses & orders

About two dozen modern orders and several extinct orders and subclasses

Birds (class Aves) are winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. There are around 10,000 living species, making them the most varied of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from the Template:Convert/cmTemplate:Convert/test/Aon Bee Hummingbird to the Template:Convert/LoffAonDbSoffTemplate:Convert/test/Aon Ostrich. The fossil record indicates that birds evolved from theropod dinosaurs during the Jurassic period, around 150–200 Ma (million years ago), and the earliest known bird is the Late Jurassic Archaeopteryx, c 150–145 Ma. Most paleontologists regard birds as the only clade of dinosaurs to have survived the Cretaceous–Tertiary extinction event approximately 65.5 Ma.

Modern birds are characterised by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. All birds have wings, which are evolved forelimbs, and most can fly, with some exceptions including ratites, penguins, and a number of diverse endemic island species. Birds also have unique digestive and respiratory systems that are highly adapted for flight. Some birds, especially corvids and parrots, are among the most intelligent animal species; a number of bird species have been observed manufacturing and using tools, and many social species exhibit cultural transmission of knowledge across generations.

Many species undertake long distance annual migrations, and many more perform shorter irregular movements. Birds are social; they communicate using visual signals and through calls and songs, and participate in social behaviours including cooperative breeding and hunting, flocking, and mobbing of predators. The vast majority of bird species are socially monogamous, usually for one breeding season at a time, sometimes for years, but rarely for life. Other species have breeding systems that are polygynous ("many females") or, rarely, polyandrous ("many males"). Eggs are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching.

Classification

Main article: Bird families

The classification of birds is a contentious issue. Sibley and Ahlquist's Phylogeny and Classification of Birds (1990) is a landmark work on the classification of birds,^[2] although it is frequently debated and constantly revised. Most evidence seems to suggest that the assignment of orders is accurate,^[3] but scientists disagree about the relationships between the orders themselves; evidence from modern bird anatomy, fossils and DNA have all been brought to bear on the problem, but no strong consensus has emerged. More recently, new fossil and molecular evidence is providing an increasingly clear picture of the evolution of modern bird orders.

Modern bird orders: Classification

Neornithes

Palaeognathae

	Struthioniformes

	Tinamiformes

Neognathae

Other birds (Neoaves)

Galloanserae

	Anseriformes

	Galliformes

Basal divergences of modern birds
based on Sibley-Ahlquist taxonomy

Birds live and breed in most terrestrial habitats and on all seven continents, reaching their southern extreme in the Snow Petrel's breeding colonies up to Template:Convert/kmTemplate:Convert/test/A inland in Antarctica.^[4] The highest bird diversity occurs in tropical regions. It was earlier thought that this high diversity was the result of higher speciation rates in the tropics, however recent studies found higher speciation rates in the high latitudes that were offset by greater extinction rates than in the tropics.^[5] Several families of birds have adapted to life both on the world's oceans and in them, with some seabird species coming ashore only to breed^[6] and some penguins have been recorded diving up to 300 metres (Template:Convert/ft)Template:Convert/test/A.^[7]

Many bird species have established breeding populations in areas to which they have been introduced by humans. Some of these introductions have been deliberate; the Ring-necked Pheasant, for example, has been introduced around the world as a game bird.^[8] Others have been accidental, such as the establishment of wild Monk Parakeets in several North American cities after their escape from captivity.^[9] Some species, including Cattle Egret,^[10] Yellow-headed Caracara^[11] and Galah,^[12] have spread naturally far beyond their original ranges as agricultural practices created suitable new habitat.

Anatomy and physiology

Main article: Bird anatomy

File:Birdmorphology.svg

External anatomy of a bird: 1 Beak, 2 Head, 3 Iris, 4 Pupil, 5 Mantle, 6 Lesser coverts, 7 Scapulars, 8 Median coverts, 9 Tertials, 10 Rump, 11 Primaries, 12 Vent, 13 Thigh, 14 Tibio-tarsal articulation, 15 Tarsus, 16 Foot, 17 Tibia, 18 Belly, 19 Flanks, 20 Breast, 21 Throat, 22 Wattle

Compared with other vertebrates, birds have a body plan that shows many unusual adaptations, mostly to facilitate flight.

The skeleton consists of very lightweight bones. They have large air-filled cavities (called pneumatic cavities) which connect with the respiratory system.^[13] The skull bones are fused and do not show cranial sutures.^[14] The orbits are large and separated by a bony septum. The spine has cervical, thoracic, lumbar and caudal regions with the number of cervical (neck) vertebrae highly variable and especially flexible, but movement is reduced in the anterior thoracic vertebrae and absent in the later vertebrae.^[15] The last few are fused with the pelvis to form the synsacrum.^[14] The ribs are flattened and the sternum is keeled for the attachment of flight muscles except in the flightless bird orders. The forelimbs are modified into wings.^[16]

Like the reptiles, birds are primarily uricotelic, that is, their kidneys extract nitrogenous wastes from their bloodstream and excrete it as uric acid instead of urea or ammonia via the ureters into the intestine. Birds do not have a urinary bladder or external urethral opening and uric acid is excreted along with feces as a semisolid waste.^[17]^[18] However, birds such as hummingbirds can be facultatively ammonotelic, excreting most of the nitrogenous wastes as ammonia.^[19] They also excrete creatine, rather than creatinine like mammals.^[14] This material, as well as the output of the intestines, emerges from the bird's cloaca.^[20]^[21] The cloaca is a multi-purpose opening: waste is expelled through it, birds mate by joining cloaca, and females lay eggs from it. In addition, many species of birds regurgitate pellets.^[22] The digestive system of birds is unique, with a crop for storage and a gizzard that contains swallowed stones for grinding food to compensate for the lack of teeth.^[23] Most birds are highly adapted for rapid digestion to aid with flight.^[24] Some migratory birds have adapted to use protein from many parts of their bodies, including protein from the intestines, as additional energy during migration.^[25]

Birds have one of the most complex respiratory systems of all animal groups.^[14] Upon inhalation, 75% of the fresh air bypasses the lungs and flows directly into a posterior air sac which extends from the lungs and connects with air spaces in the bones and fills them with air. The other 25% of the air goes directly into the lungs. When the bird exhales, the used air flows out of the lung and the stored fresh air from the posterior air sac is simultaneously forced into the lungs. Thus, a bird's lungs receive a constant supply of fresh air during both inhalation and exhalation.^[26] Sound production is achieved using the syrinx, a muscular chamber incorporating multiple tympanic membranes which diverges from the lower end of the trachea.^[27] The bird's heart has four chambers and the right aortic arch gives rise to systemic circulation (unlike in the mammals where the left arch is involved).^[14] The postcava receives blood from the limbs via the renal portal system. Unlike in mammals, the red blood cells in birds have a nucleus.^[28]

The nervous system is large relative to the bird's size.^[14] The most developed part of the brain is the one that controls the flight-related functions, while the cerebellum coordinates movement and the cerebrum controls behaviour patterns, navigation, mating and nest building. Most birds have a poor sense of smell with notable exceptions including kiwis,^[29] New World vultures^[30] and tubenoses.^[31] The avian visual system is usually highly developed. Water birds have special flexible lenses, allowing accommodation for vision in air and water.^[14] Some species also have dual fovea. Birds are tetrachromatic, possessing ultraviolet (UV) sensitive cone cells in the eye as well as green, red and blue ones.^[32] This allows them to perceive ultraviolet light, which is involved in courtship. Many birds show plumage patterns in ultraviolet that are invisible to the human eye; some birds whose sexes appear similar to the naked eye are distinguished by the presence of ultraviolet reflective patches on their feathers. Male Blue Tits have an ultraviolet reflective crown patch which is displayed in courtship by posturing and raising of their nape feathers.^[33] Ultraviolet light is also used in foraging—kestrels have been shown to search for prey by detecting the UV reflective urine trail marks left on the ground by rodents.^[34] The eyelids of a bird are not used in blinking. Instead the eye is lubricated by the nictitating membrane, a third eyelid that moves horizontally.^[35] The nictitating membrane also covers the eye and acts as a contact lens in many aquatic birds.^[14] The bird retina has a fan shaped blood supply system called the pecten.^[14] Most birds cannot move their eyes, although there are exceptions, such as the Great Cormorant.^[36] Birds with eyes on the sides of their heads have a wide visual field, while birds with eyes on the front of their heads, such as owls, have binocular vision and can estimate the depth of field.^[37] The avian ear lacks external pinnae but is covered by feathers, although in some birds, such as the Asio, Bubo and Otus owls, these feathers form tufts which resemble ears. The inner ear has a cochlea, but it is not spiral as in mammals.^[38]

A few species are able to use chemical defenses against predators; some Procellariiformes can eject an unpleasant oil against an aggressor,^[39] and some species of pitohuis from New Guinea have a powerful neurotoxin in their skin and feathers.^[40]

Chromosomes

Birds have two sexes: male and female. The sex of birds is determined by the Z and W sex chromosomes, rather than by the X and Y chromosomes present in mammals. Male birds have two Z chromosomes (ZZ), and female birds have a W chromosome and a Z chromosome (WZ).^[14]

In nearly all species of birds, an individual's sex is determined at fertilization. However, one recent study demonstrated temperature-dependent sex determination among Australian Brush-turkeys, for which higher temperatures during incubation resulted in a higher female-to-male sex ratio.^[41]

Feathers, plumage, and scales

Main article: Feather

File:African Scops owl.jpg

The plumage of the African Scops Owl allows it to blend in with its surroundings.

Feathers are a feature characteristic of birds (though also present in some dinosaurs not currently considered to be true birds). They facilitate flight, provide insulation that aids in thermoregulation, and are used in display, camouflage, and signaling.^[14] There are several types of feathers, each serving its own set of purposes. Feathers are epidermal growths attached to the skin and arise only in specific tracts of skin called pterylae. The distribution pattern of these feather tracts (pterylosis) is used in taxonomy and systematics. The arrangement and appearance of feathers on the body, called plumage, may vary within species by age, social status,^[42] and sex.^[43]

Plumage is regularly moulted; the standard plumage of a bird that has moulted after breeding is known as the "non-breeding" plumage, or – in the Humphrey-Parkes terminology – "basic" plumage; breeding plumages or variations of the basic plumage are known under the Humphrey-Parkes system as "alternate" plumages.^[44] Moulting is annual in most species, although some may have two moults a year, and large birds of prey may moult only once every few years. Moulting patterns vary across species. In passerines, flight feathers are replaced one at a time with the innermost primary being the first. When the fifth of sixth primary is replaced, the outermost tertiaries begin to drop. After the innermost tertiaries are moulted, the secondaries starting from the innermost begin to drop and this proceeds to the outer feathers (centrifugal moult). The greater primary coverts are moulted in synchrony with the primary that they overlap.^[45] A small number of species, such as ducks and geese, lose all of their flight feathers at once, temporarily becoming flightless.^[46] As a general rule, the tail feathers are moulted and replaced starting with the innermost pair.^[45] Centripetal moults of tail feathers are however seen in the Phasianidae.^[47] The centrifugal moult is modified in the tail feathers of woodpeckers and treecreepers, in that it begins with the second innermost pair of feathers and finishes with the central pair of feathers so that the bird maintains a functional climbing tail.^[45]^[48] The general pattern seen in passerines is that the primaries are replaced outward, secondaries inward, and the tail from center outward.^[49] Before nesting, the females of most bird species gain a bare brood patch by losing feathers close to the belly. The skin there is well supplied with blood vessels and helps the bird in incubation.^[50]

File:Red Lory (Eos bornea)-6.jpg

Red Lory preening

Feathers require maintenance and birds preen or groom them daily, spending an average of around 9% of their daily time on this.^[51] The bill is used to brush away foreign particles and to apply waxy secretions from the uropygial gland; these secretions protect the feathers' flexibility and act as an antimicrobial agent, inhibiting the growth of feather-degrading bacteria.^[52] This may be supplemented with the secretions of formic acid from ants, which birds receive through a behaviour known as anting, to remove feather parasites.^[53]

The scales of birds are composed of the same keratin as beaks, claws, and spurs. They are found mainly on the toes and metatarsus, but may be found further up on the ankle in some birds. Most bird scales do not overlap significantly, except in the cases of kingfishers and woodpeckers. The scales of birds are thought to be homologous to those of reptiles and mammals.^[54]

Flight

Main article: Bird flight

File:Restless flycatcher04.jpg

Restless Flycatcher in the downstroke of flapping flight

Most birds can fly, which distinguishes them from almost all other vertebrate classes. Flight is the primary means of locomotion for most bird species and is used for breeding, feeding, and predator avoidance and escape. Birds have various adaptations for flight, including a lightweight skeleton, two large flight muscles, the pectoralis, which accounts for 15% of the total mass of the bird, and the supracoracoideus, as well as a modified forelimb (wing) that serves as an aerofoil.^[14] Wing shape and size generally determine a bird species' type of flight; many birds combine powered, flapping flight with less energy-intensive soaring flight. About 60 extant bird species are flightless, as were many extinct birds.^[55] Flightlessness often arises in birds on isolated islands, probably due to limited resources and the absence of land predators.^[56] Though flightless, penguins use similar musculature and movements to "fly" through the water, as do auks, shearwaters and dippers.^[57]

Behaviour

Most birds are diurnal, but some birds, such as many species of owls and nightjars, are nocturnal or crepuscular (active during twilight hours), and many coastal waders feed when the tides are appropriate, by day or night.^[58]

Diet and feeding

File:BirdBeaksA.svg

Feeding adaptations in beaks

Birds' diets are varied and often include nectar, fruit, plants, seeds, carrion, and various small animals, including other birds.^[14] Because birds have no teeth, their digestive system is adapted to process unmasticated food items that are swallowed whole.

Birds that employ many strategies to obtain food or feed on a variety of food items are called generalists, while others that concentrate time and effort on specific food items or have a single strategy to obtain food are considered specialists.^[14] Birds' feeding strategies vary by species. Many birds glean for insects, invertebrates, fruit, or seeds. Some hunt insects by suddenly attacking from a branch. Nectar feeders such as hummingbirds, sunbirds, lories, and lorikeets amongst others have specially adapted brushy tongues and in many cases bills designed to fit co-adapted flowers.^[59] Kiwis and shorebirds with long bills probe for invertebrates; shorebirds' varied bill lengths and feeding methods result in the separation of ecological niches.^[14]^[60] Loons, diving ducks, penguins and auks pursue their prey underwater, using their wings or feet for propulsion,^[6] while aerial predators such as sulids, kingfishers and terns plunge dive after their prey. Flamingos, three species of prion, and some ducks are filter feeders.^[61]^[62] Geese and dabbling ducks are primarily grazers.

Some species, including frigatebirds, gulls,^[63] and skuas,^[64] engage in kleptoparasitism, stealing food items from other birds. Kleptoparasitism is thought to be a supplement to food obtained by hunting, rather than a significant part of any species' diet; a study of Great Frigatebirds stealing from Masked Boobies estimated that the frigatebirds stole at most 40% of their food and on average stole only 5%.^[65] Other birds are scavengers; some of these, like vultures, are specialised carrion eaters, while others, like gulls, corvids, or other birds of prey, are opportunists.^[66]

Water and drinking

Water is needed by many birds although their mode of excretion and lack of sweat glands reduces the physiological demands.^[67] Some desert birds can obtain their water needs entirely from moisture in their food. They may also have other adaptations such as allowing their body temperature to rise, saving on moisture loss from evaporative cooling or panting.^[68] Seabirds can drink seawater and have salt glands inside the head that eliminate excess salt out of the nostrils.^[69]

Most birds scoop water in their beaks and raise their head to let water run down the throat. Some species, especially of arid zones, belonging to the pigeon, finch, mousebird, button-quail and bustard families are capable of sucking up water without the need to tilt back their heads.^[70] Some desert birds depend on water sources and sandgrouse are particularly well-known for their daily congregations at waterholes. Nesting sandgrouse carry water to their young by wetting their belly feathers.^[71]

Migration

Main article: Bird migration

Many bird species migrate to take advantage of global differences of seasonal temperatures, therefore optimising availability of food sources and breeding habitat. These migrations vary among the different groups. Many landbirds, shorebirds, and waterbirds undertake annual long distance migrations, usually triggered by the length of daylight as well as weather conditions. These birds are characterised by a breeding season spent in the temperate or arctic/antarctic regions and a non-breeding season in the tropical regions or opposite hemisphere. Before migration, birds substantially increase body fats and reserves and reduce the size of some of their organs.^[25]^[72] Migration is highly demanding energetically, particularly as birds need to cross deserts and oceans without refuelling. Landbirds have a flight range of around Template:Convert/kmTemplate:Convert/test/Aon and shorebirds can fly up to Template:Convert/kmTemplate:Convert/test/Aon,^[73] although the Bar-tailed Godwit is capable of non-stop flights of up to Template:Convert/kmTemplate:Convert/test/Aon.^[74] Seabirds also undertake long migrations, the longest annual migration being those of Sooty Shearwaters, which nest in New Zealand and Chile and spend the northern summer feeding in the North Pacific off Japan, Alaska and California, an annual round trip of Template:Convert/kmTemplate:Convert/test/Aon.^[75] Other seabirds disperse after breeding, travelling widely but having no set migration route. Albatrosses nesting in the Southern Ocean often undertake circumpolar trips between breeding seasons.^[76]

File:Bar-tailed Godwit migration.jpg

The routes of satellite-tagged Bar-tailed Godwits migrating north from New Zealand. This species has the longest known non-stop migration of any species, up to Template:Convert/kmTemplate:Convert/test/Aon.

Some bird species undertake shorter migrations, travelling only as far as is required to avoid bad weather or obtain food. Irruptive species such as the boreal finches are one such group and can commonly be found at a location in one year and absent the next. This type of migration is normally associated with food availability.^[77] Species may also travel shorter distances over part of their range, with individuals from higher latitudes travelling into the existing range of conspecifics; others undertake partial migrations, where only a fraction of the population, usually females and subdominant males, migrates.^[78] Partial migration can form a large percentage of the migration behaviour of birds in some regions; in Australia, surveys found that 44% of non-passerine birds and 32% of passerines were partially migratory.^[79] Altitudinal migration is a form of short distance migration in which birds spend the breeding season at higher altitudes elevations and move to lower ones during suboptimal conditions. It is most often triggered by temperature changes and usually occurs when the normal territories also become inhospitable due to lack of food.^[80] Some species may also be nomadic, holding no fixed territory and moving according to weather and food availability. Parrots as a family are overwhelmingly neither migratory nor sedentary but considered to either be dispersive, irruptive, nomadic or undertake small and irregular migrations.^[81]

The ability of birds to return to precise locations across vast distances has been known for some time; in an experiment conducted in the 1950s a Manx Shearwater released in Boston returned to its colony in Skomer, Wales, within 13 days, a distance of Template:Convert/kmTemplate:Convert/test/Aon.^[82] Birds navigate during migration using a variety of methods. For diurnal migrants, the sun is used to navigate by day, and a stellar compass is used at night. Birds that use the sun compensate for the changing position of the sun during the day by the use of an internal clock.^[14] Orientation with the stellar compass depends on the position of the constellations surrounding Polaris.^[83] These are backed up in some species by their ability to sense the Earth's geomagnetism through specialised photoreceptors.^[84]

Communication

File:Stavenn Eurypiga helias 00.jpg

The startling display of the Sunbittern mimics a large predator.

Birds communicate using primarily visual and auditory signals. Signals can be interspecific (between species) and intraspecific (within species).

Birds sometimes use plumage to assess and assert social dominance,^[85] to display breeding condition in sexually selected species, or to make threatening displays, as in the Sunbittern's mimicry of a large predator to ward off hawks and protect young chicks.^[86] Variation in plumage also allows for the identification of birds, particularly between species. Visual communication among birds may also involve ritualised displays, which have developed from non-signalling actions such as preening, the adjustments of feather position, pecking, or other behaviour. These displays may signal aggression or submission or may contribute to the formation of pair-bonds.^[14] The most elaborate displays occur during courtship, where "dances" are often formed from complex combinations of many possible component movements;^[87] males' breeding success may depend on the quality of such displays.^[88]

File:Troglodytes aedon.ogg

Call of the House Wren, a common North American songbird

Bird calls and songs, which are produced in the syrinx, are the major means by which birds communicate with sound. This communication can be very complex; some species can operate the two sides of the syrinx independently, allowing the simultaneous production of two different songs.^[27] Calls are used for a variety of purposes, including mate attraction,^[14] evaluation of potential mates,^[89] bond formation, the claiming and maintenance of territories,^[14] the identification of other individuals (such as when parents look for chicks in colonies or when mates reunite at the start of breeding season),^[90] and the warning of other birds of potential predators, sometimes with specific information about the nature of the threat.^[91] Some birds also use mechanical sounds for auditory communication. The Coenocorypha snipes of New Zealand drive air through their feathers,^[92] woodpeckers drum territorially,^[24] and Palm Cockatoos use tools to drum.^[93]

Flocking and other associations

File:Red-billed quelea flocking at waterhole.jpg

Red-billed Queleas, the most numerous species of bird,^[94] form enormous flocks—sometimes tens of thousands strong.

While some birds are essentially territorial or live in small family groups, other birds may form large flocks. The principal benefits of flocking are safety in numbers and increased foraging efficiency.^[14] Defence against predators is particularly important in closed habitats like forests, where ambush predation is common and multiple eyes can provide a valuable early warning system. This has led to the development of many mixed-species feeding flocks, which are usually composed of small numbers of many species; these flocks provide safety in numbers but reduce potential competition for resources.^[95] Costs of flocking include bullying of socially subordinate birds by more dominant birds and the reduction of feeding efficiency in certain cases.^[96]

Birds sometimes also form associations with non-avian species. Plunge-diving seabirds associate with dolphins and tuna, which push shoaling fish towards the surface.^[97] Hornbills have a mutualistic relationship with Dwarf Mongooses, in which they forage together and warn each other of nearby birds of prey and other predators.^[98]

Resting and roosting

File:Caribbean Flamingo2 (Phoenicopterus ruber) (0424) - Relic38.jpg

Many birds, like this American Flamingo, tuck their head into their back when sleeping

The high metabolic rates of birds during the active part of the day is supplemented by rest at other times. Sleeping birds often use a type of sleep known as vigilant sleep, where periods of rest are interspersed with quick eye-opening 'peeks', allowing them to be sensitive to disturbances and enable rapid escape from threats.^[99] Swifts are believed to be able to sleep in flight and radar observations suggest that they orient themselves to face the wind in their roosting flight.^[100] It has been suggested that there may be certain kinds of sleep which are possible even when in flight.^[101] Some birds have also demonstrated the capacity to fall into slow-wave sleep one hemisphere of the brain at a time. The birds tend to exercise this ability depending upon its position relative to the outside of the flock. This may allow the eye opposite the sleeping hemisphere to remain vigilant for predators by viewing the outer margins of the flock. This adaptation is also known from marine mammals.^[102] Communal roosting is common because it lowers the loss of body heat and decreases the risks associated with predators.^[103] Roosting sites are often chosen with regard to thermoregulation and safety.^[104]

Many sleeping birds bend their heads over their backs and tuck their bills in their back feathers, although others place their beaks among their breast feathers. Many birds rest on one leg, while some may pull up their legs into their feathers, especially in cold weather. Perching birds have a tendon locking mechanism that helps them hold on to the perch when they are asleep. Many ground birds, such as quails and pheasants, roost in trees. A few parrots of the genus Loriculus roost hanging upside down.^[105] Some hummingbirds go into a nightly state of torpor accompanied with a reduction of their metabolic rates.^[106] This physiological adaptation shows in nearly a hundred other species, including owlet-nightjars, nightjars, and woodswallows. One species, the Common Poorwill, even enters a state of hibernation.^[107] Birds do not have sweat glands, but they may cool themselves by moving to shade, standing in water, panting, increasing their surface area, fluttering their throat or by using special behaviours like urohidrosis to cool themselves.

Breeding

Social systems

File:Raggiana Bird-of-Paradise wild 5.jpg

Like others of its family the male Raggiana Bird of Paradise has elaborate breeding plumage used to impress females.^[108]

Ninety-five percent of bird species are socially monogamous. These species pair for at least the length of the breeding season or—in some cases—for several years or until the death of one mate.^[109] Monogamy allows for biparental care, which is especially important for species in which females require males' assistance for successful brood-rearing.^[110] Among many socially monogamous species, extra-pair copulation (infidelity) is common.^[111] Such behaviour typically occurs between dominant males and females paired with subordinate males, but may also be the result of forced copulation in ducks and other anatids.^[112] For females, possible benefits of extra-pair copulation include getting better genes for her offspring and insuring against the possibility of infertility in her mate.^[113] Males of species that engage in extra-pair copulations will closely guard their mates to ensure the parentage of the offspring that they raise.^[114]

Other mating systems, including polygyny, polyandry, polygamy, polygynandry, and promiscuity, also occur.^[14] Polygamous breeding systems arise when females are able to raise broods without the help of males.^[14] Some species may use more than one system depending on the circumstances.

Breeding usually involves some form of courtship display, typically performed by the male.^[115] Most displays are rather simple and involve some type of song. Some displays, however, are quite elaborate. Depending on the species, these may include wing or tail drumming, dancing, aerial flights, or communal lekking. Females are generally the ones that drive partner selection,^[116] although in the polyandrous phalaropes, this is reversed: plainer males choose brightly coloured females.^[117] Courtship feeding, billing and allopreening are commonly performed between partners, generally after the birds have paired and mated.^[24]

Territories, nesting and incubation

See also: Bird nest

Many birds actively defend a territory from others of the same species during the breeding season; maintenance of territories protects the food source for their chicks. Species that are unable to defend feeding territories, such as seabirds and swifts, often breed in colonies instead; this is thought to offer protection from predators. Colonial breeders defend small nesting sites, and competition between and within species for nesting sites can be intense.^[118]

File:Golden-backed Weaver.jpg

Male Golden-backed Weavers construct elaborate suspended nests out of grass.

All birds lay amniotic eggs with hard shells made mostly of calcium carbonate.^[14] Hole and burrow nesting species tend to lay white or pale eggs, while open nesters lay camouflaged eggs. There are many exceptions to this pattern, however; the ground-nesting nightjars have pale eggs, and camouflage is instead provided by their plumage. Species that are victims of brood parasites have varying egg colours to improve the chances of spotting a parasite's egg, which forces female parasites to match their eggs to those of their hosts.^[119]

Bird eggs are usually laid in a nest. Most species create somewhat elaborate nests, which can be cups, domes, plates, beds scrapes, mounds, or burrows.^[120] Some bird nests, however, are extremely primitive; albatross nests are no more than a scrape on the ground. Most birds build nests in sheltered, hidden areas to avoid predation, but large or colonial birds—which are more capable of defence—may build more open nests. During nest construction, some species seek out plant matter from plants with parasite-reducing toxins to improve chick survival,^[121] and feathers are often used for nest insulation.^[120] Some bird species have no nests; the cliff-nesting Common Guillemot lays its eggs on bare rock, and male Emperor Penguins keep eggs between their body and feet. The absence of nests is especially prevalent in ground-nesting species where the newly hatched young are precocial.

File:Eastern Phoebe-nest-Brown-headed-Cowbird-egg.jpg

Nest of an Eastern Phoebe that has been parasitised by a Brown-headed Cowbird

Incubation, which optimises temperature for chick development, usually begins after the last egg has been laid.^[14] In monogamous species incubation duties are often shared, whereas in polygamous species one parent is wholly responsible for incubation. Warmth from parents passes to the eggs through brood patches, areas of bare skin on the abdomen or breast of the incubating birds. Incubation can be an energetically demanding process; adult albatrosses, for instance, lose as much as 83 grams (Template:Convert/oz)Template:Convert/test/A of body weight per day of incubation.^[122] The warmth for the incubation of the eggs of megapodes comes from the sun, decaying vegetation or volcanic sources.^[123] Incubation periods range from 10 days (in woodpeckers, cuckoos and passerine birds) to over 80 days (in albatrosses and kiwis).^[14]

Parental care and fledging

At the time of their hatching, chicks range in development from helpless to independent, depending on their species. Helpless chicks are termed altricial, and tend to be born small, blind, immobile and naked; chicks that are mobile and feathered upon hatching are termed precocial. Altricial chicks need help thermoregulating and must be brooded for longer than precocial chicks. Chicks at neither of these extremes can be semi-precocial or semi-altricial.

File:Calliope-nest.jpg

A female Calliope Hummingbird feeding fully grown chicks

The length and nature of parental care varies widely amongst different orders and species. At one extreme, parental care in megapodes ends at hatching; the newly hatched chick digs itself out of the nest mound without parental assistance and can fend for itself immediately.^[124] At the other extreme, many seabirds have extended periods of parental care, the longest being that of the Great Frigatebird, whose chicks take up to six months to fledge and are fed by the parents for up to an additional 14 months.^[125]

In some species, both parents care for nestlings and fledglings; in others, such care is the responsibility of only one sex. In some species, other members of the same species—usually close relatives of the breeding pair, such as offspring from previous broods—will help with the raising of the young.^[126] Such alloparenting is particularly common among the Corvida, which includes such birds as the true crows, Australian Magpie and Fairy-wrens,^[127] but has been observed in species as different as the Rifleman and Red Kite. Among most groups of animals, male parental care is rare. In birds, however, it is quite common—more so than in any other vertebrate class.^[14] Though territory and nest site defence, incubation, and chick feeding are often shared tasks, there is sometimes a division of labour in which one mate undertakes all or most of a particular duty.^[128]

The point at which chicks fledge varies dramatically. The chicks of the Synthliboramphus murrelets, like the Ancient Murrelet, leave the nest the night after they hatch, following their parents out to sea, where they are raised away from terrestrial predators.^[129] Some other species, such as ducks, move their chicks away from the nest at an early age. In most species, chicks leave the nest just before, or soon after, they are able to fly. The amount of parental care after fledging varies; albatross chicks leave the nest on their own and receive no further help, while other species continue some supplementary feeding after fledging.^[130] Chicks may also follow their parents during their first migration.^[131]

Brood parasites

Main article: Brood parasite

File:Reed warbler cuckoo.jpg

Reed Warbler raising a Common Cuckoo, a brood parasite.

Brood parasitism, in which an egg-layer leaves her eggs with another individual's brood, is more common among birds than any other type of organism.^[132] After a parasitic bird lays her eggs in another bird's nest, they are often accepted and raised by the host at the expense of the host's own brood. Brood parasites may be either obligate brood parasites, which must lay their eggs in the nests of other species because they are incapable of raising their own young, or non-obligate brood parasites, which sometimes lay eggs in the nests of conspecifics to increase their reproductive output even though they could have raised their own young.^[133] One hundred bird species, including honeyguides, icterids, estrildid finches and ducks, are obligate parasites, though the most famous are the cuckoos.^[132] Some brood parasites are adapted to hatch before their host's young, which allows them to destroy the host's eggs by pushing them out of the nest or to kill the host's chicks; this ensures that all food brought to the nest will be fed to the parasitic chicks.^[134]

Ecology

File:Skua and penguin.jpeg

The South Polar Skua (left) is a generalist predator, taking the eggs of other birds, fish, carrion and other animals. This skua is attempting to push an Adelie Penguin (right) off its nest

Birds occupy a wide range of ecological positions.^[94] While some birds are generalists, others are highly specialised in their habitat or food requirements. Even within a single habitat, such as a forest, the niches occupied by different species of birds vary, with some species feeding in the forest canopy, others beneath the canopy, and still others on the forest floor. Forest birds may be insectivores, frugivores, and nectarivores. Aquatic birds generally feed by fishing, plant eating, and piracy or kleptoparasitism. Birds of prey specialise in hunting mammals or other birds, while vultures are specialised scavengers. Avivores are animals that are specialized at predating birds.

Some nectar-feeding birds are important pollinators, and many frugivores play a key role in seed dispersal.^[135] Plants and pollinating birds often coevolve,^[136] and in some cases a flower's primary pollinator is the only species capable of reaching its nectar.^[137]

Birds are often important to island ecology. Birds have frequently reached islands that mammals have not; on those islands, birds may fulfill ecological roles typically played by larger animals. For example, in New Zealand the moas were important browsers, as are the Kereru and Kokako today.^[135] Today the plants of New Zealand retain the defensive adaptations evolved to protect them from the extinct moa.^[138] Nesting seabirds may also affect the ecology of islands and surrounding seas, principally through the concentration of large quantities of guano, which may enrich the local soil^[139] and the surrounding seas.^[140]

A wide variety of Avian ecology field methods, including counts, nest monitoring, and capturing and marking, are used for researching avian ecology.

Relationship with humans

File:Industrial-Chicken-Coop.JPG

Industrial farming of chickens

Since birds are highly visible and common animals, humans have had a relationship with them since the dawn of man.^[141] Sometimes, these relationships are mutualistic, like the cooperative honey-gathering among honeyguides and African peoples such as the Borana.^[142] Other times, they may be commensal, as when species such as the House Sparrow^[143] have benefited from human activities. Several bird species have become commercially significant agricultural pests,^[144] and some pose an aviation hazard.^[145] Human activities can also be detrimental, and have threatened numerous bird species with extinction.

Religion, folklore and culture

File:Vogel Drei (Meister der Spielkarten).jpg

"The 3 of Birds" by the Master of the Playing Cards, 15th century Germany

Birds play prominent and diverse roles in folklore, religion, and popular culture. In religion, birds may serve as either messengers or priests and leaders for a deity, such as in the Cult of Makemake, in which the Tangata manu of Easter Island served as chiefs,^[146] or as attendants, as in the case of Hugin and Munin, two Common Ravens who whispered news into the ears of the Norse god Odin.^[147] Priests were involved in augury, or interpreting the words of birds while the "auspex" (from which the word "auspicious" is derived) watched their activities to foretell events.^[148] They may also serve as religious symbols, as when Jonah (Hebrew: יוֹנָה, dove) embodied the fright, passivity, mourning, and beauty traditionally associated with doves.^[149] Birds have themselves been deified, as in the case of the Common Peacock, which is perceived as Mother Earth by the Dravidians of India.^[150] Some birds have also been perceived as monsters, including the mythological Roc and the Māori's legendary Pouākai, a giant bird capable of snatching humans.^[151]

Birds have been featured in culture and art since prehistoric times, when they were represented in early cave paintings.^[152] Birds were later used in religious or symbolic art and design, such as the magnificent Peacock Throne of the Mughal and Persian emperors.^[153] With the advent of scientific interest in birds, many paintings of birds were commissioned for books. Among the most famous of these bird artists was John James Audubon, whose paintings of North American birds were a great commercial success in Europe and who later lent his name to the National Audubon Society.^[154] Birds are also important figures in poetry; for example, Homer incorporated Nightingales into his Odyssey, and Catullus used a sparrow as an erotic symbol in his Catullus 2.^[155] The relationship between an albatross and a sailor is the central theme of Samuel Taylor Coleridge's The Rime of the Ancient Mariner, which led to the use of the term as a metaphor for a 'burden'.^[156] Other English metaphors derive from birds; vulture funds and vulture investors, for instance, take their name from the scavenging vulture.^[157]

Perceptions of various bird species often vary across cultures. Owls are associated with bad luck, witchcraft, and death in parts of Africa,^[158] but are regarded as wise across much of Europe.^[159] Hoopoes were considered sacred in Ancient Egypt and symbols of virtue in Persia, but were thought of as thieves across much of Europe and harbingers of war in Scandinavia.^[160]

Notes

↑ Brands, Sheila Systema Naturae 2000 / Classification, Class Aves. Project: The Taxonomicon. URL accessed on 4 February 2009.
↑ Sibley, Charles; Jon Edward Ahlquist (1990). Phylogeny and classification of birds, New Haven: Yale University Press.
↑ Mayr, Ernst; Short, Lester L. (1970). Species Taxa of North American Birds: A Contribution to Comparative Systematics, Cambridge, Mass.: Nuttall Ornithological Club.
↑ Brooke, Michael (2004). Albatrosses And Petrels Across The World, Oxford: Oxford University Press.
↑ Weir, Jason T. (March 2007). The Latitudinal Gradient in Recent Speciation and Extinction Rates of Birds and Mammals. Science 315 (5818): 1574–76.
↑ ^6.0 ^6.1 Schreiber, Elizabeth Anne; Joanna Burger (2001). Biology of Marine Birds, Boca Raton: CRC Press.
↑ Sato, Katsufumi (1 May 2002). Buoyancy and maximal diving depth in penguins: do they control inhaling air volume?. Journal of Experimental Biology 205 (9): 1189–1197.
↑ Hill, David; Peter Robertson (1988). The Pheasant: Ecology, Management, and Conservation, Oxford: BSP Professional.
↑ Spreyer, Mark F., Enrique H. Bucher (1998). Monk Parakeet (Myiopsitta monachus). The Birds of North America. Cornell Lab of Ornithology.
↑ Arendt, Wayne J. (1 January 1988). Range Expansion of the Cattle Egret, (Bubulcus ibis) in the Greater Caribbean Basin. Colonial Waterbirds 11 (2): 252–62.
↑ Bierregaard, R.O. (1994). "Yellow-headed Caracara" Josep del Hoyo, Andrew Elliott and Jordi Sargatal (eds.) Handbook of the Birds of the World. Volume 2; New World Vultures to Guineafowl, Barcelona: Lynx Edicions.
↑ Juniper, Tony; Mike Parr (1998). Parrots: A Guide to the Parrots of the World, London: Christopher Helm.
↑ Ehrlich, Paul R., David S. Dobkin, and Darryl Wheye (1988). Adaptations for Flight. Birds of Stanford. Stanford University. URL accessed on 2007-12-13. Based on The Birder's Handbook (Paul Ehrlich, David Dobkin, and Darryl Wheye. 1988. Simon and Schuster, New York.)
↑ ^14.00 ^14.01 ^14.02 ^14.03 ^14.04 ^14.05 ^14.06 ^14.07 ^14.08 ^14.09 ^14.10 ^14.11 ^14.12 ^14.13 ^14.14 ^14.15 ^14.16 ^14.17 ^14.18 ^14.19 ^14.20 ^14.21 ^14.22 ^14.23 ^14.24 ^14.25 Gill, Frank (1995). Ornithology, New York: WH Freeman and Co.
↑ includeonly>"The Avian Skeleton", paulnoll.com. Retrieved on 2007-12-13.
↑ includeonly>"Skeleton of a typical bird", Fernbank Science Center's Ornithology Web. Retrieved on 2007-12-13.
↑ Ehrlich, Paul R., David S. Dobkin, and Darryl Wheye (1988). Drinking. Birds of Stanford. Standford University. URL accessed on 2007-12-13.
↑ Tsahar, Ella (March 2005). Can birds be ammonotelic? Nitrogen balance and excretion in two frugivores. Journal of Experimental Biology 208 (6): 1025–34.
↑ Preest, Marion R. (April 1997). Ammonia excretion by hummingbirds. Nature 386: 561–62.
↑ Mora, J. (July 1965). The Regulation of Urea-Biosynthesis Enzymes in Vertebrates. Biochemical Journal 96: 28–35.
↑ Packard, Gary C. (January 1966). The Influence of Ambient Temperature and Aridity on Modes of Reproduction and Excretion of Amniote Vertebrates. The American Naturalist 100 (916): 667–82.
↑ Balgooyen, Thomas G. (1 October 1971). Pellet Regurgitation by Captive Sparrow Hawks (Falco sparverius). Condor 73 (3): 382–85.
↑ Gionfriddo, James P. (1 February 1995). Grit Use by House Sparrows: Effects of Diet and Grit Size. Condor 97 (1): 57–67.
↑ ^24.0 ^24.1 ^24.2 Attenborough, David (1998). The Life of Birds, Princeton: Princeton University Press.
↑ ^25.0 ^25.1 Battley, Phil F. (January 2000). Empirical evidence for differential organ reductions during trans-oceanic bird flight. Proceedings of the Royal Society B 267 (1439): 191–5. (Erratum in Proceedings of the Royal Society B 267(1461):2567.)
↑ Maina, John N. (November 2006). Development, structure, and function of a novel respiratory organ, the lung-air sac system of birds: to go where no other vertebrate has gone. Biological Reviews 81 (4): 545–79.
↑ ^27.0 ^27.1 Suthers, Roderick A.; Sue Anne Zollinger (2004). "Producing song: the vocal apparatus" H. Philip Zeigler and Peter Marler (eds.) Behavioral Neurobiology of Birdsong, 109–129, New York: New York Academy of Sciences. PMID 15313772
↑ Scott, Robert B. (March 1966). Comparative hematology: The phylogeny of the erythrocyte. Annals of Hematology 12 (6): 340–51.
↑ Sales, James (2005). The endangered kiwi: a review. Folia Zoologica 54 (1–2): 1–20.
↑ Ehrlich, Paul R., David S. Dobkin, and Darryl Wheye (1988). The Avian Sense of Smell. Birds of Stanford. Standford University. URL accessed on 2007-12-13.
↑ Lequette, Benoit (1 August 1989). Olfaction in Subantarctic seabirds: Its phylogenetic and ecological significance. The Condor 91 (3): 732–35.
↑ Wilkie, Susan E. (February 1998). The molecular basis for UV vision in birds: spectral characteristics, cDNA sequence and retinal localization of the UV-sensitive visual pigment of the budgerigar (Melopsittacus undulatus). Biochemical Journal 330: 541–47.
↑ Andersson, S. (1998). Ultraviolet sexual dimorphism and assortative mating in blue tits. Proceeding of the Royal Society B 265 (1395): 445–50.
↑ Viitala, Jussi (1995). Attraction of kestrels to vole scent marks visible in ultraviolet light. Nature 373 (6513): 425–27.
↑ Williams, David L. (March 2003). Symblepharon with aberrant protrusion of the nictitating membrane in the snowy owl (Nyctea scandiaca). Veterinary Ophthalmology 6 (1): 11–13.
↑ White, Craig R. (July 2007). Vision and Foraging in Cormorants: More like Herons than Hawks?. PLoS ONE 2 (7): e639.
↑ Martin, Graham R. (1999). Visual fields in short-toed eagles, Circaetus gallicus (Accipitridae), and the function of binocularity in birds. Brain, Behaviour and Evolution 53 (2): 55–66.
↑ Saito, Nozomu (1978). Physiology and anatomy of avian ear. The Journal of the Acoustical Society of America 64 (S1): S3.
↑ Warham, John (1 May 1977). The Incidence, Function and ecological significance of petrel stomach oils. Proceedings of the New Zealand Ecological Society 24 (3): 84–93.
↑ Dumbacher, J.P. (October 1992). Homobatrachotoxin in the genus Pitohui: chemical defense in birds?. Science 258 (5083): 799–801.
↑ Göth, Anne (2007). Incubation temperatures and sex ratios in Australian brush-turkey (Alectura lathami) mounds. Austral Ecology 32 (4): 278–85.
↑ Belthoff, James R. (1 August 1994). Plumage Variation, Plasma Steroids and Social Dominance in Male House Finches. The Condor 96 (3): 614–25.
↑ Guthrie, R. Dale How We Use and Show Our Social Organs. Body Hot Spots: The Anatomy of Human Social Organs and Behavior. URL accessed on 2007-10-19.
↑ Humphrey, Philip S. (1 June 1959). An approach to the study of molts and plumages. The Auk 76 (2): 1–31.
↑ ^45.0 ^45.1 ^45.2 Pettingill Jr. OS (1970). Ornithology in Laboratory and Field, Burgess Publishing Co.
↑ de Beer SJ, Lockwood GM, Raijmakers JHFS, Raijmakers JMH, Scott WA, Oschadleus HD, Underhill LG (2001). SAFRING Bird Ringing Manual. SAFRING.
↑ Gargallo, Gabriel (1 June 1994). Flight Feather Moult in the Red-Necked Nightjar Caprimulgus ruficollis. Journal of Avian Biology 25 (2): 119–24.
↑ Mayr, Ernst (1954). The tail molt of small owls. The Auk 71 (2): 172–78.
↑ Payne, Robert B Birds of the World, Biology 532. Bird Division, University of Michigan Museum of Zoology. URL accessed on 2007-10-20.
↑ Turner, J. Scott (July 1997). On the thermal capacity of a bird's egg warmed by a brood patch. Physiological Zoology 70 (4): 470–80.
↑ Walther, Bruno A. (2005). Elaborate ornaments are costly to maintain: evidence for high maintenance handicaps. Behavioural Ecology 16 (1): 89–95.
↑ Shawkey, Matthew D. (2003). Chemical warfare? Effects of uropygial oil on feather-degrading bacteria. Journal of Avian Biology 34 (4): 345–49.
↑ Ehrlich, Paul R. (1986). The Adaptive Significance of Anting. The Auk 103 (4).
↑ Lucas, Alfred M. (1972). Avian Anatomy – integument, 67, 344, 394–601, East Lansing, Michigan, US: USDA Avian Anatomy Project, Michigan State University.
↑ Roots, Clive (2006). Flightless Birds, Westport: Greenwood Press.
↑ McNab, Brian K. (October 1994). Energy Conservation and the Evolution of Flightlessness in Birds. The American Naturalist 144 (4): 628–42.
↑ Kovacs, Christopher E. (May 2000). Anatomy and histochemistry of flight muscles in a wing-propelled diving bird, the Atlantic Puffin, Fratercula arctica. Journal of Morphology 244 (2): 109–25.
↑ Robert, Michel (January 1989). Conditions and significance of night feeding in shorebirds and other water birds in a tropical lagoon. The Auk 106 (1): 94–101.
↑ Paton, D. C. (1 April 1989). Bills and tongues of nectar-feeding birds: A review of morphology, function, and performance, with intercontinental comparisons. Australian Journal of Ecology 14 (4): 473–506.
↑ Baker, Myron Charles (1 April 1973). Niche Relationships Among Six Species of Shorebirds on Their Wintering and Breeding Ranges. Ecological Monographs 43 (2): 193–212.
↑ Cherel, Yves (2002). Food and feeding ecology of the sympatric thin-billed Pachyptila belcheri and Antarctic P. desolata prions at Iles Kerguelen, Southern Indian Ocean. Marine Ecology Progress Series 228: 263–81.
↑ Jenkin, Penelope M. (1957). The Filter-Feeding and Food of Flamingoes (Phoenicopteri). Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 240 (674): 401–93.
↑ Miyazaki, Masamine (1 July 1996). Vegetation cover, kleptoparasitism by diurnal gulls and timing of arrival of nocturnal Rhinoceros Auklets. The Auk 113 (3): 698–702.
↑ Bélisle, Marc (1 August 1995). Predation and kleptoparasitism by migrating Parasitic Jaegers. The Condor 97 (3): 771–781.
↑ Vickery, J. A. (1 May 1994). The Kleptoparasitic Interactions between Great Frigatebirds and Masked Boobies on Henderson Island, South Pacific. The Condor 96 (2): 331–40.
↑ Hiraldo, F.C. (1991). Unspecialized exploitation of small carcasses by birds. Bird Studies 38 (3): 200–07.
↑ Engel, Sophia Barbara (2005). Racing the wind: Water economy and energy expenditure in avian endurance flight, University of Groningen.
↑ Tieleman, B.I. (January 1999). The role of hyperthermia in the water economy of desert birds. Physiol. Biochem. Zool. 72 (1): 87–100.
↑ Schmidt-Nielsen, Knut (1 May 1960). The Salt-Secreting Gland of Marine Birds. Circulation 21 (5): 955–967.
↑ Hallager, Sara L. (1994). Drinking methods in two species of bustards. Wilson Bull. 106 (4): 763–764.
↑ MacLean, Gordon L. (1 June 1983). Water Transport by Sandgrouse. BioScience 33 (6): 365–369.
↑ Klaassen, Marc (1 January 1996). Metabolic constraints on long-distance migration in birds. Journal of Experimental Biology 199 (1): 57–64.
↑ Gill, Frank (1995). Ornithology, 2nd, New York: W.H. Freeman.
↑ includeonly>"Long-distance Godwit sets new record", BirdLife International, 2007-05-04. Retrieved on 2007-12-13.
↑ Shaffer, Scott A. (August 2006). Migratory shearwaters integrate oceanic resources across the Pacific Ocean in an endless summer. Proceedings of the National Academy of Sciences 103 (34): 12799–802.
↑ Croxall, John P. (January 2005). Global Circumnavigations: Tracking year-round ranges of nonbreeding Albatrosses. Science 307 (5707): 249–50.
↑ Wilson, W. Herbert, Jr. (1999). Bird feeding and irruptions of northern finches:are migrations short stopped?. North America Bird Bander 24 (4): 113–21.
↑ Nilsson, Anna L. K. (2006). Do partial and regular migrants differ in their responses to weather?. The Auk 123 (2): 537–47.
↑ Chan, Ken (2001). Partial migration in Australian landbirds: a review. Emu 101 (4): 281–92.
↑ Rabenold, Kerry N. (1985). Variation in Altitudinal Migration, Winter Segregation, and Site Tenacity in two subspecies of Dark-eyed Juncos in the southern Appalachians. The Auk 102 (4): 805–19.
↑ Collar, Nigel J. (1997). "Family Psittacidae (Parrots)" Josep del Hoyo, Andrew Elliott and Jordi Sargatal (eds.) Handbook of the Birds of the World, Volume 4: Sandgrouse to Cuckoos, Barcelona: Lynx Edicions.
↑ Matthews, G. V. T. (1 September 1953). Navigation in the Manx Shearwater. Journal of Experimental Biology 30 (2): 370–96.
↑ Mouritsen, Henrik (15 November 2001). Migrating songbirds tested in computer-controlled Emlen funnels use stellar cues for a time-independent compass. Journal of Experimental Biology 204 (8): 3855–65.
↑ Deutschlander, Mark E. (15 April 1999). The case for light-dependent magnetic orientation in animals. Journal of Experimental Biology 202 (8): 891–908.
↑ Möller, Anders Pape (1988). Badge size in the house sparrow Passer domesticus. Behavioral Ecology and Sociobiology 22 (5): 373–78.
↑ Thomas, Betsy Trent (1 August 1990). Nesting Behavior of Sunbitterns (Eurypyga helias) in Venezuela. The Condor 92 (3): 576–81.
↑ Pickering, S. P. C. (2001). Courtship behaviour of the Wandering Albatross Diomedea exulans at Bird Island, South Georgia. Marine Ornithology 29 (1): 29–37.
↑ Pruett-Jones, S. G. (1 May 1990). Sexual Selection Through Female Choice in Lawes' Parotia, A Lek-Mating Bird of Paradise. Evolution 44 (3): 486–501.
↑ Genevois, F. (1994). Male Blue Petrels reveal their body mass when calling. Ethology Ecology and Evolution 6 (3): 377–83.
↑ Jouventin, Pierre (June 1999). Finding a parent in a king penguin colony: the acoustic system of individual recognition. Animal Behaviour 57 (6): 1175–83.
↑ Templeton, Christopher N. (June 2005). Allometry of Alarm Calls: Black-Capped Chickadees Encode Information About Predator Size. Science 308 (5730): 1934–37.
↑ Miskelly, C. M. (July 1987). The identity of the hakawai. Notornis 34 (2): 95–116.
↑ Murphy, Stephen (2003). The breeding biology of palm cockatoos (Probosciger aterrimus): a case of a slow life history. Journal of Zoology 261 (4): 327–39.
↑ ^94.0 ^94.1 Sekercioglu, Cagan Hakki (2006). "Foreword" Josep del Hoyo, Andrew Elliott and David Christie (eds.) Handbook of the Birds of the World, Volume 11: Old World Flycatchers to Old World Warblers, Barcelona: Lynx Edicions.
↑ Terborgh, John (2005). Mixed flocks and polyspecific associations: Costs and benefits of mixed groups to birds and monkeys. American Journal of Primatology 21 (2): 87–100.
↑ Hutto, Richard L. (1 January 988). Foraging Behavior Patterns Suggest a Possible Cost Associated with Participation in Mixed-Species Bird Flocks. Oikos 51 (1): 79–83.
↑ Au, David W. K. (1 August 1986). Seabird interactions with Dolphins and Tuna in the Eastern Tropical Pacific. The Condor 88 (3): 304–17.
↑ Anne, O. (June 1983). Dwarf mongoose and hornbill mutualism in the Taru desert, Kenya. Behavioral Ecology and Sociobiology 12 (3): 181–90.
↑ Gauthier-Clerc, Michael (May 2000). Sleep-Vigilance Trade-off in Gadwall during the Winter Period. The Condor 102 (2): 307–13.
↑ Bäckman, Johan (1 April 2002). Harmonic oscillatory orientation relative to the wind in nocturnal roosting flights of the swift Apus apus. The Journal of Experimental Biology 205 (7): 905–910.
↑ Rattenborg, Niels C. (September 2006). Do birds sleep in flight?. Die Naturwissenschaften 93 (9): 413–25.
↑ Milius, S. (6 February 1999). Half-asleep birds choose which half dozes. Science News Online 155 (6).
↑ Beauchamp, Guy (1999). The evolution of communal roosting in birds: origin and secondary losses. Behavioural Ecology 10 (6): 675–87.
↑ Buttemer, William A. (1985). Energy relations of winter roost-site utilization by American goldfinches (Carduelis tristis). Oecologia 68 (1): 126–32.
↑ Buckley, F. G. (1 January 1968). Upside-down Resting by Young Green-Rumped Parrotlets (Forpus passerinus). The Condor 70 (1).
↑ Carpenter, F. Lynn (February 1974). Torpor in an Andean Hummingbird: Its Ecological Significance. Science 183 (4124): 545–47.
↑ McKechnie, Andrew E. (2007). Torpor in an African caprimulgid, the freckled nightjar Caprimulgus tristigma. Journal of Avian Biology 38 (3): 261–66.
↑ Frith, C.B. Displays of Count Raggi's Bird-of-Paradise Paradisaea raggiana and congeneric species. Emu 81 (4): 193–201.
↑ Freed, Leonard A. (1987). The Long-Term Pair Bond of Tropical House Wrens: Advantage or Constraint?. The American Naturalist 130 (4): 507–25.
↑ Gowaty, Patricia A. (1983). Male Parental Care and Apparent Monogamy among Eastern Bluebirds (Sialia sialis). The American Naturalist 121 (2): 149–60.
↑ Westneat, David F. (2003). Extra-pair paternity in birds: Causes, correlates, and conflict. Annual Review of Ecology, Evolution, and Systematics 34: 365–96.
↑ Gowaty, Patricia A. (1998). Ultimate causation of aggressive and forced copulation in birds: Female resistance, the CODE hypothesis, and social monogamy. American Zoologist 38 (1): 207–25.
↑ Sheldon, B (1994). Male Phenotype, Fertility, and the Pursuit of Extra-Pair Copulations by Female Birds. Proceedings: Biological Sciences 257 (1348): 25–30.
↑ Wei, G (2005). Copulations and mate guarding of the Chinese Egret. Waterbirds 28 (4): 527–30.
↑ Short, Lester L. (1993). Birds of the World and their Behavior, New York: Henry Holt and Co.
↑ Burton, R (1985). Bird Behavior, Alfred A. Knopf, Inc.
↑ Schamel, D (2004). Mate guarding, copulation strategies and paternity in the sex-role reversed, socially polyandrous red-necked phalarope Phalaropus lobatus. Behaviour Ecology and Sociobiology 57 (2): 110–18.
↑
Kokko H, Harris M, Wanless S (2004). "Competition for breeding sites and site-dependent population regulation in a highly colonial seabird, the common guillemot Uria aalge". Journal of Animal Ecology 73 (2): 367–76.
1. REDIRECT Template:Doi
↑
Booker L, Booker M (1991). "Why Are Cuckoos Host Specific?" Oikos 57 (3): 301–09.
1. REDIRECT Template:Doi
↑ ^120.0 ^120.1 Hansell M (2000). Bird Nests and Construction Behaviour. University of Cambridge Press ISBN 0-521-46038-7
↑
Lafuma L, Lambrechts M, Raymond M (2001). "Aromatic plants in bird nests as a protection against blood-sucking flying insects?" Behavioural Processes 56 (2) 113–20.
1. REDIRECT Template:Doi
↑ Warham, J. (1990) The Petrels – Their Ecology and Breeding Systems London: Academic Press ISBN 0127354204.
↑ Jones DN, Dekker, René WRJ, Roselaar, Cees S (1995). The Megapodes. Bird Families of the World 3. Oxford University Press: Oxford. ISBN 0-19-854651-3
↑ Elliot A (1994). "Family Megapodiidae (Megapodes)" in Handbook of the Birds of the World. Volume 2; New World Vultures to Guineafowl (eds del Hoyo J, Elliott A, Sargatal J) Lynx Edicions:Barcelona. ISBN 84-873337-15-6
↑ Metz VG, Schreiber EA (2002). "Great Frigatebird (Fregata minor)" In The Birds of North America, No 681, (Poole, A. and Gill, F., eds) The Birds of North America Inc: Philadelphia
↑
Ekman J (2006). "Family living amongst birds". Journal of Avian Biology 37 (4): 289–98.
1. REDIRECT Template:Doi
↑ Cockburn A (1996). "Why do so many Australian birds cooperate? Social evolution in the Corvida" Floyd R, Sheppard A, de Barro P Frontiers in Population Ecology, 21–42, Melbourne: CSIRO.
↑ Cockburn, Andrew (June 2006). Prevalence of different modes of parental care in birds. Proceedings: Biological Sciences 273 (1592): 1375–83.
↑ Gaston AJ (1994). Ancient Murrelet (Synthliboramphus antiquus). In The Birds of North America, No. 132 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.
↑
Schaefer HC, Eshiamwata GW, Munyekenye FB, Bohning-Gaese K (2004). "Life-history of two African Sylvia warblers: low annual fecundity and long post-fledging care". Ibis 146 (3): 427–37.
1. REDIRECT Template:Doi
↑
Alonso JC, Bautista LM, Alonso JA (2004). "Family-based territoriality vs flocking in wintering common cranes Grus grus". Journal of Avian Biology 35 (5): 434–44.
1. REDIRECT Template:Doi
↑ ^132.0 ^132.1 Davies N (2000). Cuckoos, Cowbirds and other Cheats. T. & A. D. Poyser: London ISBN 0-85661-135-2
↑ Sorenson M (1997). "Effects of intra- and interspecific brood parasitism on a precocial host, the canvasback, Aythya valisineria". Behavioral Ecology 8 (2) 153–61. PDF
↑
Spottiswoode C, Colebrook-Robjent J (2007). "Egg puncturing by the brood parasitic Greater Honeyguide and potential host counteradaptations". Behavioral Ecology
1. REDIRECT Template:Doi
↑ ^135.0 ^135.1 Clout M, Hay J (1989). "The importance of birds as browsers, pollinators and seed dispersers in New Zealand forests". New Zealand Journal of Ecology 12 27–33 PDF
↑
Stiles F (1981). "Geographical Aspects of Bird–Flower Coevolution, with Particular Reference to Central America". Annals of the Missouri Botanical Garden 68 (2) 323–51.
1. REDIRECT Template:Doi
↑ Temeles E, Linhart Y, Masonjones M, Masonjones H (2002). "The Role of Flower Width in Hummingbird Bill Length–Flower Length Relationships". Biotropica 34 (1): 68–80. PDF
↑
Bond W, Lee W, Craine J (2004). "Plant structural defences against browsing birds: a legacy of New Zealand's extinct moas". Oikos 104 (3), 500–08.
1. REDIRECT Template:Doi
↑ Wainright S, Haney J, Kerr C, Golovkin A, Flint M (1998). "Utilization of nitrogen derived from seabird guano by terrestrial and marine plants at St. Paul, Pribilof Islands, Bering Sea, Alaska". Marine Ecology 131 (1) 63–71. PDF
↑ Bosman A, Hockey A (1986). "Seabird guano as a determinant of rocky intertidal community structure". Marine Ecology Progress Series 32: 247–57 PDF
↑ Bonney, Rick (2004). Handbook of Bird Biology, Second, Princeton University Press.
↑ Dean W, Siegfried R, MacDonald I (1990). "The Fallacy, Fact, and Fate of Guiding Behavior in the Greater Honeyguide". Conservation Biology 4 (1) 99–101. PDF
↑
Singer R, Yom-Tov Y (1988). "The Breeding Biology of the House Sparrow Passer domesticus in Israel". Ornis Scandinavica 19 139–44.
1. REDIRECT Template:Doi
↑ Dolbeer R (1990). "Ornithology and integrated pest management: Red-winged blackbirds Agleaius phoeniceus and corn". Ibis 132 (2): 309–22.
↑ Dolbeer R, Belant J, Sillings J (1993). "Shooting Gulls Reduces Strikes with Aircraft at John F. Kennedy International Airport". Wildlife Society Bulletin 21: 442–50.
↑ Routledge S, Routledge K (1917). "The Bird Cult of Easter Island". Folklore 28 (4): 337–55.
↑
Chappell J (2006). "Living with the Trickster: Crows, Ravens, and Human Culture". PLoS Biol 4 (1):e14.
1. REDIRECT Template:Doi
↑ Ingersoll, Ernest (1923). "Birds in legend, fable and folklore". Longmans, Green and co. p. 214
↑
Hauser A (1985). "Jonah: In Pursuit of the Dove". Journal of Biblical Literature 104 (1): 21–37.
1. REDIRECT Template:Doi
↑
Nair P (1974). "The Peacock Cult in Asia". Asian Folklore Studies 33 (2): 93–170.
1. REDIRECT Template:Doi
↑ Tennyson A, Martinson P (2006). Extinct Birds of New Zealand Te Papa Press, Wellington ISBN 978-0-909010-21-8
↑
Meighan C (1966). "Prehistoric Rock Paintings in Baja California". American Antiquity 31 (3): 372–92.
1. REDIRECT Template:Doi
↑
Clarke CP (1908). "A Pedestal of the Platform of the Peacock Throne". The Metropolitan Museum of Art Bulletin 3 (10): 182–83.
1. REDIRECT Template:Doi
↑
Boime A (1999). "John James Audubon, a birdwatcher's fanciful flights". Art History 22 (5) 728–55.
1. REDIRECT Template:Doi
↑ Chandler A (1934). "The Nightingale in Greek and Latin Poetry". The Classical Journal 30 (2): 78–84.
↑
Lasky E (1992). "A Modern Day Albatross: The Valdez and Some of Life's Other Spills". The English Journal, 81 (3): 44–46.
1. REDIRECT Template:Doi
↑ Carson A (1998). "Vulture Investors, Predators of the 90s: An Ethical Examination". Journal of Business Ethics 17 (5): 543–55. PDF
↑ Enriquez PL, Mikkola H (1997). "Comparative study of general public owl knowledge in Costa Rica, Central America and Malawi, Africa". pp. 160–66 In: J.R. Duncan, D.H. Johnson, T.H. Nicholls, (Eds). Biology and conservation of owls of the Northern Hemisphere. General Technical Report NC-190, USDA Forest Service, St. Paul, Minnesota. 635 pp.
↑ Lewis DP (2005). Owls in Mythology and Culture. The Owl Pages. Retrieved on 15 September 2007
↑ Dupree N (1974). "An Interpretation of the Role of the Hoopoe in Afghan Folklore and Magic". Folklore 85 (3): 173–93.

External links

Avibase – The World Bird Database
Birdlife International – Dedicated to bird conservation worldwide; has a database with about 250,000 records on endangered bird species.
Bird biogeography
Birds and Science from the National Audubon Society
Cornell Lab of Ornithology
Essays on bird biology
International Ornithological Committee
North American Birds for Kids
Ornithology
Sora Searchable online research archive; Archives of the following ornithological journals The Auk, Condor, Journal of Field Ornithology, North American Bird Bander, Studies in Avian Biology, Pacific Coast Avifauna, and the Wilson Bulletin.
The Internet Bird Collection – A free library of videos of the world's birds
The Institute for Bird Populations, California
list of field guides to birds, from the International Field Guides database

Template:Chordata

-->

ace:Cicém af:Voël ar:طائر an:Aves arc:ܛܝܪܐ roa-rup:Aves frp:Usél ast:Páxaru gn:Guyra ay:Jamach'i az:Quşlar bn:পাখি zh-min-nan:Chiáu be:Птушкі be-x-old:Птахі bar:Fegl bo:བྱ། bs:Ptice br:Evn bg:Птици ca:Ocell cv:Кайăксем ceb:Langgam cs:Ptáci cy:Aderyn da:Fugl pdc:Voggel de:Vögel nv:Tsídii dsb:Ptaški et:Linnud el:Πτηνά es:Aves eo:Birdoj eu:Hegazti fa:پرنده fo:Fuglur fr:Oiseau fy:Fûgels ga:Éan gv:Ushag gd:Eun gl:Aves gu:પક્ષી xal:Шовуд ko:새 ha:Tsuntsu hi:पक्षी hsb:Ptaki hr:Ptice io:Ucelo id:Burung ia:Ave zu:Inyoni is:Fugl he:עופות jv:Manuk kn:ಪಕ್ಷಿ ka:ფრინველები kw:Edhen sw:Ndege (mnyama) ht:Zwazo ku:Çûk la:Aves lv:Putni lb:Vullen lt:Paukščiai li:Veugel ln:Ndɛkɛ jbo:cipni hu:Madarak mk:Птици mg:Vorona ml:പക്ഷി mr:पक्षी arz:طير ms:Burung mn:Шувуу nah:Tōtōtl nl:Vogels nds-nl:Voegel cr:Pileshish nap:Auciello no:Fugler nn:Fuglar nrm:Ouaîsé oc:Ausèl pnb:پنچھی nds:Vagels pt:Aves ro:Pasăre rm:Utschè qu:Pisqu ru:Птицы sah:Көтөрдөр sc:Aves stq:Fuugele scn:Aceddu simple:Bird ss:Tinyoni sk:Vtáky sl:Ptiči szl:Ptoki sr:Птице sh:Ptica su:Manuk fi:Linnut sv:Fåglar tl:Ibon ta:பறவை tt:Кошлар te:పక్షి th:นก tg:Парранда chr:ᏥᏍᏆ chy:Ve'kese uk:Птахи ur:پرندہ vec:Osei vi:Chim fiu-vro:Tsirk wa:Oujhea war:Tamsi yi:פויגל yo:Ẹyẹ zh-yue:雀 zea:Veugels bat-smg:Paukštē zh:鸟 -->

This page uses Creative Commons Licensed content from Wikipedia (view authors).

[1] Brands, Sheila Systema Naturae 2000 / Classification, Class Aves. Project: The Taxonomicon. URL accessed on 4 February 2009.

[2] Sibley, Charles; Jon Edward Ahlquist (1990). Phylogeny and classification of birds, New Haven: Yale University Press.

[3] Mayr, Ernst; Short, Lester L. (1970). Species Taxa of North American Birds: A Contribution to Comparative Systematics, Cambridge, Mass.: Nuttall Ornithological Club.

[4] Brooke, Michael (2004). Albatrosses And Petrels Across The World, Oxford: Oxford University Press.

[5] Weir, Jason T. (March 2007). The Latitudinal Gradient in Recent Speciation and Extinction Rates of Birds and Mammals. Science 315 (5818): 1574–76.

[Burger-6] 6.0 ^6.1 Schreiber, Elizabeth Anne; Joanna Burger (2001). Biology of Marine Birds, Boca Raton: CRC Press.

[7] Sato, Katsufumi (1 May 2002). Buoyancy and maximal diving depth in penguins: do they control inhaling air volume?. Journal of Experimental Biology 205 (9): 1189–1197.

[8] Hill, David; Peter Robertson (1988). The Pheasant: Ecology, Management, and Conservation, Oxford: BSP Professional.

[9] Spreyer, Mark F., Enrique H. Bucher (1998). Monk Parakeet (Myiopsitta monachus). The Birds of North America. Cornell Lab of Ornithology.

[10] Arendt, Wayne J. (1 January 1988). Range Expansion of the Cattle Egret, (Bubulcus ibis) in the Greater Caribbean Basin. Colonial Waterbirds 11 (2): 252–62.

[11] Bierregaard, R.O. (1994). "Yellow-headed Caracara" Josep del Hoyo, Andrew Elliott and Jordi Sargatal (eds.) Handbook of the Birds of the World. Volume 2; New World Vultures to Guineafowl, Barcelona: Lynx Edicions.

[12] Juniper, Tony; Mike Parr (1998). Parrots: A Guide to the Parrots of the World, London: Christopher Helm.

[13] Ehrlich, Paul R., David S. Dobkin, and Darryl Wheye (1988). Adaptations for Flight. Birds of Stanford. Stanford University. URL accessed on 2007-12-13. Based on The Birder's Handbook (Paul Ehrlich, David Dobkin, and Darryl Wheye. 1988. Simon and Schuster, New York.)

[Gill-14] 14.00 ^14.01 ^14.02 ^14.03 ^14.04 ^14.05 ^14.06 ^14.07 ^14.08 ^14.09 ^14.10 ^14.11 ^14.12 ^14.13 ^14.14 ^14.15 ^14.16 ^14.17 ^14.18 ^14.19 ^14.20 ^14.21 ^14.22 ^14.23 ^14.24 ^14.25 Gill, Frank (1995). Ornithology, New York: WH Freeman and Co.

[15] udeonly>"The Avian Skeleton", paulnoll.com. Retrieved on 2007-12-13.

[16] udeonly>"Skeleton of a typical bird", Fernbank Science Center's Ornithology Web. Retrieved on 2007-12-13.

[17] Ehrlich, Paul R., David S. Dobkin, and Darryl Wheye (1988). Drinking. Birds of Stanford. Standford University. URL accessed on 2007-12-13.

[18] Tsahar, Ella (March 2005). Can birds be ammonotelic? Nitrogen balance and excretion in two frugivores. Journal of Experimental Biology 208 (6): 1025–34.

[19] Preest, Marion R. (April 1997). Ammonia excretion by hummingbirds. Nature 386: 561–62.

[20] Mora, J. (July 1965). The Regulation of Urea-Biosynthesis Enzymes in Vertebrates. Biochemical Journal 96: 28–35.

[21] Packard, Gary C. (January 1966). The Influence of Ambient Temperature and Aridity on Modes of Reproduction and Excretion of Amniote Vertebrates. The American Naturalist 100 (916): 667–82.

[22] Balgooyen, Thomas G. (1 October 1971). Pellet Regurgitation by Captive Sparrow Hawks (Falco sparverius). Condor 73 (3): 382–85.

[23] Gionfriddo, James P. (1 February 1995). Grit Use by House Sparrows: Effects of Diet and Grit Size. Condor 97 (1): 57–67.

[Attenborough-24] 24.0 ^24.1 ^24.2 Attenborough, David (1998). The Life of Birds, Princeton: Princeton University Press.

[Battley-25] 25.0 ^25.1 Battley, Phil F. (January 2000). Empirical evidence for differential organ reductions during trans-oceanic bird flight. Proceedings of the Royal Society B 267 (1439): 191–5. (Erratum in Proceedings of the Royal Society B 267(1461):2567.)

[26] Maina, John N. (November 2006). Development, structure, and function of a novel respiratory organ, the lung-air sac system of birds: to go where no other vertebrate has gone. Biological Reviews 81 (4): 545–79.

[Suthers-27] 27.0 ^27.1 Suthers, Roderick A.; Sue Anne Zollinger (2004). "Producing song: the vocal apparatus" H. Philip Zeigler and Peter Marler (eds.) Behavioral Neurobiology of Birdsong, 109–129, New York: New York Academy of Sciences. PMID 15313772

[28] Scott, Robert B. (March 1966). Comparative hematology: The phylogeny of the erythrocyte. Annals of Hematology 12 (6): 340–51.

[29] Sales, James (2005). The endangered kiwi: a review. Folia Zoologica 54 (1–2): 1–20.

[Avian_Sense_of_Smell-30] Ehrlich, Paul R., David S. Dobkin, and Darryl Wheye (1988). The Avian Sense of Smell. Birds of Stanford. Standford University. URL accessed on 2007-12-13.

[31] Lequette, Benoit (1 August 1989). Olfaction in Subantarctic seabirds: Its phylogenetic and ecological significance. The Condor 91 (3): 732–35.

[32] Wilkie, Susan E. (February 1998). The molecular basis for UV vision in birds: spectral characteristics, cDNA sequence and retinal localization of the UV-sensitive visual pigment of the budgerigar (Melopsittacus undulatus). Biochemical Journal 330: 541–47.

[33] Andersson, S. (1998). Ultraviolet sexual dimorphism and assortative mating in blue tits. Proceeding of the Royal Society B 265 (1395): 445–50.

[34] Viitala, Jussi (1995). Attraction of kestrels to vole scent marks visible in ultraviolet light. Nature 373 (6513): 425–27.

[35] Williams, David L. (March 2003). Symblepharon with aberrant protrusion of the nictitating membrane in the snowy owl (Nyctea scandiaca). Veterinary Ophthalmology 6 (1): 11–13.

[36] White, Craig R. (July 2007). Vision and Foraging in Cormorants: More like Herons than Hawks?. PLoS ONE 2 (7): e639.

[37] Martin, Graham R. (1999). Visual fields in short-toed eagles, Circaetus gallicus (Accipitridae), and the function of binocularity in birds. Brain, Behaviour and Evolution 53 (2): 55–66.

[38] Saito, Nozomu (1978). Physiology and anatomy of avian ear. The Journal of the Acoustical Society of America 64 (S1): S3.

[39] Warham, John (1 May 1977). The Incidence, Function and ecological significance of petrel stomach oils. Proceedings of the New Zealand Ecological Society 24 (3): 84–93.

[40] Dumbacher, J.P. (October 1992). Homobatrachotoxin in the genus Pitohui: chemical defense in birds?. Science 258 (5083): 799–801.

[41] Göth, Anne (2007). Incubation temperatures and sex ratios in Australian brush-turkey (Alectura lathami) mounds. Austral Ecology 32 (4): 278–85.

[42] Belthoff, James R. (1 August 1994). Plumage Variation, Plasma Steroids and Social Dominance in Male House Finches. The Condor 96 (3): 614–25.

[43] Guthrie, R. Dale How We Use and Show Our Social Organs. Body Hot Spots: The Anatomy of Human Social Organs and Behavior. URL accessed on 2007-10-19.

[44] Humphrey, Philip S. (1 June 1959). An approach to the study of molts and plumages. The Auk 76 (2): 1–31.

[pettingill-45] 45.0 ^45.1 ^45.2 Pettingill Jr. OS (1970). Ornithology in Laboratory and Field, Burgess Publishing Co.

[debeeretal-46] Beer SJ, Lockwood GM, Raijmakers JHFS, Raijmakers JMH, Scott WA, Oschadleus HD, Underhill LG (2001). SAFRING Bird Ringing Manual. SAFRING.

[47] Gargallo, Gabriel (1 June 1994). Flight Feather Moult in the Red-Necked Nightjar Caprimulgus ruficollis. Journal of Avian Biology 25 (2): 119–24.

[48] Mayr, Ernst (1954). The tail molt of small owls. The Auk 71 (2): 172–78.

[49] Payne, Robert B Birds of the World, Biology 532. Bird Division, University of Michigan Museum of Zoology. URL accessed on 2007-10-20.

[50] Turner, J. Scott (July 1997). On the thermal capacity of a bird's egg warmed by a brood patch. Physiological Zoology 70 (4): 470–80.

[51] Walther, Bruno A. (2005). Elaborate ornaments are costly to maintain: evidence for high maintenance handicaps. Behavioural Ecology 16 (1): 89–95.

[52] Shawkey, Matthew D. (2003). Chemical warfare? Effects of uropygial oil on feather-degrading bacteria. Journal of Avian Biology 34 (4): 345–49.

[53] Ehrlich, Paul R. (1986). The Adaptive Significance of Anting. The Auk 103 (4).

[54] Lucas, Alfred M. (1972). Avian Anatomy – integument, 67, 344, 394–601, East Lansing, Michigan, US: USDA Avian Anatomy Project, Michigan State University.

[55] Roots, Clive (2006). Flightless Birds, Westport: Greenwood Press.

[56] McNab, Brian K. (October 1994). Energy Conservation and the Evolution of Flightlessness in Birds. The American Naturalist 144 (4): 628–42.

[57] Kovacs, Christopher E. (May 2000). Anatomy and histochemistry of flight muscles in a wing-propelled diving bird, the Atlantic Puffin, Fratercula arctica. Journal of Morphology 244 (2): 109–25.

[58] Robert, Michel (January 1989). Conditions and significance of night feeding in shorebirds and other water birds in a tropical lagoon. The Auk 106 (1): 94–101.

[59] Paton, D. C. (1 April 1989). Bills and tongues of nectar-feeding birds: A review of morphology, function, and performance, with intercontinental comparisons. Australian Journal of Ecology 14 (4): 473–506.

[60] Baker, Myron Charles (1 April 1973). Niche Relationships Among Six Species of Shorebirds on Their Wintering and Breeding Ranges. Ecological Monographs 43 (2): 193–212.

[61] Cherel, Yves (2002). Food and feeding ecology of the sympatric thin-billed Pachyptila belcheri and Antarctic P. desolata prions at Iles Kerguelen, Southern Indian Ocean. Marine Ecology Progress Series 228: 263–81.

[62] Jenkin, Penelope M. (1957). The Filter-Feeding and Food of Flamingoes (Phoenicopteri). Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 240 (674): 401–93.

[63] Miyazaki, Masamine (1 July 1996). Vegetation cover, kleptoparasitism by diurnal gulls and timing of arrival of nocturnal Rhinoceros Auklets. The Auk 113 (3): 698–702.

[64] Bélisle, Marc (1 August 1995). Predation and kleptoparasitism by migrating Parasitic Jaegers. The Condor 97 (3): 771–781.

[65] Vickery, J. A. (1 May 1994). The Kleptoparasitic Interactions between Great Frigatebirds and Masked Boobies on Henderson Island, South Pacific. The Condor 96 (2): 331–40.

[66] Hiraldo, F.C. (1991). Unspecialized exploitation of small carcasses by birds. Bird Studies 38 (3): 200–07.

[67] Engel, Sophia Barbara (2005). Racing the wind: Water economy and energy expenditure in avian endurance flight, University of Groningen.

[68] Tieleman, B.I. (January 1999). The role of hyperthermia in the water economy of desert birds. Physiol. Biochem. Zool. 72 (1): 87–100.

[69] Schmidt-Nielsen, Knut (1 May 1960). The Salt-Secreting Gland of Marine Birds. Circulation 21 (5): 955–967.

[70] Hallager, Sara L. (1994). Drinking methods in two species of bustards. Wilson Bull. 106 (4): 763–764.

[71] MacLean, Gordon L. (1 June 1983). Water Transport by Sandgrouse. BioScience 33 (6): 365–369.

[Klaassen-72] Klaassen, Marc (1 January 1996). Metabolic constraints on long-distance migration in birds. Journal of Experimental Biology 199 (1): 57–64.

[autogenerated1-73] Gill, Frank (1995). Ornithology, 2nd, New York: W.H. Freeman.

[74] udeonly>"Long-distance Godwit sets new record", BirdLife International, 2007-05-04. Retrieved on 2007-12-13.

[75] Shaffer, Scott A. (August 2006). Migratory shearwaters integrate oceanic resources across the Pacific Ocean in an endless summer. Proceedings of the National Academy of Sciences 103 (34): 12799–802.

[76] Croxall, John P. (January 2005). Global Circumnavigations: Tracking year-round ranges of nonbreeding Albatrosses. Science 307 (5707): 249–50.

[77] Wilson, W. Herbert, Jr. (1999). Bird feeding and irruptions of northern finches:are migrations short stopped?. North America Bird Bander 24 (4): 113–21.

[78] Nilsson, Anna L. K. (2006). Do partial and regular migrants differ in their responses to weather?. The Auk 123 (2): 537–47.

[79] Chan, Ken (2001). Partial migration in Australian landbirds: a review. Emu 101 (4): 281–92.

[80] Rabenold, Kerry N. (1985). Variation in Altitudinal Migration, Winter Segregation, and Site Tenacity in two subspecies of Dark-eyed Juncos in the southern Appalachians. The Auk 102 (4): 805–19.

[81] Collar, Nigel J. (1997). "Family Psittacidae (Parrots)" Josep del Hoyo, Andrew Elliott and Jordi Sargatal (eds.) Handbook of the Birds of the World, Volume 4: Sandgrouse to Cuckoos, Barcelona: Lynx Edicions.

[82] Matthews, G. V. T. (1 September 1953). Navigation in the Manx Shearwater. Journal of Experimental Biology 30 (2): 370–96.

[83] Mouritsen, Henrik (15 November 2001). Migrating songbirds tested in computer-controlled Emlen funnels use stellar cues for a time-independent compass. Journal of Experimental Biology 204 (8): 3855–65.

[84] Deutschlander, Mark E. (15 April 1999). The case for light-dependent magnetic orientation in animals. Journal of Experimental Biology 202 (8): 891–908.

[85] Möller, Anders Pape (1988). Badge size in the house sparrow Passer domesticus. Behavioral Ecology and Sociobiology 22 (5): 373–78.

[86] Thomas, Betsy Trent (1 August 1990). Nesting Behavior of Sunbitterns (Eurypyga helias) in Venezuela. The Condor 92 (3): 576–81.

[87] Pickering, S. P. C. (2001). Courtship behaviour of the Wandering Albatross Diomedea exulans at Bird Island, South Georgia. Marine Ornithology 29 (1): 29–37.

[88] Pruett-Jones, S. G. (1 May 1990). Sexual Selection Through Female Choice in Lawes' Parotia, A Lek-Mating Bird of Paradise. Evolution 44 (3): 486–501.

[89] Genevois, F. (1994). Male Blue Petrels reveal their body mass when calling. Ethology Ecology and Evolution 6 (3): 377–83.

[90] Jouventin, Pierre (June 1999). Finding a parent in a king penguin colony: the acoustic system of individual recognition. Animal Behaviour 57 (6): 1175–83.

[91] Templeton, Christopher N. (June 2005). Allometry of Alarm Calls: Black-Capped Chickadees Encode Information About Predator Size. Science 308 (5730): 1934–37.

[Miskelly-92] Miskelly, C. M. (July 1987). The identity of the hakawai. Notornis 34 (2): 95–116.

[93] Murphy, Stephen (2003). The breeding biology of palm cockatoos (Probosciger aterrimus): a case of a slow life history. Journal of Zoology 261 (4): 327–39.

[flycatcher-94] 94.0 ^94.1 Sekercioglu, Cagan Hakki (2006). "Foreword" Josep del Hoyo, Andrew Elliott and David Christie (eds.) Handbook of the Birds of the World, Volume 11: Old World Flycatchers to Old World Warblers, Barcelona: Lynx Edicions.

[95] Terborgh, John (2005). Mixed flocks and polyspecific associations: Costs and benefits of mixed groups to birds and monkeys. American Journal of Primatology 21 (2): 87–100.

[96] Hutto, Richard L. (1 January 988). Foraging Behavior Patterns Suggest a Possible Cost Associated with Participation in Mixed-Species Bird Flocks. Oikos 51 (1): 79–83.

[AU-97] Au, David W. K. (1 August 1986). Seabird interactions with Dolphins and Tuna in the Eastern Tropical Pacific. The Condor 88 (3): 304–17.

[98] Anne, O. (June 1983). Dwarf mongoose and hornbill mutualism in the Taru desert, Kenya. Behavioral Ecology and Sociobiology 12 (3): 181–90.

[99] Gauthier-Clerc, Michael (May 2000). Sleep-Vigilance Trade-off in Gadwall during the Winter Period. The Condor 102 (2): 307–13.

[100] Bäckman, Johan (1 April 2002). Harmonic oscillatory orientation relative to the wind in nocturnal roosting flights of the swift Apus apus. The Journal of Experimental Biology 205 (7): 905–910.

[101] Rattenborg, Niels C. (September 2006). Do birds sleep in flight?. Die Naturwissenschaften 93 (9): 413–25.

[102] Milius, S. (6 February 1999). Half-asleep birds choose which half dozes. Science News Online 155 (6).

[103] Beauchamp, Guy (1999). The evolution of communal roosting in birds: origin and secondary losses. Behavioural Ecology 10 (6): 675–87.

[104] Buttemer, William A. (1985). Energy relations of winter roost-site utilization by American goldfinches (Carduelis tristis). Oecologia 68 (1): 126–32.

[105] Buckley, F. G. (1 January 1968). Upside-down Resting by Young Green-Rumped Parrotlets (Forpus passerinus). The Condor 70 (1).

[106] Carpenter, F. Lynn (February 1974). Torpor in an Andean Hummingbird: Its Ecological Significance. Science 183 (4124): 545–47.

[107] McKechnie, Andrew E. (2007). Torpor in an African caprimulgid, the freckled nightjar Caprimulgus tristigma. Journal of Avian Biology 38 (3): 261–66.

[108] Frith, C.B. Displays of Count Raggi's Bird-of-Paradise Paradisaea raggiana and congeneric species. Emu 81 (4): 193–201.

[109] Freed, Leonard A. (1987). The Long-Term Pair Bond of Tropical House Wrens: Advantage or Constraint?. The American Naturalist 130 (4): 507–25.

[110] Gowaty, Patricia A. (1983). Male Parental Care and Apparent Monogamy among Eastern Bluebirds (Sialia sialis). The American Naturalist 121 (2): 149–60.

[111] Westneat, David F. (2003). Extra-pair paternity in birds: Causes, correlates, and conflict. Annual Review of Ecology, Evolution, and Systematics 34: 365–96.

[112] Gowaty, Patricia A. (1998). Ultimate causation of aggressive and forced copulation in birds: Female resistance, the CODE hypothesis, and social monogamy. American Zoologist 38 (1): 207–25.

[113] Sheldon, B (1994). Male Phenotype, Fertility, and the Pursuit of Extra-Pair Copulations by Female Birds. Proceedings: Biological Sciences 257 (1348): 25–30.

[114] Wei, G (2005). Copulations and mate guarding of the Chinese Egret. Waterbirds 28 (4): 527–30.

[115] Short, Lester L. (1993). Birds of the World and their Behavior, New York: Henry Holt and Co.

[116] Burton, R (1985). Bird Behavior, Alfred A. Knopf, Inc.

[117] Schamel, D (2004). Mate guarding, copulation strategies and paternity in the sex-role reversed, socially polyandrous red-necked phalarope Phalaropus lobatus. Behaviour Ecology and Sociobiology 57 (2): 110–18.

[118] Kokko H, Harris M, Wanless S (2004). "Competition for breeding sites and site-dependent population regulation in a highly colonial seabird, the common guillemot Uria aalge". Journal of Animal Ecology 73 (2): 367–76.
REDIRECT Template:Doi

[119] REDIRECT Template:Doi

[119] Booker L, Booker M (1991). "Why Are Cuckoos Host Specific?" Oikos 57 (3): 301–09.
REDIRECT Template:Doi

[121] REDIRECT Template:Doi

[Hansell-120] 120.0 ^120.1 Hansell M (2000). Bird Nests and Construction Behaviour. University of Cambridge Press ISBN 0-521-46038-7

[121] Lafuma L, Lambrechts M, Raymond M (2001). "Aromatic plants in bird nests as a protection against blood-sucking flying insects?" Behavioural Processes 56 (2) 113–20.
REDIRECT Template:Doi

[124] REDIRECT Template:Doi

[122] Warham, J. (1990) The Petrels – Their Ecology and Breeding Systems London: Academic Press ISBN 0127354204.

[123] Jones DN, Dekker, René WRJ, Roselaar, Cees S (1995). The Megapodes. Bird Families of the World 3. Oxford University Press: Oxford. ISBN 0-19-854651-3

[124] Elliot A (1994). "Family Megapodiidae (Megapodes)" in Handbook of the Birds of the World. Volume 2; New World Vultures to Guineafowl (eds del Hoyo J, Elliott A, Sargatal J) Lynx Edicions:Barcelona. ISBN 84-873337-15-6

[125] Metz VG, Schreiber EA (2002). "Great Frigatebird (Fregata minor)" In The Birds of North America, No 681, (Poole, A. and Gill, F., eds) The Birds of North America Inc: Philadelphia

[126] Ekman J (2006). "Family living amongst birds". Journal of Avian Biology 37 (4): 289–98.
REDIRECT Template:Doi

[130] REDIRECT Template:Doi

[127] Cockburn A (1996). "Why do so many Australian birds cooperate? Social evolution in the Corvida" Floyd R, Sheppard A, de Barro P Frontiers in Population Ecology, 21–42, Melbourne: CSIRO.

[128] Cockburn, Andrew (June 2006). Prevalence of different modes of parental care in birds. Proceedings: Biological Sciences 273 (1592): 1375–83.

[129] Gaston AJ (1994). Ancient Murrelet (Synthliboramphus antiquus). In The Birds of North America, No. 132 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.

[130] Schaefer HC, Eshiamwata GW, Munyekenye FB, Bohning-Gaese K (2004). "Life-history of two African Sylvia warblers: low annual fecundity and long post-fledging care". Ibis 146 (3): 427–37.
REDIRECT Template:Doi

[135] REDIRECT Template:Doi

[131] Alonso JC, Bautista LM, Alonso JA (2004). "Family-based territoriality vs flocking in wintering common cranes Grus grus". Journal of Avian Biology 35 (5): 434–44.
REDIRECT Template:Doi

[137] REDIRECT Template:Doi

[brood-132] 132.0 ^132.1 Davies N (2000). Cuckoos, Cowbirds and other Cheats. T. & A. D. Poyser: London ISBN 0-85661-135-2

[133] Sorenson M (1997). "Effects of intra- and interspecific brood parasitism on a precocial host, the canvasback, Aythya valisineria". Behavioral Ecology 8 (2) 153–61. PDF

[134] Spottiswoode C, Colebrook-Robjent J (2007). "Egg puncturing by the brood parasitic Greater Honeyguide and potential host counteradaptations". Behavioral Ecology
REDIRECT Template:Doi

[141] REDIRECT Template:Doi

[Clout-135] 135.0 ^135.1 Clout M, Hay J (1989). "The importance of birds as browsers, pollinators and seed dispersers in New Zealand forests". New Zealand Journal of Ecology 12 27–33 PDF

[136] Stiles F (1981). "Geographical Aspects of Bird–Flower Coevolution, with Particular Reference to Central America". Annals of the Missouri Botanical Garden 68 (2) 323–51.
REDIRECT Template:Doi

[144] REDIRECT Template:Doi

[137] Temeles E, Linhart Y, Masonjones M, Masonjones H (2002). "The Role of Flower Width in Hummingbird Bill Length–Flower Length Relationships". Biotropica 34 (1): 68–80. PDF

[138] Bond W, Lee W, Craine J (2004). "Plant structural defences against browsing birds: a legacy of New Zealand's extinct moas". Oikos 104 (3), 500–08.
REDIRECT Template:Doi

[147] REDIRECT Template:Doi

[139] Wainright S, Haney J, Kerr C, Golovkin A, Flint M (1998). "Utilization of nitrogen derived from seabird guano by terrestrial and marine plants at St. Paul, Pribilof Islands, Bering Sea, Alaska". Marine Ecology 131 (1) 63–71. PDF

[140] Bosman A, Hockey A (1986). "Seabird guano as a determinant of rocky intertidal community structure". Marine Ecology Progress Series 32: 247–57 PDF

[141] Bonney, Rick (2004). Handbook of Bird Biology, Second, Princeton University Press.

[142] Dean W, Siegfried R, MacDonald I (1990). "The Fallacy, Fact, and Fate of Guiding Behavior in the Greater Honeyguide". Conservation Biology 4 (1) 99–101. PDF

[143] Singer R, Yom-Tov Y (1988). "The Breeding Biology of the House Sparrow Passer domesticus in Israel". Ornis Scandinavica 19 139–44.
REDIRECT Template:Doi

[153] REDIRECT Template:Doi

[144] Dolbeer R (1990). "Ornithology and integrated pest management: Red-winged blackbirds Agleaius phoeniceus and corn". Ibis 132 (2): 309–22.

[145] Dolbeer R, Belant J, Sillings J (1993). "Shooting Gulls Reduces Strikes with Aircraft at John F. Kennedy International Airport". Wildlife Society Bulletin 21: 442–50.

[146] Routledge S, Routledge K (1917). "The Bird Cult of Easter Island". Folklore 28 (4): 337–55.

[147] Chappell J (2006). "Living with the Trickster: Crows, Ravens, and Human Culture". PLoS Biol 4 (1):e14.
REDIRECT Template:Doi

[158] REDIRECT Template:Doi

[148] Ingersoll, Ernest (1923). "Birds in legend, fable and folklore". Longmans, Green and co. p. 214

[149] Hauser A (1985). "Jonah: In Pursuit of the Dove". Journal of Biblical Literature 104 (1): 21–37.
REDIRECT Template:Doi

[161] REDIRECT Template:Doi

[150] Nair P (1974). "The Peacock Cult in Asia". Asian Folklore Studies 33 (2): 93–170.
REDIRECT Template:Doi

[163] REDIRECT Template:Doi

[151] Tennyson A, Martinson P (2006). Extinct Birds of New Zealand Te Papa Press, Wellington ISBN 978-0-909010-21-8

[152] Meighan C (1966). "Prehistoric Rock Paintings in Baja California". American Antiquity 31 (3): 372–92.
REDIRECT Template:Doi

[166] REDIRECT Template:Doi

[153] Clarke CP (1908). "A Pedestal of the Platform of the Peacock Throne". The Metropolitan Museum of Art Bulletin 3 (10): 182–83.
REDIRECT Template:Doi

[168] REDIRECT Template:Doi

[154] Boime A (1999). "John James Audubon, a birdwatcher's fanciful flights". Art History 22 (5) 728–55.
REDIRECT Template:Doi

[170] REDIRECT Template:Doi

[155] Chandler A (1934). "The Nightingale in Greek and Latin Poetry". The Classical Journal 30 (2): 78–84.

[156] Lasky E (1992). "A Modern Day Albatross: The Valdez and Some of Life's Other Spills". The English Journal, 81 (3): 44–46.
REDIRECT Template:Doi

[173] REDIRECT Template:Doi

[157] Carson A (1998). "Vulture Investors, Predators of the 90s: An Ethical Examination". Journal of Business Ethics 17 (5): 543–55. PDF

[158] Enriquez PL, Mikkola H (1997). "Comparative study of general public owl knowledge in Costa Rica, Central America and Malawi, Africa". pp. 160–66 In: J.R. Duncan, D.H. Johnson, T.H. Nicholls, (Eds). Biology and conservation of owls of the Northern Hemisphere. General Technical Report NC-190, USDA Forest Service, St. Paul, Minnesota. 635 pp.

[159] Lewis DP (2005). Owls in Mythology and Culture. The Owl Pages. Retrieved on 15 September 2007

[160] Dupree N (1974). "An Interpretation of the Role of the Hoopoe in Afghan Folklore and Magic". Folklore 85 (3): 173–93.

[178] REDIRECT Template:Doi

[179] REDIRECT Template:Doi

[180] REDIRECT Template:Doi

[181] REDIRECT Template:Doi

[182] REDIRECT Template:Doi

[183] REDIRECT Template:Doi

[184] REDIRECT Template:Doi

[185] REDIRECT Template:Doi

[186] REDIRECT Template:Doi

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]

[22]

[23]

[24]

[25]

[26]

[27]

[28]

[29]

[30]

[31]

[32]

[33]

[34]

[35]

[36]

[37]

[38]

[39]

[40]

[41]

[42]

[43]

[44]

[45]

[46]

[47]

[48]

[49]

[50]

[51]

[52]

[53]

[54]

[55]

[56]

[57]

[58]

[59]

[60]

[61]

[62]

[63]

[64]

[65]

[66]

[67]

[68]

[69]

[70]

[71]

[72]

[73]

[74]

[75]

[76]

[77]

[78]

[79]

[80]

[81]

[82]

[83]

[84]

[85]

[86]

[87]

[88]

[89]

[90]

[91]

[92]

[93]

[94]

[95]

[96]

[97]

[98]

[99]

[100]

@@ Line 11: / Line 11: @@
 |phylum = [[Chordata]]
 |subphylum = [[Vertebrata]]
-{{Taxobox norank entry | taxon = [[Amniota]]}}
-{{Taxobox norank entry | taxon = [[Diapsida]]}}
-{{Taxobox norank entry | taxon = [[Archosauria]]}}
-{{Taxobox norank entry | taxon = [[Dinosauria]]}}
-{{Taxobox norank entry | taxon = [[Theropoda]]}}
 |classis = '''Aves'''
 |classis_authority = [[Carolus Linnaeus|Linnaeus]], 1758<ref>{{cite web| url= http://www.taxonomy.nl/Main/Classification/51354.htm| title=Systema Naturae 2000 / Classification, Class Aves | accessdate=4 February 2009 | last=Brands | first=Sheila | authorlink= | date=14 Aug 2008 | work=Project: The Taxonomicon }}</ref>
@@ Line 22: / Line 17: @@
 * About two dozen [[#Modern bird orders: Classification|modern orders]] and several [[List of fossil birds|extinct orders and subclasses]]
 }}
-{{Spoken Wikipedia|Bird_(Intro).ogg|2008-01-05}}
-'''Birds''' ([[Class (biology)|class]] '''Aves''') are [[bird flight|wing]]ed, [[Bipedalism|biped]]al, [[Endotherm (biology)|endothermic]] ([[warm-blooded]]), [[egg (biology)|egg-laying]], [[vertebrate]] animals. There are around 10,000 living species, making them the most varied of [[tetrapod]] vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. [[Extant taxon|Extant]] birds range in size from the {{convert|5|cm|in|sigfig=1|abbr=on}} [[Bee Hummingbird]] to the {{convert|2.75|m|ft|sigfig=1|abbr=on}} [[Ostrich]]. The fossil record indicates that birds [[evolution|evolved]] from [[Theropoda|theropod]] [[dinosaur]]s during the [[Jurassic]] period, around 150–200 Ma (million years ago), and the earliest known bird is the Late Jurassic ''[[Archaeopteryx]]'', ''c'' 150–145 Ma. Most [[paleontologist]]s regard birds as the only [[clade]] of dinosaurs to have survived the [[Cretaceous–Tertiary extinction event]] approximately 65.5 Ma.
+'''Birds''' ([[Class (biology)|class]] '''Aves''') are [[bird flight|wing]]ed, [[Bipedalism|biped]]al, [[Endotherm (biology)|endothermic]] ([[warm-blooded]]), [[egg (biology)|egg-laying]], [[vertebrate]] animals. There are around 10,000 living species, making them the most varied of [[tetrapod]] vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. [[Extant taxon|Extant]] birds range in size from the {{convert|5|cm|in|sigfig=1|abbr=on}} [[Bee Hummingbird]] to the {{convert|2.75|m|ft|sigfig=1|abbr=on}} [[Ostrich]]. The fossil record indicates that birds [[evolution|evolved]] from theropod dinosaurs during the Jurassic period, around 150–200 Ma (million years ago), and the earliest known bird is the Late Jurassic ''Archaeopteryx'', ''c'' 150–145 Ma. Most [[paleontologist]]s regard birds as the only [[clade]] of dinosaurs to have survived the Cretaceous–Tertiary extinction event approximately 65.5 Ma.
-Modern birds are [[body plan|characterised]] by [[feather]]s, a [[beak]] with no [[teeth]], the [[Oviposition|laying]] of [[Eggshell|hard-shelled]] eggs, a high [[metabolism|metabolic]] rate, a four-chambered [[heart]], and a lightweight but strong [[Bird skeleton|skeleton]]. All birds have wings, which are [[evolution|evolved]] forelimbs, and most can [[bird flight|fly]], with some exceptions including [[ratite]]s, [[penguin]]s, and a number of diverse [[Endemism in birds|endemic]] island species. Birds also have unique [[digestive system|digestive]] and [[respiratory system]]s that are highly adapted for flight. Some birds, especially [[corvids]] and [[parrots]], are among the most intelligent animal species; a number of bird species have been observed manufacturing and using tools, and many social species exhibit cultural transmission of knowledge across generations.
+Modern birds are [[body plan|characterised]] by [[feather]]s, a [[beak]] with no [[teeth]], the [[Oviposition|laying]] of hard-shelled eggs, a high [[metabolism|metabolic]] rate, a four-chambered [[heart]], and a lightweight but strong [[Bird skeleton|skeleton]]. All birds have wings, which are [[evolution|evolved]] forelimbs, and most can [[bird flight|fly]], with some exceptions including [[ratite]]s, [[penguin]]s, and a number of diverse endemic island species. Birds also have unique [[digestive system|digestive]] and [[respiratory system]]s that are highly adapted for flight. Some birds, especially [[corvids]] and [[parrots]], are among the most intelligent animal species; a number of bird species have been observed manufacturing and using tools, and many social species exhibit cultural transmission of knowledge across generations.
 Many species undertake long distance annual [[bird migration|migrations]], and many more perform shorter irregular movements. Birds are social; they communicate using visual signals and through calls and [[bird song|songs]], and participate in social behaviours including [[Helpers at the nest|cooperative breeding]] and hunting, [[Flocking (behavior)|flocking]], and [[Mobbing behavior|mobbing]] of predators. The vast majority of bird species are [[socially monogamous]], usually for one breeding season at a time, sometimes for years, but rarely for life. Other species have breeding systems that are [[polygyny|polygynous]] ("many females") or, rarely, [[polyandry|polyandrous]] ("many males"). Eggs are usually laid in a nest and [[Avian incubation|incubated]] by the parents. Most birds have an extended period of parental care after hatching.
+==Classification==
-Many species are of economic importance, mostly as sources of food acquired through hunting or farming. Some species, particularly [[songbird]]s and [[parrot]]s, are popular as pets. Other uses include the harvesting of [[guano]] (droppings) for use as a [[fertiliser]]. Birds [[List of fictional birds|figure prominently]] in all aspects of human culture from religion to poetry to popular music. About 120–130 species have become [[extinction|extinct]] as a result of human activity since the 17th century, and hundreds more before then. Currently about 1,200 species of birds are threatened with extinction by human activities, though efforts are underway to [[bird conservation|protect]] them.
+{{Main|Bird families}}
-==Evolution and taxonomy==
-{{Main|Evolution of birds}}
-[[File:Naturkundemuseum Berlin - Archaeopteryx - Eichstätt.jpg|alt= Slab of stone with fossil bones and feather impressions|thumb|right|''[[Archaeopteryx]]'', the earliest known bird]]
-The first [[biological classification|classification]] of birds was developed by [[Francis Willughby]] and [[John Ray]] in their 1676 volume ''Ornithologiae''.<ref>{{cite book  |last=del Hoyo |first=Josep |coauthors=Andy Elliott and Jordi Sargatal |title=[[Handbook of Birds of the World]], Volume 1: Ostrich to Ducks |year=1992 |publisher=[[Lynx Edicions]] |location=Barcelona |isbn=84-87334-10-5}}</ref>
-[[Carolus Linnaeus]] modified that work in 1758 to devise the [[taxonomic classification]] system currently in use.<ref>
-{{la icon}} {{cite book  |last=Linnaeus |first=Carolus |authorlink=Carolus Linnaeus  |title=[[Systema Naturae|Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata]] |publisher=Holmiae. (Laurentii Salvii) |year=1758 |page=824 |url=}}</ref>
-Birds are categorised as the [[Class (biology)|biological class]] Aves in [[Linnaean taxonomy]]. [[Phylogenetic taxonomy]] places Aves in the dinosaur [[clade]] [[Theropoda]].<ref name="Theropoda">{{cite journal |last=Livezey |first=Bradley C. |month=January |year=2007 |title=Higher-order phylogeny of modern birds (Theropoda, Aves: Neornithes) based on comparative anatomy. II. Analysis and discussion |journal=[[Zoological Journal of the Linnean Society]] |volume=149 |issue=1 |pages=1–95 |doi=10.1111/j.1096-3642.2006.00293.x |pmid=18784798 |last1=Livezey |first1=BC |last2=Zusi |first2=RL |issn=0024-4082 |pmc=2517308}}</ref>
-Aves and a sister group, the clade [[Crocodilia]], contain the only living representatives of the [[reptile]] clade [[Archosauria]]. [[Phylogenetics|Phylogenetically]], Aves is commonly defined as all descendants of the [[most recent common ancestor]] of modern birds and ''[[Archaeopteryx|Archaeopteryx lithographica]]''.<ref>{{cite book |last=Padian|first=Kevin|authorlink=Kevin Padian|coauthor=L.M. Chiappe Chiappe LM |editor=[[Philip J. Currie]] and Kevin Padian (eds.) |title=Encyclopedia of Dinosaurs|year=1997|publisher=[[Academic Press]]|location=San Diego|pages=41–96|chapter=Bird Origins|isbn=0-12-226810-5}}</ref>
-''Archaeopteryx'', from the [[Tithonian]] stage of the [[Late Jurassic]] (some {{Nowrap|150–145 million}} years ago), is the earliest known bird under this definition. Others, including [[Jacques Gauthier]] and adherents of the [[Phylocode]] system, have defined Aves to include only the modern bird groups, the [[crown group]]. This has been done by excluding most groups known only from fossils, and assigning them, instead, to the [[Avialae]]<ref>{{cite book |last=Gauthier |first=Jacques|editor=Kevin Padian |title=The Origin of Birds and the Evolution of Flight|series= Memoirs of the California Academy of Science '''8'''|year=1986|pages=1–55|chapter=Saurischian Monophyly and the origin of birds|isbn=0-940228-14-9 |publisher=Published by California Academy of Sciences |location=San Francisco, CA}}</ref> in part to avoid the uncertainties about the placement of ''Archaeopteryx'' in relation to animals traditionally thought of as theropod dinosaurs.<!-- See WP:RS<ref>http://www.phylonames.org/forum/viewtopic.php?t=7</ref> --><!--Mayr et al. 2005 "A well-preserved Archaeopteryx specimen with theropod features" + comment + Mayr's comment on the comment-->
-All modern birds lie within the [[subclass (biology)|subclass]] [[Neornithes]], which has two subdivisions: the [[Palaeognathae]], containing birds that are flightless (like [[ostrich]]es) or weak fliers, and the wildly diverse [[Neognathae]], containing all other birds.<ref name="Theropoda"/> These two subdivisions are often given the [[taxonomic rank|rank]] of [[superorder]],<ref>{{cite web |url=http://people.eku.edu/ritchisong/birdbiogeography1.htm |title=Bird biogeography |accessdate=2008-04-10 |work=}}</ref> although Livezey and Zusi assigned them "cohort" rank.<ref name="Theropoda"/> Depending on the [[alpha taxonomy|taxonomic]] viewpoint, the number of known living bird species varies anywhere from 9,800<ref>{{cite book |title=[[The Clements Checklist of Birds of the World]] |first=James F. |last=Clements |edition=6th |authorlink=James Clements |location=Ithaca |publisher=[[Cornell University Press]] |year=2007 |isbn=978-0-8014-4501-9
- }}</ref> to 10,050.<ref>{{cite book |last=Gill |first=Frank |authorlink=Frank Gill (ornithologist) |year=2006 |title=Birds of the World: Recommended English Names |location=Princeton |publisher=[[Princeton University Press]] |isbn=978-0-691-12827-6}}</ref>
-===Dinosaurs and the origin of birds===
-{{Main|Origin of birds}}
-[[File:Confuchisornis sanctus.JPG|thumb|alt= White slab of rock left with cracks and impression of bird feathers and bone, including long paired tail feathers|''[[Confuciusornis]]'', a Cretaceous bird from China]]
-Based on fossil and biological evidence, most scientists accept that birds are a specialised sub-group of [[Theropoda|theropod]] [[Dinosauria|dinosaurs]].<ref>{{cite journal|last=Prum|first=Richard O. Prum|title=Who's Your Daddy|journal=Science|volume=322|pages=1799–1800|year=2008|doi=10.1126/science.1168808|pmid=19095929|month= December|issue=5909|issn=0036-8075}}</ref> More specifically, they are members of [[Maniraptora]], a group of theropods which includes [[dromaeosaur]]s and [[Oviraptoridae|oviraptorids]], among others.<ref>{{cite book |last=Paul |first=Gregory S. |authorlink=Gregory S. Paul |chapter=Looking for the True Bird Ancestor |year=2002 |title=Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds |location=Baltimore
-|publisher=John Hopkins University Press |isbn=0-8018-6763-0
-|pages=171–224}}</ref> As scientists discover more non-avian theropods that are closely related to birds, the previously clear distinction between non-birds and birds has become blurred. Recent discoveries in the [[Liaoning]] Province of northeast China, which demonstrate that many small [[Feathered dinosaurs|theropod dinosaurs had feathers]], contribute to this ambiguity.<ref>{{cite book |last=Norell |first=Mark |coauthors=Mick Ellison |year=2005 |title=Unearthing the Dragon: The Great Feathered Dinosaur Discovery |location=New York
-|publisher=Pi Press |isbn=0-13-186266-9|pages=}}</ref>
-The consensus view in contemporary [[paleontology]] is that the birds, Aves, are the closest relatives of the [[deinonychosaur]]s, which include [[dromaeosaurid]]s and [[troodontid]]s. Together, these three form a group called [[Paraves]]. The [[basal (phylogenetics)|basal]] dromaeosaur ''[[Microraptor]]'' has features which may have enabled it to glide or fly. The most basal deinonychosaurs are very small. This evidence raises the possibility that the ancestor of all paravians may have been [[arboreal]], may have been able to glide, or both.<ref name="AHTetal07">{{cite journal |last=Turner |first=Alan H. |year=2007 |title=A basal dromaeosaurid and size evolution preceding avian flight |url=http://www.sciencemag.org/cgi/reprint/317/5843/1378.pdf |format=PDF |journal=[[Science (journal)|Science]]|volume=317 |pages=1378–1381 |doi=10.1126/science.1144066 |pmid=17823350 |month= September|issue=5843 |issn=0036-8075 |last2=Pol |first2=D |last3=Clarke |first3=JA |last4=Erickson |first4=GM |last5=Norell |first5=MA }}</ref><ref name="xuetal2003">{{cite journal|author=Xing, X., Zhou, Z., Wang, X., Kuang, X., Zhang, F., and Du, X.|year=2003|title=Four-winged dinosaurs from China|journal=[[Nature (journal)|Nature]]|volume=421|issue=6921|pages=335–340|doi=10.1038/nature01342|pmid=12540892|month= January|last1=Xu|first1=X|last2=Zhou|first2=Z|last3=Wang|first3=X|last4=Kuang|first4=X|last5=Zhang|first5=F|last6=Du|first6=X|issn=0028-0836}}</ref>
-The [[Late Jurassic]] ''[[Archaeopteryx]]'' is well-known as one of the first [[transitional fossil]]s to be found and it provided support for the theory of [[evolution]] in the late 19th century. ''Archaeopteryx'' has clearly reptilian characteristics: teeth, clawed fingers, and a long, lizard-like tail, but it has finely preserved wings with flight feathers identical to those of modern birds. It is not considered a direct ancestor of modern birds, but is the oldest and most primitive known member of [[Aves]] or [[Avialae]], and it is probably closely related to the real ancestor.<ref name ="mayretal2007">Mayr, G., Phol, B., Hartman, S. and Peters, D.S. (2007). "The tenth skeletal specimen of ''Archaeopteryx''." ''Zoological Journal of the Linnean Society'', '''149''': 97–116.</ref>
-===Alternative theories and controversies===
-There have been many controversies in the study of the origin of birds. Early disagreements included whether birds evolved from [[dinosaur]]s or more primitive [[archosaur]]s. Within the dinosaur camp there were disagreements as to whether [[ornithischia]]n or [[theropod]] dinosaurs were the more likely ancestors.<ref name="Heilmann1927">Heilmann, Gerhard (1927). ''The Origin of Birds''. New York: Dover Publications.</ref> Although ornithischian (bird-hipped) dinosaurs share the hip structure of modern birds, birds are thought to have originated from the [[saurischia]]n (lizard-hipped) dinosaurs, and therefore evolved their hip structure [[Convergent evolution|independently]].<ref>{{cite journal |last=Rasskin-Gutman |first=Diego |month=March |year=2001 |title=Theoretical morphology of the Archosaur (Reptilia: Diapsida) pelvic girdle |journal=[[Paleobiology (journal)|Paleobiology]] |volume=27 |issue=1 |pages=59–78|doi=10.1666/0094-8373(2001)027<0059:TMOTAR>2.0.CO;2 |last2=Buscalioni |first2=Angela D.}}</ref> In fact, a bird-like hip structure evolved a third time among a peculiar group of theropods known as the [[Therizinosauridae]]. A few scientists suggest that birds are not dinosaurs, but evolved from early archosaurs like ''[[Longisquama]]''.<ref>{{cite journal |last=Feduccia |first=Alan |month=November |year=2005|title=Do feathered dinosaurs exist? Testing the hypothesis on neontological and paleontological evidence |journal=Journal of Morphology |volume=266 |issue=2 |pages=125–66 |doi=10.1002/jmor.10382 |pmid=16217748 |issn=0362-2525 |last2=Lingham-Soliar |first2=T |last3=Hinchliffe |first3=JR}}</ref><ref>This theory is contested by most [[palaeontology|paleontologists]] {{cite journal |last=Prum |first=Richard O. |month=April |year=2003 |title=Are Current Critiques Of The Theropod Origin Of Birds Science? Rebuttal To Feduccia 2002
-|journal=[[The Auk]] |volume=120 |issue=2 |pages=550–61
-|url=http://links.jstor.org/sici?sici=0004-8038(200304)120:2%3C550:ACCOTT%3E2.0.CO;2-0 |doi=10.1642/0004-8038(2003)120[0550:ACCOTT]2.0.CO;2}}</ref>
-===Early evolution of birds===
-{{See also|List of fossil birds}}
-{{userboxtop| toptext=&nbsp;}}
-{{clade|style=font-size:75%
-|label1=Aves&nbsp;
-|1={{clade
-   |1=''[[Archaeopteryx]]''
-   |label2=&nbsp;[[Pygostylia]]&nbsp;
-   |2={{clade
-      |1=[[Confuciusornithidae]]
-      |label2=&nbsp;[[Ornithothoraces]]&nbsp;
-      |2={{clade
-          |1=[[Enantiornithes]]
-         |label2=&nbsp;[[Ornithurae]]&nbsp;
-         |2={{clade
-            |1=[[Hesperornithiformes]]
-            |2=[[Neornithes]]
-       }}
-       }}
-    }}
-   }}
-}}
-<center><small>Basal bird phylogeny simplified after Chiappe, 2007<ref name="chiappe2007">{{cite book |last=Chiappe |first=Luis M. |year=2007 |title=Glorified Dinosaurs: The Origin and Early Evolution of Birds |location=Sydney |publisher=University of New South Wales Press |isbn=978-0-86840-413-4}}</ref></small></center>
-{{userboxbottom}}
-Birds diversified into a wide variety of forms during the [[Cretaceous Period]].<ref name="chiappe2007"/> Many groups retained [[symplesiomorphy|primitive characteristics]], such as clawed wings and teeth, though the latter were lost independently in a number of bird groups, including [[modern birds]] (Neornithes). While the earliest forms, such as ''Archaeopteryx'' and ''[[Jeholornis]]'', retained the long bony tails of their ancestors,<ref name="chiappe2007"/> the tails of more advanced birds were shortened with the advent of the [[pygostyle]] bone in the [[clade]] Pygostylia.
-The first large, diverse lineage of short-tailed birds to evolve were the [[Enantiornithes]], or "opposite birds", so named because the construction of their shoulder bones was in reverse to that of modern birds. Enantiornithes occupied a wide array of ecological niches, from sand-probing shorebirds and fish-eaters to tree-dwelling forms and seed-eaters.<ref name="chiappe2007"/> More advanced lineages also specialised in eating fish, like the superficially [[gull]]-like subclass of [[Ichthyornithes]] ("fish birds").<ref>
-{{cite journal |last=Clarke |first=Julia A. |coauthors= |month=September |year=2004 |title=Morphology, Phylogenetic Taxonomy, and Systematics of ''Ichthyornis'' and ''Apatornis'' (Avialae: Ornithurae) |journal=Bulletin of the American Museum of Natural History |volume=286 |pages=1–179 |doi= 10.1206/0003-0090(2004)286<0001:MPTASO>2.0.CO;2|url=http://digitallibrary.amnh.org/dspace/bitstream/2246/454/1/B286.pdf|format=PDF}}</ref>
-One order of Mesozoic seabirds, the [[Hesperornithiformes]], became so well adapted to hunting fish in marine environments that they lost the ability to fly and became primarily aquatic. Despite their extreme specialisations, the Hesperornithiformes represent some of the closest relatives of modern birds.<ref name="chiappe2007"/>
-===Radiation of modern birds===
-{{See also|Sibley-Ahlquist taxonomy|dinosaur classification}}
-Containing all modern birds, the subclass Neornithes is, due to the discovery of ''[[Vegavis]]'', now known to have evolved into some basic lineages by the end of the Cretaceous<!--see also Historical Biology 18:205--><ref>{{cite journal |last=Clarke |first=Julia A. |month=January |year=2005 |title=Definitive fossil evidence for the extant avian radiation in the Cretaceous |journal=[[Nature (journal)|Nature]] |volume=433 |issue= 7023|pages=305–308 |doi=10.1038/nature03150 |pmid=15662422 |url=http://www.digimorph.org/specimens/Vegavis_iaai/nature03150.pdf|format=PDF |issn=0028-0836 |last2=Tambussi |first2=CP |last3=Noriega |first3=JI |last4=Erickson |first4=GM |last5=Ketcham |first5=RA}} [http://www.nature.com/nature/journal/v433/n7023/suppinfo/nature03150.html Supporting information]</ref> and is split into two superorders, the [[Palaeognathae]] and [[Neognathae]]. The paleognaths include the [[tinamou]]s of [[Central America|Central]] and South America and the [[ratite]]s. The basal divergence from the remaining Neognathes was that of the [[Galloanserae]], the superorder containing the [[Anseriformes]] ([[duck]]s, [[goose|geese]], [[swan]]s and [[screamer]]s) and the [[Galliformes]] (the [[pheasant]]s, [[grouse]], and their allies, together with the [[mound builder (bird)|mound builders]] and the [[guan (bird)|guan]]s and their allies). The dates for the splits are much debated by scientists. It is agreed that the Neornithes evolved in the Cretaceous, and that the split between the Galloanseri from other Neognathes occurred before the [[Cretaceous–Tertiary extinction event|K–T extinction event]], but there are different opinions about whether the [[Evolutionary radiation|radiation]] of the remaining Neognathes occurred before or after the extinction of the other dinosaurs.<ref name="Ericson">{{cite journal |last=Ericson |first=Per G.P. |month=December |year=2006 |title=Diversification of Neoaves: Integration of molecular sequence data and fossils |journal=[[Biology Letters]] |volume=2 |issue=4 |pages=543–547 |doi=10.1098/rsbl.2006.0523 |pmid=17148284 |url=http://www.senckenberg.de/files/content/forschung/abteilung/terrzool/ornithologie/neoaves.pdf|format=PDF |issn=1744-9561 |last2=Anderson |first2=CL |last3=Britton |first3=T |last4=Elzanowski |first4=A |last5=Johansson |first5=US |last6=Källersjö |first6=M |last7=Ohlson |first7=JI |last8=Parsons |first8=TJ |last9=Zuccon |first9=D |pmc=1834003}}</ref> This disagreement is in part caused by a divergence in the evidence; molecular dating suggests a Cretaceous radiation, while [[fossil]] evidence supports a [[Tertiary]] radiation. Attempts to reconcile the molecular and fossil evidence have proved controversial.<ref name="Ericson"/><ref>{{cite journal |last=Brown |first=Joseph W. |month=June |year=2007 |title=Nuclear DNA does not reconcile 'rocks' and 'clocks' in Neoaves: a comment on Ericson ''et al.'' |journal=[[Biology Letters]] |volume=3 |issue=3 |pages=257–259 |doi=10.1098/rsbl.2006.0611 |pmid=17389215 |issn=1744-9561 |url=http://rsbl.royalsocietypublishing.org/cgi/pmidlookup?view=long&pmid=17389215 |format=Free full text |last2=Payne |first2=RB |last3=Mindell |first3=DP |pmc=2464679}}</ref>
 The classification of birds is a contentious issue. [[Charles Sibley|Sibley]] and [[Jon Ahlquist|Ahlquist]]'s ''Phylogeny and Classification of Birds'' (1990) is a landmark work on the classification of birds,<ref>{{cite book |last=Sibley |first=Charles |authorlink=Charles Sibley |coauthors=[[Jon Edward Ahlquist]] |year=1990 |title=Phylogeny and classification of birds |location=New Haven |publisher=Yale University Press |isbn=0-300-04085-7}}</ref> although it is frequently debated and constantly revised. Most evidence seems to suggest that the assignment of orders is accurate,<ref>{{cite book |last=Mayr |first=Ernst |authorlink=Ernst W. Mayr |coauthors=Short, Lester L.|title=Species Taxa of North American Birds: A Contribution to Comparative Systematics |series=Publications of the Nuttall Ornithological Club, no. 9 |year=1970 |publisher=Nuttall Ornithological Club|location=Cambridge, Mass. |oclc=517185}}</ref> but scientists disagree about the relationships between the orders themselves; evidence from modern bird anatomy, fossils and DNA have all been brought to bear on the problem, but no strong consensus has emerged. More recently, new fossil and molecular evidence is providing an increasingly clear picture of the evolution of modern bird orders.
@@ Line 103: / Line 32: @@
 <!--<div style="align:right; float:right;" border=1>-->
-{{userboxtop| toptext=&nbsp;}}
 {{clade
 |label1=Neornithes&nbsp;&nbsp;
@@ Line 126: / Line 55: @@
 <center><small>Basal divergences of modern birds<br/>based on [[Sibley-Ahlquist taxonomy]]</small></center>
 <!--</div>-->
-{{userboxbottom}}
-[[File:Neoaves Alternative Cladogram.png|thumb|300px||right|Cladogram showing the most recent classification of Neoaves, based on several phylogenetic studies.<ref>[http://tolweb.org/Neoaves/26305 "Neoaves"], ''Tree of Life Project''</ref>]]
-This is a list of the taxonomic orders in the subclass Neornithes, or modern birds. This list uses the traditional classification (the so-called [[James Clements|Clements]] order), revised by the Sibley-Monroe classification. The [[list of birds]] gives a more detailed summary of the orders, including families.
-'''Subclass Neornithes'''<br/>
-The subclass Neornithes has two [[superorder]]s&nbsp;–
-Superorder [[Palaeognathae]]:
-The name of the superorder is derived from 'paleognath', the ancient Greek for "old jaws" in reference to the skeletal anatomy of the palate, which is described as more primitive and reptilian than that in other birds. The Palaeognathae consists of two orders which comprise 49 existing species.
-* [[Struthioniformes]]—[[ostrich]]es, [[emu]]s, [[kiwi]]s, and allies
-* [[Tinamiformes]]—tinamous
-Superorder [[Neognathae]]:
-The superorder Neognathae comprises 27 orders which have a total of nearly ten thousand species.
-The Neognathae have undergone [[adaptive radiation]] to produce the staggering diversity of form (especially of the bill and feet), function, and behavior that are seen today.
-The orders comprising the Neognathae are:
-* [[Anseriformes]]—waterfowl
-* [[Galliformes]]—fowl
-* [[Charadriiformes]]—[[gull]]s, [[button-quail]]s, [[plover]]s and allies
-* [[Gaviiformes]]—loons
-* [[Podicipediformes]]—grebes
-* [[Procellariiformes]]—[[albatross]]es, [[petrel]]s, and allies
-* [[Sphenisciformes]]—penguins
-* [[Pelecaniformes]]—[[pelican]]s and allies
-* [[Phaethontiformes]]—tropicbirds
-* [[Ciconiiformes]]—[[stork]]s and allies
-* [[Cathartiformes]]—New World vultures
-* [[Phoenicopteriformes]]—flamingos
-* [[Falconiformes]]—[[falcon]]s, [[eagle]]s, [[hawk]]s and allies
-* [[Gruiformes]]—[[Crane (bird)|cranes]] and allies
-* [[Pteroclidiformes]]—sandgrouse
-* [[Columbiformes]]—[[Columbidae|doves and pigeons]]
-* [[parrot|Psittaciformes]]—[[parrot]]s and allies
-* [[Cuculiformes]]—[[cuckoo]]s and [[turaco]]s
-* [[Opisthocomiformes]]—hoatzin
-* [[owl|Strigiformes]]—owls
-* [[Caprimulgiformes]]—[[nightjar]]s and allies
-* [[Apodiformes]]—[[swift]]s and [[hummingbird]]s
-* [[Coraciiformes]]—[[kingfisher]]s and allies
-* [[Piciformes]]—[[woodpecker]]s and allies
-* [[Trogoniformes]]—trogons
-* [[Coliiformes]]—mousebirds
-* [[Passerine|Passeriformes]]—passerines
-The radically different Sibley-Monroe classification ([[Sibley-Ahlquist taxonomy]]), based on molecular data, found widespread adoption in a few aspects, as recent molecular, fossil, and anatomical evidence supported the [[Galloanserae]].<ref name = "Ericson"/>
-==Distribution==
-[[File:House sparrow04.jpg|thumb|left|alt= small bird withpale belly and breast and patterned wing and head stands on concrete |The range of the [[House Sparrow]] has expanded dramatically due to human activities.<ref>{{cite book|last=Newton |first=Ian|year=2003 |title=The Speciation and Biogeography of Birds |location=Amsterdam |publisher=Academic Press |isbn=0-12-517375-X|page=463}}</ref>]]
 Birds live and breed in most terrestrial habitats and on all seven continents, reaching their southern extreme in the [[Snow Petrel|Snow Petrel's]] breeding colonies up to {{convert|440|km|mi|-1}} inland in [[Antarctica]].<ref>{{cite book |last=Brooke |first=Michael |year=2004 |title=Albatrosses And Petrels Across The World |location=Oxford |publisher=Oxford University Press|isbn=0-19-850125-0|pages=}}</ref> The highest bird [[biodiversity|diversity]] occurs in tropical regions. It was earlier thought that this high diversity was the result of higher [[speciation]] rates in the tropics, however recent studies found higher speciation rates in the high latitudes that were offset by greater [[extinction]] rates than in the tropics.<ref>{{cite journal |last=Weir |first=Jason T. |month=March |year=2007 |title=The Latitudinal Gradient in Recent Speciation and Extinction Rates of Birds and Mammals |journal=[[Science (journal)|Science]] |volume=315 |issue=5818 |pages=1574–76 |doi=10.1126/science.1135590 |pmid=17363673 |issn=0036-8075 |last2=Schluter |first2=D}}</ref> Several families of birds have adapted to life both on the world's oceans and in them, with some [[seabird]] species coming ashore only to breed<ref name = "Burger">{{cite book |last=Schreiber |first=Elizabeth Anne |coauthors=Joanna Burger |year=2001 |title=Biology of Marine Birds |location=Boca Raton |publisher=CRC Press |isbn=0-8493-9882-7|pages=}}</ref> and some [[penguin]]s have been recorded diving up to {{convert|300|m|ft|-1}}.<ref>{{cite journal |last=Sato |first=Katsufumi |date=1 May 2002|title=Buoyancy and maximal diving depth in penguins: do they control inhaling air volume? |journal=Journal of Experimental Biology |volume=205 |issue=9 |pages=1189–1197 |pmid=11948196 |url=http://jeb.biologists.org/cgi/content/full/205/9/1189 |issn=0022-0949 |author2=N |author3=K |author4=N |author5=W |author6=C |author7=B |author8=H |author9=L}}</ref>
@@ Line 272: / Line 146: @@
 [[File:Caribbean Flamingo2 (Phoenicopterus ruber) (0424) - Relic38.jpg|thumb|alt= Pink flamingo with grey legs and long neck pressed against body and head tucked under wings|Many birds, like this [[American Flamingo]], tuck their head into their back when sleeping]]
-The high metabolic rates of birds during the active part of the day is supplemented by rest at other times. Sleeping birds often use a type of sleep known as vigilant sleep, where periods of rest are interspersed with quick eye-opening 'peeks', allowing them to be sensitive to disturbances and enable rapid escape from threats.<ref>{{cite journal |last=Gauthier-Clerc |first=Michael |month=May |year=2000 |title=Sleep-Vigilance Trade-off in Gadwall during the Winter Period |journal=The Condor |volume=102 |issue=2 |pages=307–13 |url=http://elibrary.unm.edu/sora/Condor/files/issues/v102n02/p0307-p0313.pdf |doi=10.1650/0010-5422(2000)102[0307:SVTOIG]2.0.CO;2|format=PDF |last2=Tamisier |first2=Alain |last3=Cézilly |first3=Frank}}</ref> [[Swift]]s are believed to be able to sleep in flight and radar observations suggest that they orient themselves to face the wind in their roosting flight.<ref>{{cite journal|journal=The Journal of Experimental Biology|volume=205|pages=905&ndash;910|date=1 April 2002|title=Harmonic oscillatory orientation relative to the wind in nocturnal roosting flights of the swift ''Apus apus''|first=Johan|last=Bäckman|url=http://jeb.biologists.org/cgi/content/full/205/7/905|pmid=11916987|issue=7|issn=0022-0949|author2=A}}</ref> It has been suggested that there may be certain kinds of sleep which are possible even when in flight.<ref>{{cite journal|last=Rattenborg|first=Niels C. |year=2006 |title=Do birds sleep in flight? |journal=Die Naturwissenschaften |volume=93 |issue=9 |pages=413–25 |doi=10.1007/s00114-006-0120-3|pmid=16688436|month= September|last1=Rattenborg|first1=NC|issn=0028-1042}}</ref> Some birds have also demonstrated the capacity to fall into [[slow-wave sleep]] one [[Cerebral hemisphere|hemisphere]] of the brain at a time. The birds tend to exercise this ability depending upon its position relative to the outside of the flock. This may allow the eye opposite the sleeping hemisphere to remain vigilant for [[predator]]s by viewing the outer margins of the flock. This adaptation is also known from [[marine mammal]]s.<ref>{{cite journal |last=Milius |first=S. |date=6 February 1999|title=Half-asleep birds choose which half dozes |journal=Science News Online |volume=155 |issue= 6|page=86 |url=http://findarticles.com/p/articles/mi_m1200/is_6_155/ai_53965042 |doi=10.2307/4011301 |issn=00368423 }}</ref> Communal roosting is common because it lowers the [[thermoregulation|loss of body heat]] and decreases the risks associated with predators.<ref>{{cite journal |last=Beauchamp |first=Guy |year=1999 |title=The evolution of communal roosting in birds: origin and secondary losses |journal=Behavioural Ecology |volume=10 |issue=6 |pages=675–87 |url=http://beheco.oxfordjournals.org/cgi/content/full/10/6/675 |doi=10.1093/beheco/10.6.675 }}</ref> Roosting sites are often chosen with regard to thermoregulation and safety.<ref>{{cite journal |last=Buttemer |first=William A.|year=1985 |title=Energy relations of winter roost-site utilization by American goldfinches (''Carduelis tristis'') |journal=[[Oecologia]] |volume=68 |issue=1 |pages=126–32 |url=http://deepblue.lib.umich.edu/bitstream/2027.42/47760/1/442_2004_Article_BF00379484.pdf |doi=10.1007/BF00379484 |format=PDF}}</ref>
+The high metabolic rates of birds during the active part of the day is supplemented by rest at other times. Sleeping birds often use a type of sleep known as vigilant sleep, where periods of rest are interspersed with quick eye-opening 'peeks', allowing them to be sensitive to disturbances and enable rapid escape from threats.<ref>{{cite journal |last=Gauthier-Clerc |first=Michael |month=May |year=2000 |title=Sleep-Vigilance Trade-off in Gadwall during the Winter Period |journal=The Condor |volume=102 |issue=2 |pages=307–13 |url=http://elibrary.unm.edu/sora/Condor/files/issues/v102n02/p0307-p0313.pdf |doi=10.1650/0010-5422(2000)102[0307:SVTOIG]2.0.CO;2|format=PDF |last2=Tamisier |first2=Alain |last3=Cézilly |first3=Frank}}</ref> [[Swift]]s are believed to be able to sleep in flight and radar observations suggest that they orient themselves to face the wind in their roosting flight.<ref>{{cite journal|journal=The Journal of Experimental Biology|volume=205|pages=905&ndash;910|date=1 April 2002|title=Harmonic oscillatory orientation relative to the wind in nocturnal roosting flights of the swift ''Apus apus''|first=Johan|last=Bäckman|url=http://jeb.biologists.org/cgi/content/full/205/7/905|pmid=11916987|issue=7|issn=0022-0949|author2=A}}</ref> It has been suggested that there may be certain kinds of sleep which are possible even when in flight.<ref>{{cite journal|last=Rattenborg|first=Niels C. |year=2006 |title=Do birds sleep in flight? |journal=Die Naturwissenschaften |volume=93 |issue=9 |pages=413–25 |doi=10.1007/s00114-006-0120-3|pmid=16688436|month= September|last1=Rattenborg|first1=NC|issn=0028-1042}}</ref> Some birds have also demonstrated the capacity to fall into [[slow-wave sleep]] one [[Cerebral hemisphere|hemisphere]] of the brain at a time. The birds tend to exercise this ability depending upon its position relative to the outside of the flock. This may allow the eye opposite the sleeping hemisphere to remain vigilant for [[predator]]s by viewing the outer margins of the flock. This adaptation is also known from [[marine mammal]]s.<ref>{{cite journal |last=Milius |first=S. |date=6 February 1999|title=Half-asleep birds choose which half dozes |journal=Science News Online |volume=155 |issue= 6|page=86 |url=http://findarticles.com/p/articles/mi_m1200/is_6_155/ai_53965042 |doi=10.2307/4011301 |issn=00368423 |archiveurl=http://archive.is/QfKO|archivedate=2012-05-29}}</ref> Communal roosting is common because it lowers the [[thermoregulation|loss of body heat]] and decreases the risks associated with predators.<ref>{{cite journal |last=Beauchamp |first=Guy |year=1999 |title=The evolution of communal roosting in birds: origin and secondary losses |journal=Behavioural Ecology |volume=10 |issue=6 |pages=675–87 |url=http://beheco.oxfordjournals.org/cgi/content/full/10/6/675 |doi=10.1093/beheco/10.6.675 }}</ref> Roosting sites are often chosen with regard to thermoregulation and safety.<ref>{{cite journal |last=Buttemer |first=William A.|year=1985 |title=Energy relations of winter roost-site utilization by American goldfinches (''Carduelis tristis'') |journal=[[Oecologia]] |volume=68 |issue=1 |pages=126–32 |url=http://deepblue.lib.umich.edu/bitstream/2027.42/47760/1/442_2004_Article_BF00379484.pdf |doi=10.1007/BF00379484 |format=PDF}}</ref>
 Many sleeping birds bend their heads over their backs and tuck their [[beak|bills]] in their back feathers, although others place their beaks among their breast feathers. Many birds rest on one leg, while some may pull up their legs into their feathers, especially in cold weather. [[Passerine|Perching birds]] have a tendon locking mechanism that helps them hold on to the perch when they are asleep. Many ground birds, such as quails and pheasants, roost in trees. A few parrots of the genus ''[[Loriculus]]'' roost hanging upside down.<ref>{{cite journal |last=Buckley |first=F. G. |date=1 January 1968|title=Upside-down Resting by Young Green-Rumped Parrotlets (''Forpus passerinus'') |journal=The Condor |volume=70 |issue=1 |page=89 |doi=10.2307/1366517 |issn=00105422 |author2=Buckley}}</ref> Some [[hummingbird]]s go into a nightly state of [[torpor]] accompanied with a reduction of their metabolic rates.<ref>{{cite journal |last=Carpenter |first=F. Lynn |year=1974 |title=Torpor in an Andean Hummingbird: Its Ecological Significance |journal=Science |volume=183 |issue=4124 |pages=545–47 |doi=10.1126/science.183.4124.545 |pmid=17773043 |month= February|issn=0036-8075}}</ref> This [[Adaptation|physiological adaptation]] shows in nearly a hundred other species, including [[owlet-nightjar]]s, [[nightjar]]s, and [[woodswallow]]s. One species, the [[Common Poorwill]], even enters a state of [[hibernation]].<ref>{{cite journal |last=McKechnie |first=Andrew E. |year=2007 |title=Torpor in an African caprimulgid, the freckled nightjar ''Caprimulgus tristigma'' |journal=Journal of Avian Biology |volume=38 |issue=3 |pages=261–66 |doi=10.1111/j.2007.0908-8857.04116.x |last2=Ashdown |first2=Robert A. M. |last3=Christian |first3=Murray B. |last4=Brigham |first4=R. Mark}}</ref> Birds do not have sweat glands, but they may cool themselves by moving to shade, standing in water, panting, increasing their surface area, fluttering their throat or by using special behaviours like [[urohidrosis]] to cool themselves.
@@ Line 326: / Line 200: @@
 Since birds are highly visible and common animals, humans have had a relationship with them since the dawn of man.<ref>{{Cite book|last=Bonney|first=Rick | last2 = Rohrbaugh, Jr.| first2 = Ronald|title=Handbook of Bird Biology| place= Princeton, NJ|publisher=Princeton University Press|year=2004| edition = Second|isbn=0-938-02762-X}}</ref> Sometimes, these relationships are [[Mutualism (biology)|mutualistic]], like the cooperative honey-gathering among [[honeyguide]]s and African peoples such as the [[Borana people|Borana]].<ref>Dean W, Siegfried R, MacDonald I (1990). "The Fallacy, Fact, and Fate of Guiding Behavior in the Greater Honeyguide". ''Conservation Biology'' '''4''' (1) 99–101. [http://www.blackwell-synergy.com/doi/abs/10.1111/j.1523-1739.1990.tb00272.x PDF]</ref> Other times, they may be [[Commensalism|commensal]], as when species such as the [[House Sparrow]]<ref>Singer R, Yom-Tov Y (1988). "The Breeding Biology of the House Sparrow ''Passer domesticus'' in Israel". ''[[Ornis Scandinavica]]'' '''19''' 139–44. {{DOI|10.2307/3676463}}</ref> have benefited from human activities. Several bird species have become commercially significant agricultural pests,<ref>Dolbeer R (1990). "Ornithology and integrated pest management: Red-winged blackbirds ''Agleaius phoeniceus'' and corn". ''[[Ibis (journal)|Ibis]]'' '''132''' (2): 309–22.</ref> and some pose an [[bird strike|aviation hazard]].<ref>Dolbeer R, Belant J, Sillings J (1993). "Shooting Gulls Reduces Strikes with Aircraft at John F. Kennedy International Airport". ''Wildlife Society Bulletin '' '''21''': 442–50.</ref> Human activities can also be detrimental, and have threatened numerous bird species with extinction.
-Birds can act as vectors for spreading diseases such as [[psittacosis]], [[salmonellosis]], [[campylobacteriosis]], mycobacteriosis (avian [[tuberculosis]]), [[avian influenza]] (bird flu), [[giardiasis]], and [[cryptosporidiosis]] over long distances. Some of these are [[zoonosis|zoonotic diseases]] that can also be transmitted to humans.<ref>Reed KD, Meece JK, Henkel JS, Shukla SK (2003). [http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1069015 "Birds, Migration and Emerging Zoonoses: West Nile Virus, Lyme Disease, Influenza A and Enteropathogens".] Clin Med Res. '''1''' (1):5–12. PMID 15931279</ref>
-===Economic importance===
-Domesticated birds raised for meat and eggs, called [[poultry]], are the largest source of animal protein eaten by humans; in 2003, {{Nowrap|76 million}} tons of poultry and {{Nowrap|61 million}} tons of eggs were produced worldwide.<ref>{{cite web|url= http://www.earth-policy.org/Books/Out/Ote3_3.htm|title= Shifting protein sources: Chapter 3: Moving Up the Food Chain Efficiently.|publisher=
-Earth Policy Institute|accessdate= 18 December 2007}}</ref> [[Chicken]]s account for much of human poultry consumption, though turkeys, ducks, and geese are also relatively common. Many species of birds are also hunted for meat. Bird hunting is primarily a recreational activity except in extremely undeveloped areas. The most important birds hunted in North and South America are waterfowl; other widely hunted birds include [[pheasant]]s, [[turkey (bird)|wild turkeys]], [[quail]], [[dove]]s, [[partridge]], [[grouse]], [[snipe]], and [[woodcock]].<ref>Simeone A, Navarro X (2002). [http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2002000200012&lng=es&nrm=iso&tlng=en "Human exploitation of seabirds in coastal southern Chile during the mid-Holocene".] ''Rev. chil. hist. nat'' '''75''' (2): 423–31</ref> [[Muttonbirding]] is also popular in Australia and New Zealand.<ref>Hamilton S (2000). "How precise and accurate are data obtained using. an infra-red scope on burrow-nesting sooty shearwaters ''Puffinus griseus''?" ''Marine Ornithology'' '''28''' (1): 1–6 [http://www.marineornithology.org/PDF/28_1/28_1_1.pdf PDF]</ref> Though some hunting, such as that of muttonbirds, may be sustainable, hunting has led to the extinction or endangerment of dozens of species.<ref>Keane A, Brooke MD, Mcgowan PJK (2005). "Correlates of extinction risk and hunting pressure in gamebirds (Galliformes)". ''Biological Conservation'' '''126''' (2): 216–33. {{DOI|10.1016/j.biocon.2005.05.011}}</ref>
-[[File:FishingCormorants.jpg|thumb|upright|alt= Illustration of fisherman on raft with pole for punting and numerous black birds on raft|The use of cormorants by Asian fishermen is in steep decline but survives in some areas as a tourist attraction.]]
-Other commercially valuable products from birds include feathers (especially the [[Down feather|down]] of geese and ducks), which are used as insulation in clothing and bedding, and seabird feces ([[guano]]), which is a valuable source of phosphorus and nitrogen. The [[War of the Pacific]], sometimes called the Guano War, was fought in part over the control of guano deposits.<ref>{{cite web|url= http://www.zum.de/whkmla/military/19cen/guanowar.html|title= The Guano War of 1865–1866.|publisher= World History at KMLA|accessdate= 18 December 2007}}</ref>
-Birds have been domesticated by humans both as pets and for practical purposes. Colourful birds, such as [[Parrot (family)|parrots]] and [[myna]]s, are bred in [[aviculture|captivity]] or kept as pets, a practice that has led to the illegal trafficking of some [[endangered species]].<ref>Cooney R, Jepson P (2006). "The international wild bird trade: what's wrong with blanket bans?" ''Oryx'' '''40''' (1): 18–23. [http://journals.cambridge.org/production/action/cjoGetFulltext?fulltextid=409231 PDF]</ref> [[Falcon]]s and [[cormorant]]s have long been used for [[Falconry|hunting]] and fishing, respectively. [[Messenger pigeon]]s, used since at least 1&nbsp;AD, remained important as recently as [[World War&nbsp;II]]. Today, such activities are more common either as hobbies, for entertainment and tourism,<ref>Manzi M (2002). [http://findarticles.com/p/articles/mi_go1895/is_200210/ai_n8674873 "Cormorant fishing in Southwestern China: a Traditional Fishery under Siege. (Geographical Field Note)"]. ''Geographic Review'' '''92''' (4): 597–603.</ref> or for sports such as [[pigeon racing]].
-Amateur bird enthusiasts (called birdwatchers, twitchers or, more commonly, [[birding|birders]]) number in the millions.<ref>Pullis La Rouche, G. (2006). Birding in the United States: a demographic and economic analysis. ''Waterbirds around the world.'' Eds. G.C. Boere, C.A. Galbraith and D.A. Stroud. [[The Stationery Office]], Edinburgh, UK. pp. 841–46. [http://www.jncc.gov.uk/PDF/pub07_waterbirds_part6.2.5.pdf PDF]</ref> Many homeowners erect [[bird feeder]]s near their homes to attract various species. [[Bird feeding]] has grown into a multimillion dollar industry; for example, an estimated 75% of households in Britain provide food for birds at some point during the winter.<ref>Chamberlain DE, Vickery JA, Glue DE, Robinson RA, Conway GJ, Woodburn RJW, Cannon AR (2005). "Annual and seasonal trends in the use of garden feeders by birds in winter". ''[[Ibis (journal)|Ibis]]'' '''147''' (3): 563–75. [http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1474-919x.2005.00430.x PDF]</ref>
 ===Religion, folklore and culture===
@@ Line 347: / Line 210: @@
 Perceptions of various bird species often vary across cultures. [[Owl]]s are associated with bad luck, [[witchcraft]], and death in parts of Africa,<ref>Enriquez PL, Mikkola H (1997). "Comparative study of general public owl knowledge in Costa Rica, Central America and Malawi, Africa". pp. 160–66 In: J.R. Duncan, D.H. Johnson, T.H. Nicholls, (Eds). ''Biology and conservation of owls of the Northern Hemisphere. General Technical Report NC-190'', USDA Forest Service, St. Paul, Minnesota. 635 pp.</ref> but are regarded as wise across much of Europe.<ref>Lewis DP (2005). [http://www.owlpages.com/articles.php?section=Owl+Mythology&title=Myth+and+Culture Owls in Mythology and Culture.] The Owl Pages. Retrieved on 15 September 2007</ref> [[Hoopoe]]s were considered sacred in [[Ancient Egypt]] and symbols of virtue in [[Persia]], but were thought of as thieves across much of Europe and harbingers of war in [[Scandinavia]].<ref>Dupree N (1974). "An Interpretation of the Role of the Hoopoe in Afghan Folklore and Magic". ''Folklore'' '''85''' (3): 173–93.</ref>
-===Conservation===
-[[File:California-Condor3-Szmurlo edit.jpg|thumb|right|alt= Large black bird with featherless head and hooked bill|upright|The [[California Condor]] once numbered only 22 birds, but conservation measures have raised that to over 300 today.]]
-{{Main|Bird conservation}}
-{{See also|Late Quaternary prehistoric birds|List of extinct birds|Raptor conservation}}
-Though human activities have allowed the expansion of a few species, such as the [[Barn Swallow]] and [[European Starling]], they have caused population decreases or [[extinction]] in many other species. Over a hundred bird species have gone extinct in historical times,<ref>Fuller E (2000). ''Extinct Birds'' (2nd ed.). [[Oxford University Press]], Oxford, New York. ISBN 0-19-850837-9</ref> although the most dramatic human-caused avian extinctions, eradicating an estimated 750–1800 species, occurred during the human colonisation of [[Melanesia]]n, [[Polynesia]]n, and [[Micronesia]]n islands.<ref>Steadman D (2006). ''Extinction and Biogeography in Tropical Pacific Birds'', University of Chicago Press. ISBN 978-0-226-77142-7</ref> Many bird populations are declining worldwide, with 1,227 species listed as [[threatened species|threatened]] by [[Birdlife International]] and the [[IUCN]] in 2009.<ref>{{cite web |title=BirdLife International announces more Critically Endangered birds than ever before |publisher=[[Birdlife International]] |date=14 May 2009 |url=http://www.birdlife.org/news/pr/2009/05/red_list.html |accessdate=15 May 2009}}</ref><ref>{{cite web |url=http://news.bbc.co.uk/2/hi/science/nature/8045971.stm |first=Mark |last=Kinver |title=Birds at risk reach record high |publisher= BBC News Online |date=13 May 2009 |accessdate=15 May 2009}}</ref>
-The most commonly cited human threat to birds is [[Habitat destruction|habitat loss]].<ref>Norris K, Pain D (eds, 2002). ''Conserving Bird Biodiversity: General Principles and their Application'' Cambridge University Press. ISBN 978-0521789493</ref> Other threats include overhunting, accidental mortality due to [[bird strike|structural collisions]] or [[long-line fishing]] [[bycatch]],<ref>Brothers NP (1991). "Albatross mortality and associated bait loss in the Japanese longline fishery in the southern ocean". ''Biological Conservation'' '''55''': 255–68.</ref> pollution (including [[oil spill]]s and pesticide use),<ref>Wurster D, Wurster C, Strickland W (1965). "Bird Mortality Following DDT Spray for Dutch Elm Disease". ''Ecology'' '''46''' (4): 488–99. {{DOI|10.1126/science.148.3666.90}}</ref> competition and predation from nonnative [[invasive species]],<ref>Blackburn T, Cassey P, Duncan R, Evans K, Gaston K (2004). "Avian Extinction and Mammalian Introductions on Oceanic Islands". ''[[Science (journal)|Science]]'' '''305''': 1955–58. {{DOI|10.1126/science.1101617}}</ref> and climate change.
-Governments and [[conservation biology|conservation]] groups work to protect birds, either by passing laws that [[In-situ conservation|preserve]] and [[ecological restoration|restore]] bird habitat or by establishing [[Ex-situ conservation|captive populations]] for reintroductions. Such projects have produced some successes; one study estimated that conservation efforts saved 16 species of bird that would otherwise have gone extinct between 1994 and 2004, including the [[California Condor]] and [[Norfolk Island Green Parrot]].<ref>Butchart S, Stattersfield A, Collar N (2006). "How many bird extinctions have we prevented?" ''Oryx'' '''40''' (3): 266–79 [http://www.birdlife.org/news/news/2006/08/butchart_et_al_2006.pdf PDF]</ref>
-{{-}}
 ==Notes==<!-- CytogenetGenomeResRes96:97,117:103,117:120,117:165. -->
@@ Line 362: / Line 215: @@
 ==External links==
-{{portalpar|Birds}}
-{{sisterlinks|wikt=bird|b=Bird|q=Birds|s=Bird|commons=Aves|n=Bird|v=Bird|species=Aves}}
-{{Wikibooks|Dichotomous Key|Aves}}
 *[http://www.bsc-eoc.org/avibase/avibase.jsp?lang=EN&pg=home Avibase]&nbsp;– The World Bird Database
 *[http://www.birdlife.org/ Birdlife International]&nbsp;– Dedicated to bird conservation worldwide; has a database with about 250,000 records on endangered bird species.
@@ Line 381: / Line 231: @@
 {{Birds}}
 {{Chordata}}
-{{Archosauromorpha}}