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Referring to great power relations pre-1960, Joshua Baron highlights that starting from around the 16th century and the rise of several European great powers, military conflicts and confrontations was the defining characteristic of diplomacy and relations between such powers. "Between 1500 and 1953, there were 64 wars in which at least one great power was opposed to another, and they averaged little more than five years in length. In approximately a 450-year time frame, on average at least two great powers were fighting one another in each and every year." Even during the period of Pax Britannica (or "the British Peace") between 1815 and 1914, war and military confrontations among the great powers was still a frequent occurrence. In fact, Joshua Baron points out that, in terms of militarized conflicts or confrontations, the UK led the way in this period with nineteen such instances against; Russia (8), France (5), Germany/Prussia (5) and Italy (1).
Birds (Aves) are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. Birds live worldwide and range in size from the 5 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich. They rank as the class of tetrapods with the most living species, at approximately ten thousand, with more than half of these being passerines, sometimes known as perching birds or, less accurately, as songbirds.
The fossil record indicates that birds are the last surviving dinosaurs, having evolved from feathered ancestors within the theropod group of saurischian dinosaurs. True birds first appeared during the Cretaceous period, around 100 million years ago. DNA-based evidence finds that birds diversified dramatically around the time of the Cretaceous–Paleogene extinction event that killed off all other dinosaurs. Birds in South America survived this event and then migrated to other parts of the world via multiple land bridges while diversifying during periods of global cooling. Primitive bird-like dinosaurs that lie outside class Aves proper, in the broader group Avialae, have been found dating back to the mid-Jurassic period. Many of these early "stem-birds", such as Archaeopteryx, were not yet capable of fully powered flight, and many retained primitive characteristics like toothy jaws in place of beaks, and long bony tails.
Birds have wings which are more or less developed depending on the species; the only known groups without wings are the extinct moas and elephant birds. Wings, which evolved from forelimbs, give most birds the ability to fly, although further speciation has led to some flightless birds, including ratites, penguins, and diverse endemic island species of birds. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly the aforementioned flightless penguins, and also members of the duck family, have also evolved for swimming. Birds, specifically Darwin's finches, played an important part in the inception of Darwin's theory of evolution by natural selection.
Some birds, especially corvids and parrots, are among the most intelligent animals; several bird species make and use tools, and many social species pass on knowledge across generations, which is considered a form of culture. Many species annually migrate great distances. Birds are social, communicating with visual signals, calls, and bird songs, and participating in such social behaviours as 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 polygynous ("many females") or, rarely, polyandrous ("many males") breeding systems. Birds produce offspring by laying eggs which are fertilized through sexual reproduction. They are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching. Some birds, such as hens, lay eggs even when not fertilized, though unfertilized eggs do not produce offspring.
Many species of birds are economically important. Domesticated and undomesticated birds (poultry and game) are important sources of eggs, meat, and feathers. Songbirds, parrots, and other species are popular as pets. Guano (bird excrement) is harvested for use as a fertilizer. Birds prominently figure throughout human culture. About 120–130 species have become extinct due to human activity since the 17th century, and hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry.
Aves and a sister group, the clade Crocodilia, contain the only living representatives of the reptile clade Archosauria. During the late 1990s, Aves was most commonly defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica. However, an earlier definition proposed by Jacques Gauthier gained wide currency in the 21st century, and is used by many scientists including adherents of the Phylocode system. Gauthier defined Aves to include only the crown group of the set of modern birds. This was done by excluding most groups known only from fossils, and assigning them, instead, to the Avialae, in part to avoid the uncertainties about the placement of Archaeopteryx in relation to animals traditionally thought of as theropod dinosaurs.
Based on fossil and biological evidence, most scientists accept that birds are a specialized subgroup of theropod dinosaurs, and more specifically, they are members of Maniraptora, a group of theropods which includes dromaeosaurs and oviraptorids, among others. As scientists have discovered more theropods 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 many small theropod feathered dinosaurs, contribute to this ambiguity.
The consensus view in contemporary paleontology is that the flying theropods, or avialans, are the closest relatives of the deinonychosaurs, which include dromaeosaurids and troodontids. Together, these form a group called Paraves. Some basal members of this group, such as Microraptor, have features which may have enabled them to glide or fly. The most basal deinonychosaurs were very small. This evidence raises the possibility that the ancestor of all paravians may have been arboreal, have been able to glide, or both. Unlike Archaeopteryx and the non-avialan feathered dinosaurs, who primarily ate meat, recent studies suggest that the first avialans were omnivores.
The Late Jurassic Archaeopteryx is well known as one of the first transitional fossils to be found, and it provided support for the theory of evolution in the late 19th century. Archaeopteryx was the first fossil to display both clearly traditional reptilian characteristics: teeth, clawed fingers, and a long, lizard-like tail, as well as wings with flight feathers similar to those of modern birds. It is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor.
The earliest known avialan fossils come from the Tiaojishan Formation of China, which has been dated to the late Jurassic period (Oxfordian stage), about 160 million years ago. The avialan species from this time period include Anchiornis huxleyi, Xiaotingia zhengi, and Aurornis xui. The well-known early avialan, Archaeopteryx, dates from slightly later Jurassic rocks (about 155 million years old) from Germany. Many of these early avialans shared unusual anatomical features that may be ancestral to modern birds, but were later lost during bird evolution. These features include enlarged claws on the second toe which may have been held clear of the ground in life, and long feathers or "hind wings" covering the hind limbs and feet, which may have been used in aerial maneuvering.
Avialans diversified into a wide variety of forms during the Cretaceous Period. Many groups retained primitive characteristics, such as clawed wings and teeth, though the latter were lost independently in a number of avialan groups, including modern birds (Aves). While the earliest forms, such as Archaeopteryx and Jeholornis, retained the long bony tails of their ancestors, the tails of more advanced avialans were shortened with the advent of the pygostyle bone in the group Pygostylia. In the late Cretaceous, around 95 million years ago, the ancestor of all modern birds also evolved a better sense of smell.
The first large, diverse lineage of short-tailed avialans 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. While they were the dominant group of avialans during the Cretaceous period, enantiornithes became extinct along with many other dinosaur groups at the end of the Mesozoic era.
Many species of the second major avialan lineage to diversify, the Euornithes (meaning "true birds", because they include the ancestors of modern birds), were semi-aquatic and specialized in eating fish and other small aquatic organisms. Unlike the enantiornithes, which dominated land-based and arboreal habitats, most early euornithes lacked perching adaptations and seem to have included shorebird-like species, waders, and swimming and diving species. The later included the superficially gull-like Ichthyornis, the Hesperornithiformes, which became so well adapted to hunting fish in marine environments that they lost the ability to fly and became primarily aquatic. The early euornithes also saw the development of many traits associated with modern birds, like strongly keeled breastbones, toothless, beaked portions of their jaws (though most non-avian euornithes retained teeth in other parts of the jaws). Euornithes also included the first avialans to develop true pygostyle and a fully mobile fan of tail feathers, which may have replaced the "hind wing" as the primary mode of aerial maneuverability and braking in flight.
All modern birds lie within the crown group Aves (alternately Neornithes), which has two subdivisions: the Palaeognathae, which includes the flightless ratites (such as the ostriches) and the weak-flying tinamous, and the extremely diverse Neognathae, containing all other birds. These two subdivisions are often given the rank of superorder, although Livezey and Zusi assigned them "cohort" rank. Depending on the taxonomic viewpoint, the number of known living bird species varies anywhere from 9,800 to 10,050.
The earliest divergence within the Neognathes was that of the Galloanserae, the superorder containing the Anseriformes (ducks, geese, swans and screamers) and the Galliformes (the pheasants, grouse, and their allies, together with the mound builders and the guans and their allies). The earliest fossil remains of true birds come from the possible galliform Austinornis lentus, dated to about 85 million years ago, but the dates for the actual splits are much debated by scientists. The Aves are agreed to have evolved in the Cretaceous, and the split between the Galloanseri from other Neognathes occurred before the Cretaceous–Paleogene extinction event, but there are different opinions about whether the radiation of the remaining Neognathes occurred before or after the extinction of the other dinosaurs. This disagreement is in part caused by a divergence in the evidence; molecular dating suggests a Cretaceous radiation, while fossil evidence supports a Cenozoic radiation. Attempts to reconcile the molecular and fossil evidence have proved controversial, but recent results show that all the extant groups of birds originated from only a small handful of species that survived the Cretaceous–Paleogene extinction.
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, although it is frequently debated and constantly revised. Most evidence seems to suggest the assignment of orders is accurate, 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. The most recent effort is drawn above and is based on whole genome sequencing of 48 representative species.
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 440 kilometres (270 mi) inland in Antarctica. 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. 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 and some penguins have been recorded diving up to 300 metres (980 ft).
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. Others have been accidental, such as the establishment of wild monk parakeets in several North American cities after their escape from captivity. Some species, including cattle egret, yellow-headed caracara and galah, have spread naturally far beyond their original ranges as agricultural practices created suitable new habitat.
The skeleton consists of very lightweight bones. They have large air-filled cavities (called pneumatic cavities) which connect with the respiratory system. The skull bones in adults are fused and do not show cranial sutures. 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. The last few are fused with the pelvis to form the synsacrum. 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.
Like the reptiles, birds are primarily uricotelic, that is, their kidneys extract nitrogenous waste from their bloodstream and excrete it as uric acid instead of urea or ammonia through the ureters into the intestine. Birds do not have a urinary bladder or external urethral opening and (with exception of the ostrich) uric acid is excreted along with feces as a semisolid waste. However, birds such as hummingbirds can be facultatively ammonotelic, excreting most of the nitrogenous wastes as ammonia. They also excrete creatine, rather than creatinine like mammals. This material, as well as the output of the intestines, emerges from the bird's cloaca. The cloaca is a multi-purpose opening: waste is expelled through it, most birds mate by joining cloaca, and females lay eggs from it. In addition, many species of birds regurgitate pellets. Males within Palaeognathae (with the exception of the kiwis), the Anseriformes (with the exception of screamers), and in rudimentary forms in Galliformes (but fully developed in Cracidae) possess a penis, which is never present in Neoaves. The length is thought to be related to sperm competition. When not copulating, it is hidden within the proctodeum compartment within the cloaca, just inside the vent. 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. Most birds are highly adapted for rapid digestion to aid with flight. Some migratory birds have adapted to use protein from many parts of their bodies, including protein from the intestines, as additional energy during migration.
Birds have one of the most complex respiratory systems of all animal groups. 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. Sound production is achieved using the syrinx, a muscular chamber incorporating multiple tympanic membranes which diverges from the lower end of the trachea; the trachea being elongated in some species, increasing the volume of vocalizations and the perception of the bird's size.
The avian circulatory system is driven by a four-chambered, myogenic heart contained in a fibrous pericardial sac. This pericardial sac is filled with a serous fluid for lubrication. The heart itself is divided into a right and left half, each with an atrium and ventricle. The atrium and ventricles of each side are separated by atrioventricular valves which prevent back flow from one chamber to the next during contraction. Being myogenic, the heart's pace is maintained by pacemaker cells found in the sinoatrial node, located on the right atrium. The sinoatrial node uses calcium to cause a depolarizing signal transduction pathway from the atrium through right and left atrioventricular bundle which communicates contraction to the ventricles. The avian heart also consists of muscular arches that are made up of thick bundles of muscular layers. Much like a mammalian heart, the avian heart is composed of endocardial, myocardial and epicardial layers. The atrium walls tend to be thinner than the ventricle walls, due to the intense ventricular contraction used to pump oxygenated blood throughout the body. Avian hearts are generally larger than mammalian hearts when compared to body mass. This adaptation allows more blood to be pumped to meet the high metabolic need associated with flight.
Birds have a very efficient system for diffusing oxygen into the blood; birds have a ten times greater surface area to gas exchange volume than mammals. As a result, birds have more blood in their capillaries per unit of volume of lung than a mammal. The arteries are composed of thick elastic muscles to withstand the pressure of the ventricular constriction, and become more rigid as they move away from the heart. Blood moves through the arteries, which undergo vasoconstriction, and into arterioles which act as a transportation system to distribute primarily oxygen as well as nutrients to all tissues of the body. As the arterioles move away from the heart and into individual organs and tissues they are further divided to increase surface area and slow blood flow. Travelling through the arterioles blood moves into the capillaries where gas exchange can occur. Capillaries are organized into capillary beds in tissues, it is here that blood exchanges oxygen for carbon dioxide waste. In the capillary beds blood flow is slowed to allow maximum diffusion of oxygen into the tissues. Once the blood has become deoxygenated it travels through venules then veins and back to the heart. Veins, unlike arteries, are thin and rigid as they do not need to withstand extreme pressure. As blood travels through the venules to the veins a funneling occurs called vasodilation bringing blood back to the heart. Once the blood reaches the heart it moves first into the right atrium, then the right ventricle to be pumped through the lungs for further gas exchange of carbon dioxide waste for oxygen. Oxygenated blood then flows from the lungs through the left atrium to the left ventricle where it is pumped out to the body.
The nervous system is large relative to the bird's size. 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, New World vultures and tubenoses. The avian visual system is usually highly developed. Water birds have special flexible lenses, allowing accommodation for vision in air and water. 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. This allows them to perceive ultraviolet light, which is involved in courtship. Birds have specialized light-sensing cells deep in their brains that respond to light without input from eyes or other sensory neurons. These photo-receptive cells in the hypothalamus are involved in detecting the longer days of spring, and thus regulate breeding activities.
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. 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. 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. The nictitating membrane also covers the eye and acts as a contact lens in many aquatic birds. The bird retina has a fan shaped blood supply system called the pecten. Most birds cannot move their eyes, although there are exceptions, such as the great cormorant. 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. 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.
A dearth of field observations limit our knowledge, but intraspecific conflicts are known to sometimes result in injury or death. The screamers (Anhimidae), some jacanas (Jacana, Hydrophasianus), the spur-winged goose (Plectropterus), the torrent duck (Merganetta) and nine species of lapwing (Vanellus) use a sharp spur on the wing as a weapon. The steamer ducks (Tachyeres), geese and swans (Anserinae), the solitaire (Pezophaps), sheathbills (Chionis), some guans (Crax) and stone curlews (Burhinus) use a bony knob on the alular metacarpal to punch and hammer opponents. The jacanas Actophilornis and Irediparra have an expanded, blade-like radius. The extinct Xenicibis was unique in having an elongate forelimb and massive hand which likely functioned in combat or defence as a jointed club or flail. Swans, for instance, may strike with the bony spurs and bite when defending eggs or young.
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. 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, and sex.
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. 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. A small number of species, such as ducks and geese, lose all of their flight feathers at once, temporarily becoming flightless. As a general rule, the tail feathers are moulted and replaced starting with the innermost pair. Centripetal moults of tail feathers are however seen in the Phasianidae. 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. The general pattern seen in passerines is that the primaries are replaced outward, secondaries inward, and the tail from center outward. 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.
Feathers require maintenance and birds preen or groom them daily, spending an average of around 9% of their daily time on this. 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. 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.
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. 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. Flightlessness often arises in birds on isolated islands, probably due to limited resources and the absence of land predators. Though flightless, penguins use similar musculature and movements to "fly" through the water, as do auks, shearwaters and dippers.
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. Birds' feeding strategies vary by species. Many birds glean for insects, invertebrates, fruit, or seeds. Some hunt insects by suddenly attacking from a branch. Those species that seek pest insects are considered beneficial 'biological control agents' and their presence encouraged in biological pest control programs. 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. Kiwis and shorebirds with long bills probe for invertebrates; shorebirds' varied bill lengths and feeding methods result in the separation of ecological niches. Loons, diving ducks, penguins and auks pursue their prey underwater, using their wings or feet for propulsion, 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. Geese and dabbling ducks are primarily grazers.
Some species, including frigatebirds, gulls, and skuas, 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%. 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.
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. Some desert birds depend on water sources and sandgrouse are particularly well known for their daily congregations at waterholes. Nesting sandgrouse and many plovers carry water to their young by wetting their belly feathers. Some birds carry water for chicks at the nest in their crop or regurgitate it along with food. The pigeon family, flamingos and penguins have adaptations to produce a nutritive fluid called crop milk that they provide to their chicks.
Feathers being critical to the survival of a bird, require maintenance. Apart from physical wear and tear, feathers face the onslaught of fungi, ectoparasitic feather mites and birdlice. The physical condition of feathers are maintained by preening often with the application of secretions from the preen gland. Birds also bathe in water or dust themselves. While some birds dip into shallow water, more aerial species may make aerial dips into water and arboreal species often make use of dew or rain that collect on leaves. Birds of arid regions make use of loose soil to dust-bathe. A behaviour termed as anting in which the bird encourages ants to run through their plumage is also thought to help them reduce the ectoparasite load in feathers. Many species will spread out their wings and expose them to direct sunlight and this too is thought to help in reducing fungal and ectoparasitic activity that may lead to feather damage.
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 polar 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. Migration is highly demanding energetically, particularly as birds need to cross deserts and oceans without refuelling. Landbirds have a flight range of around 2,500 km (1,600 mi) and shorebirds can fly up to 4,000 km (2,500 mi), although the bar-tailed godwit is capable of non-stop flights of up to 10,200 km (6,300 mi). 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 64,000 km (39,800 mi). 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.
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. 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. 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. 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. 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.
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 5,150 km (3,200 mi). 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. Orientation with the stellar compass depends on the position of the constellations surrounding Polaris. These are backed up in some species by their ability to sense the Earth's geomagnetism through specialised photoreceptors.
Birds sometimes use plumage to assess and assert social dominance, 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. 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. The most elaborate displays occur during courtship, where "dances" are often formed from complex combinations of many possible component movements; males' breeding success may depend on the quality of such displays.
Calls are used for a variety of purposes, including mate attraction, evaluation of potential mates, bond formation, the claiming and maintenance of territories, the identification of other individuals (such as when parents look for chicks in colonies or when mates reunite at the start of breeding season), and the warning of other birds of potential predators, sometimes with specific information about the nature of the threat. Some birds also use mechanical sounds for auditory communication. The Coenocorypha snipes of New Zealand drive air through their feathers, woodpeckers drum territorially, and palm cockatoos use tools to drum.
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. 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 increase potential competition for resources. Costs of flocking include bullying of socially subordinate birds by more dominant birds and the reduction of feeding efficiency in certain cases.
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. 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. It has been suggested that there may be certain kinds of sleep which are possible even when in flight. 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. Communal roosting is common because it lowers the loss of body heat and decreases the risks associated with predators. Roosting sites are often chosen with regard to thermoregulation and safety.
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. Some hummingbirds go into a nightly state of torpor accompanied with a reduction of their metabolic rates. 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. 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.
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. Monogamy allows for both paternal care and biparental care, which is especially important for species in which females require males' assistance for successful brood-rearing. Among many socially monogamous species, extra-pair copulation (infidelity) is common. 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. Female birds have sperm storage mechanisms that allow sperm from males to remain viable long after copulation, a hundred days in some species. Sperm from multiple males may compete through this mechanism. 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. Males of species that engage in extra-pair copulations will closely guard their mates to ensure the parentage of the offspring that they raise.
Breeding usually involves some form of courtship display, typically performed by the male. 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, although in the polyandrous phalaropes, this is reversed: plainer males choose brightly coloured females. Courtship feeding, billing and allopreening are commonly performed between partners, generally after the birds have paired and mated.
All birds lay amniotic eggs with hard shells made mostly of calcium carbonate. 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.
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. 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, and feathers are often used for nest insulation. 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.
Incubation, which optimises temperature for chick development, usually begins after the last egg has been laid. 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 (2.9 oz) of body weight per day of incubation. The warmth for the incubation of the eggs of megapodes comes from the sun, decaying vegetation or volcanic sources. Incubation periods range from 10 days (in woodpeckers, cuckoos and passerine birds) to over 80 days (in albatrosses and kiwis).
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. 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. The chick guard stage describes the period of breeding during which one of the adult birds is permanently present at the nest after chicks have hatched. The main purpose of the guard stage is to aid offspring to thermoregulate and protect them from predation.
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. Such alloparenting is particularly common among the Corvida, which includes such birds as the true crows, Australian magpie and fairy-wrens, 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. 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.
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. 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. Chicks may also follow their parents during their first migration.
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. 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. One hundred bird species, including honeyguides, icterids, and ducks, are obligate parasites, though the most famous are the cuckoos. 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.
Birds have evolved a variety of mating behaviors, with the peacock tail being perhaps the most famous example of sexual selection and the Fisherian runaway. Commonly occurring sexual dimorphisms such as size and color differences are energetically costly attributes that signal competitive breeding situations. Many types of avian sexual selection have been identified; intersexual selection, also known as female choice; and intrasexual competition, where individuals of the more abundant sex compete with each other for the privilege to mate. Sexually selected traits often evolve to become more pronounced in competitive breeding situations until the trait begins to limit the individual’s fitness. Conflicts between an individual fitness and signaling adaptations ensure that sexually selected ornaments such as plumage coloration and courtship behavior are "honest" traits. Signals must be costly to ensure that only good-quality individuals can present these exaggerated sexual ornaments and behaviors.
Incestuous matings by the purple-crowned fairy wren Malurus coronatus result in severe fitness costs due to inbreeding depression (greater than 30% reduction in hatchability of eggs). Females paired with related males may undertake extra pair matings (see Promiscuity#Other animals for 90% frequency in avian species) that can reduce the negative effects of inbreeding. However, there are ecological and demographic constraints on extra pair matings. Nevertheless, 43% of broods produced by incestuously paired females contained extra pair young.
Cooperative breeding in birds typically occurs when offspring, usually males, delay dispersal from their natal group in order to remain with the family to help rear younger kin. Female offspring rarely stay at home, dispersing over distances that allow them to breed independently, or to join unrelated groups. In general, inbreeding is avoided because it leads to a reduction in progeny fitness (inbreeding depression) due largely to the homozygous expression of deleterious recessive alleles. Cross-fertilization between unrelated individuals ordinarily leads to the masking of deleterious recessive alleles in progeny.
Birds occupy a wide range of ecological positions. 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 preying on birds.
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. Today the plants of New Zealand retain the defensive adaptations evolved to protect them from the extinct moa. 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 and the surrounding seas.
Since birds are highly visible and common animals, humans have had a relationship with them since the dawn of man. Sometimes, these relationships are mutualistic, like the cooperative honey-gathering among honeyguides and African peoples such as the Borana. Other times, they may be commensal, as when species such as the house sparrow have benefited from human activities. Several bird species have become commercially significant agricultural pests, and some pose an aviation hazard. Human activities can also be detrimental, and have threatened numerous bird species with extinction (hunting, avian lead poisoning, pesticides, roadkill, and predation by pet cats and dogs are common sources of death for birds).
Domesticated birds raised for meat and eggs, called poultry, are the largest source of animal protein eaten by humans; in 2003, 76 million tons of poultry and 61 million tons of eggs were produced worldwide. Chickens account for much of human poultry consumption, though domesticated 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 pheasants, wild turkeys, quail, doves, partridge, grouse, snipe, and woodcock. Muttonbirding is also popular in Australia and New Zealand. Though some hunting, such as that of muttonbirds, may be sustainable, hunting has led to the extinction or endangerment of dozens of species.
Birds have been domesticated by humans both as pets and for practical purposes. Colourful birds, such as parrots and mynas, are bred in captivity or kept as pets, a practice that has led to the illegal trafficking of some endangered species. Falcons and cormorants have long been used for hunting and fishing, respectively. Messenger pigeons, used since at least 1 AD, remained important as recently as World War II. Today, such activities are more common either as hobbies, for entertainment and tourism, or for sports such as pigeon racing.
Birds play prominent and diverse roles in religion and mythology. 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 or as attendants, as in the case of Hugin and Munin, the two common ravens who whispered news into the ears of the Norse god Odin. In several civilizations of ancient Italy, particularly Etruscan and Roman religion, 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. They may also serve as religious symbols, as when Jonah (Hebrew: יוֹנָה, dove) embodied the fright, passivity, mourning, and beauty traditionally associated with doves. Birds have themselves been deified, as in the case of the common peacock, which is perceived as Mother Earth by the Dravidians of India. In religious images preserved from the Inca and Tiwanaku empires, birds are depicted in the process of transgressing boundaries between earthly and underground spiritual realms. Indigenous peoples of the central Andes maintain legends of birds passing to and from metaphysical worlds. The mythical chullumpi bird is said to mark the existence of a portal between such worlds, and to transform itself into a llama.
Birds have featured in culture and art since prehistoric times, when they were represented in early cave paintings. Some birds have been perceived as monsters, including the mythological Roc and the Māori's legendary Pouākai, a giant bird capable of snatching humans. Birds were later used as symbols of power, as in the magnificent Peacock Throne of the Mughal and Persian emperors. 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. 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. 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'. Other English metaphors derive from birds; vulture funds and vulture investors, for instance, take their name from the scavenging vulture.
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, although the most dramatic human-caused avian extinctions, eradicating an estimated 750–1800 species, occurred during the human colonisation of Melanesian, Polynesian, and Micronesian islands. Many bird populations are declining worldwide, with 1,227 species listed as threatened by BirdLife International and the IUCN in 2009.
The Qing dynasty (Chinese: 清朝; pinyin: Qīng Cháo; Wade–Giles: Ch'ing Ch'ao; IPA: [tɕʰíŋ tʂʰɑ̌ʊ̯]), officially the Great Qing (Chinese: 大清; pinyin: Dà Qīng), also called the Empire of the Great Qing, or the Manchu dynasty, was the last imperial dynasty of China, ruling from 1644 to 1912 with a brief, abortive restoration in 1917. It was preceded by the Ming dynasty and succeeded by the Republic of China. The Qing multi-cultural empire lasted almost three centuries and formed the territorial base for the modern Chinese state.
The dynasty was founded by the Jurchen Aisin Gioro clan in Manchuria. In the late sixteenth century, Nurhaci, originally a Ming vassal, began organizing Jurchen clans into "Banners", military-social units. Nurhaci formed these clans into a unified entity, the subjects of which became known collectively as the Manchu people. By 1636, his son Hong Taiji began driving Ming forces out of Liaodong and declared a new dynasty, the Qing. In 1644, peasant rebels led by Li Zicheng conquered the Ming capital Beijing. Rather than serve them, Ming general Wu Sangui made an alliance with the Manchus and opened the Shanhai Pass to the Banner Armies led by Prince Dorgon, who defeated the rebels and seized Beijing. The conquest of China proper was not completed until 1683 under the Kangxi Emperor (r. 1661–1722). The Ten Great Campaigns of the Qianlong Emperor from the 1750s to the 1790s extended Qing control into Central Asia. While the early rulers maintained their Manchu ways, and while their official title was Emperor they were known as khans to the Mongols and patronized Tibetan Buddhism, they governed using Confucian styles and institutions of bureaucratic government. They retained the imperial examinations to recruit Han Chinese to work under or in parallel with Manchus. They also adapted the ideals of the tributary system in international relations, and in places such as Taiwan, the Qing so-called internal foreign policy closely resembled colonial policy and control.
The reign of the Qianlong Emperor (1735–1796) saw the apogee and initial decline in prosperity and imperial control. The population rose to some 400 million, but taxes and government revenues were fixed at a low rate, virtually guaranteeing eventual fiscal crisis. Corruption set in, rebels tested government legitimacy, and ruling elites did not change their mindsets in the face of changes in the world system. Following the Opium War, European powers imposed unequal treaties, free trade, extraterritoriality and treaty ports under foreign control. The Taiping Rebellion (1850–64) and Dungan Revolt (1862–77) in Central Asia led to the deaths of some 20 million people. In spite of these disasters, in the Tongzhi Restoration of the 1860s, Han Chinese elites rallied to the defense of the Confucian order and the Qing rulers. The initial gains in the Self-Strengthening Movement were destroyed in the First Sino-Japanese War of 1895, in which the Qing lost its influence over Korea and the possession of Taiwan. New Armies were organized, but the ambitious Hundred Days' Reform of 1898 was turned back by Empress Dowager Cixi, a ruthless but capable leader. When, in response to the violently anti-foreign Yihetuan ("Boxers"), foreign powers invaded China, the Empress Dowager declared war on them, leading to defeat and the flight of the Imperial Court to Xi'an.
After agreeing to sign the Boxer Protocol the government then initiated unprecedented fiscal and administrative reforms, including elections, a new legal code, and abolition of the examination system. Sun Yat-sen and other revolutionaries competed with reformers such as Liang Qichao and monarchists such as Kang Youwei to transform the Qing empire into a modern nation. After the death of Empress Dowager Cixi and the Guangxu Emperor in 1908, the hardline Manchu court alienated reformers and local elites alike. Local uprisings starting on October 11, 1911 led to the Xinhai Revolution. Puyi, the last emperor, abdicated on February 12, 1912.
Nurhaci declared himself the "Bright Khan" of the Later Jin (lit. "gold") state in honor both of the 12–13th century Jurchen Jin dynasty and of his Aisin Gioro clan (Aisin being Manchu for the Chinese 金 (jīn, "gold")). His son Hong Taiji renamed the dynasty Great Qing in 1636. There are competing explanations on the meaning of Qīng (lit. "clear" or "pure"). The name may have been selected in reaction to the name of the Ming dynasty (明), which consists of the Chinese characters for "sun" (日) and "moon" (月), both associated with the fire element of the Chinese zodiacal system. The character Qīng (清) is composed of "water" (氵) and "azure" (青), both associated with the water element. This association would justify the Qing conquest as defeat of fire by water. The water imagery of the new name may also have had Buddhist overtones of perspicacity and enlightenment and connections with the Bodhisattva Manjusri. The Manchu name daicing, which sounds like a phonetic rendering of Dà Qīng or Dai Ching, may in fact have been derived from a Mongolian word that means "warrior". Daicing gurun may therefore have meant "warrior state", a pun that was only intelligible to Manchu and Mongol people. In the later part of the dynasty, however, even the Manchus themselves had forgotten this possible meaning.
After conquering "China proper", the Manchus identified their state as "China" (中國, Zhōngguó; "Middle Kingdom"), and referred to it as Dulimbai Gurun in Manchu (Dulimbai means "central" or "middle," gurun means "nation" or "state"). The emperors equated the lands of the Qing state (including present day Northeast China, Xinjiang, Mongolia, Tibet and other areas) as "China" in both the Chinese and Manchu languages, defining China as a multi-ethnic state, and rejecting the idea that "China" only meant Han areas. The Qing emperors proclaimed that both Han and non-Han peoples were part of "China." They used both "China" and "Qing" to refer to their state in official documents, international treaties (as the Qing was known internationally as "China" or the "Chinese Empire") and foreign affairs, and "Chinese language" (Dulimbai gurun i bithe) included Chinese, Manchu, and Mongol languages, and "Chinese people" (中國之人 Zhōngguó zhī rén; Manchu: Dulimbai gurun i niyalma) referred to all subjects of the empire. In the Chinese-language versions of its treaties and its maps of the world, the Qing government used "Qing" and "China" interchangeably.
The Qing dynasty was founded not by Han Chinese, who constitute the majority of the Chinese population, but by a sedentary farming people known as the Jurchen, a Tungusic people who lived around the region now comprising the Chinese provinces of Jilin and Heilongjiang. The Manchus are sometimes mistaken for a nomadic people, which they were not. What was to become the Manchu state was founded by Nurhaci, the chieftain of a minor Jurchen tribe – the Aisin Gioro – in Jianzhou in the early 17th century. Originally a vassal of the Ming emperors, Nurhachi embarked on an intertribal feud in 1582 that escalated into a campaign to unify the nearby tribes. By 1616, he had sufficiently consolidated Jianzhou so as to be able to proclaim himself Khan of the Great Jin in reference to the previous Jurchen dynasty.
Relocating his court from Jianzhou to Liaodong provided Nurhachi access to more resources; it also brought him in close contact with the Khorchin Mongol domains on the plains of Mongolia. Although by this time the once-united Mongol nation had long since fragmented into individual and hostile tribes, these tribes still presented a serious security threat to the Ming borders. Nurhachi's policy towards the Khorchins was to seek their friendship and cooperation against the Ming, securing his western border from a powerful potential enemy.
There were too few ethnic Manchus to conquer China, so they gained strength by defeating and absorbing Mongols, but more importantly, adding Han Chinese to the Eight Banners. The Manchus had to create an entire "Jiu Han jun" (Old Han Army) due to the massive amount of Han Chinese soldiers which were absorbed into the Eight Banners by both capture and defection, Ming artillery was responsible for many victories against the Manchus, so the Manchus established an artillery corps made out of Han Chinese soldiers in 1641 and the swelling of Han Chinese numbers in the Eight Banners led in 1642 of all Eight Han Banners being created. It was defected Ming Han Chinese armies which conquered southern China for the Qing.
This was followed by the creation of the first two Han Banners in 1637 (increasing to eight in 1642). Together these military reforms enabled Hong Taiji to resoundingly defeat Ming forces in a series of battles from 1640 to 1642 for the territories of Songshan and Jinzhou. This final victory resulted in the surrender of many of the Ming dynasty's most battle-hardened troops, the death of Yuan Chonghuan at the hands of the Chongzhen Emperor (who thought Yuan had betrayed him), and the complete and permanent withdrawal of the remaining Ming forces north of the Great Wall.
Hong Taiji's bureaucracy was staffed with many Han Chinese, including many newly surrendered Ming officials. The Manchus' continued dominance was ensured by an ethnic quota for top bureaucratic appointments. Hong Taiji's reign also saw a fundamental change of policy towards his Han Chinese subjects. Nurhaci had treated Han in Liaodong differently according to how much grain they had, those with less than 5 to 7 sin were treated like chattel while those with more than that amount were rewarded with property. Due to a revolt by Han in Liaodong in 1623, Nurhachi, who previously gave concessions to conquered Han subjects in Liaodong, turned against them and ordered that they no longer be trusted; He enacted discriminatory policies and killings against them, while ordering that Han who assimilated to the Jurchen (in Jilin) before 1619 be treated equally as Jurchens were and not like the conquered Han in Liaodong. Hong Taiji instead incorporated them into the Jurchen "nation" as full (if not first-class) citizens, obligated to provide military service. By 1648, less than one-sixth of the bannermen were of Manchu ancestry. This change of policy not only increased Hong Taiji's manpower and reduced his military dependence on banners not under his personal control, it also greatly encouraged other Han Chinese subjects of the Ming dynasty to surrender and accept Jurchen rule when they were defeated militarily. Through these and other measures Hong Taiji was able to centralize power unto the office of the Khan, which in the long run prevented the Jurchen federation from fragmenting after his death.
Hong Taiji died suddenly in September 1643 without a designated heir. As the Jurchens had traditionally "elected" their leader through a council of nobles, the Qing state did not have in place a clear succession system until the reign of the Kangxi Emperor. The leading contenders for power at this time were Hong Taiji's oldest son Hooge and Hong Taiji' half brother Dorgon. A compromise candidate in the person of Hong Taiji's five-year-old son, Fulin, was installed as the Shunzhi Emperor, with Dorgon as regent and de facto leader of the Manchu nation.
Ming government officials fought against each other, against fiscal collapse, and against a series of peasant rebellions. They were unable to capitalise on the Manchu succession dispute and installation of a minor as emperor. In April 1644, the capital at Beijing was sacked by a coalition of rebel forces led by Li Zicheng, a former minor Ming official, who established a short-lived Shun dynasty. The last Ming ruler, the Chongzhen Emperor, committed suicide when the city fell, marking the official end of the dynasty.
Li Zicheng then led a coalition of rebel forces numbering 200,000[a] to confront Wu Sangui, the general commanding the Ming garrison at Shanhai Pass. Shanhai Pass is a pivotal pass of the Great Wall, located fifty miles northeast of Beijing, and for years its defenses kept the Manchus from directly raiding the Ming capital. Wu Sangui, caught between a rebel army twice his size and a foreign enemy he had fought for years, decided to cast his lot with the Manchus, with whom he was familiar. Wu Sangui may have been influenced by Li Zicheng's mistreatment of his family and other wealthy and cultured officials; it was said that Li also took Wu's concubine Chen Yuanyuan for himself. Wu and Dorgon allied in the name of avenging the death of the Chongzhen Emperor. Together, the two former enemies met and defeated Li Zicheng's rebel forces in battle on May 27, 1644.
The newly allied armies captured Beijing on June 6. The Shunzhi Emperor was invested as the "Son of Heaven" on October 30. The Manchus, who had positioned themselves as political heir to the Ming emperor by defeating the rebel Li Zicheng, completed the symbolic transition by holding a formal funeral for the Chongzhen Emperor. However the process of conquering the rest of China took another seventeen years of battling Ming loyalists, pretenders and rebels. The last Ming pretender, Prince Gui, sought refuge with the King of Burma, but was turned over to a Qing expeditionary army commanded by Wu Sangui, who had him brought back to Yunnan province and executed in early 1662.
Han Chinese Banners were made up of Han Chinese who defected to the Qing up to 1644 and joined the Eight Banners, giving them social and legal privileges in addition to being acculturated to Manchu culture. So many Han defected to the Qing and swelled the ranks of the Eight Banners that ethnic Manchus became a minority, making up only 16% in 1648, with Han Bannermen dominating at 75% and Mongol Bannermen making up the rest. This multi-ethnic force in which Manchus were only a minority conquered China for the Qing.
The Qing showed that the Manchus valued military skills in propaganda targeted towards the Ming military to get them to defect to the Qing, since the Ming civilian political system discriminated against the military. The three Liaodong Han Bannermen officers who played a massive role in the conquest of southern China from the Ming were Shang Kexi, Geng Zhongming, and Kong Youde and they governed southern China autonomously as viceroys for the Qing after their conquests. Normally the Manchu Bannermen acted only as reserve forces or in the rear and were used predominantly for quick strikes with maximum impact, so as to minimize ethnic Manchu losses; instead, the Qing used defected Han Chinese troops to fight as the vanguard during the entire conquest of China.
First, the Manchus had entered "China proper" because Dorgon responded decisively to Wu Sangui's appeal. Then, after capturing Beijing, instead of sacking the city as the rebels had done, Dorgon insisted, over the protests of other Manchu princes, on making it the dynastic capital and reappointing most Ming officials. Choosing Beijing as the capital had not been a straightforward decision, since no major Chinese dynasty had directly taken over its immediate predecessor's capital. Keeping the Ming capital and bureaucracy intact helped quickly stabilize the regime and sped up the conquest of the rest of the country. However, not all of Dorgon's policies were equally popular nor easily implemented.
Dorgon's controversial July 1645 edict (the "haircutting order") forced adult Han Chinese men to shave the front of their heads and comb the remaining hair into the queue hairstyle which was worn by Manchu men, on pain of death. The popular description of the order was: "To keep the hair, you lose the head; To keep your head, you cut the hair." To the Manchus, this policy was a test of loyalty and an aid in distinguishing friend from foe. For the Han Chinese, however, it was a humiliating reminder of Qing authority that challenged traditional Confucian values. The Classic of Filial Piety (Xiaojing) held that "a person's body and hair, being gifts from one's parents, are not to be damaged." Under the Ming dynasty, adult men did not cut their hair but instead wore it in the form of a top-knot. The order triggered strong resistance to Qing rule in Jiangnan and massive killing of ethnic Han Chinese. It was Han Chinese defectors who carried out massacres against people refusing to wear the queue.. Li Chengdong, a Han Chinese general who had served the Ming but surrendered to the Qing, ordered his Han troops to carry out three separate massacres in the city of Jiading within a month, resulting in tens of thousands of deaths. At the end of the third massacre, there was hardly any living person left in this city. Jiangyin also held out against about 10,000 Han Chinese Qing troops for 83 days. When the city wall was finally breached on 9 October 1645, the Han Chinese Qing army led by the Han Chinese Ming defector Liu Liangzuo (劉良佐), who had been ordered to "fill the city with corpses before you sheathe your swords," massacred the entire population, killing between 74,000 and 100,000 people. The queue was the only aspect of Manchu culture which the Qing forced on the common Han population. The Qing required people serving as officials to wear Manchu clothing, but allowed non-official Han civilians to continue wearing Hanfu (Han clothing).
Although his support had been essential to Shunzhi's ascent, Dorgon had through the years centralised so much power in his hands as to become a direct threat to the throne. So much so that upon his death he was extraordinarily bestowed the posthumous title of Emperor Yi (Chinese: 義皇帝), the only instance in Qing history in which a Manchu "prince of the blood" (Chinese: 親王) was so honored. Two months into Shunzhi's personal rule, Dorgon was not only stripped of his titles, but his corpse was disinterred and mutilated.[b] to atone for multiple "crimes", one of which was persecuting to death Shunzhi’s agnate eldest brother, Hooge. More importantly, Dorgon's symbolic fall from grace also signaled a political purge of his family and associates at court, thus reverting power back to the person of the emperor. After a promising start, Shunzhi's reign was cut short by his early death in 1661 at the age of twenty-four from smallpox. He was succeeded by his third son Xuanye, who reigned as the Kangxi Emperor.
The Manchus sent Han Bannermen to fight against Koxinga's Ming loyalists in Fujian. The Qing carried out a massive depopulation policy and seaban forcing people to evacuated the coast in order to deprive Koxinga's Ming loyalists of resources, this has led to a myth that it was because Manchus were "afraid of water". In Fujian, it was Han Bannermen who were the ones carrying out the fighting and killing for the Qing and this disproved the entirely irrelevant claim that alleged fear of the water on part of the Manchus had to do with the coastal evacuation and seaban. Even though a poem refers to the soldiers carrying out massacres in Fujian as "barbarian", both Han Green Standard Army and Han Bannermen were involved in the fighting for the Qing side and carried out the worst slaughter. 400,000 Green Standard Army soldiers were used against the Three Feudatories besides 200,000 Bannermen.
The sixty-one year reign of the Kangxi Emperor was the longest of any Chinese emperor. Kangxi's reign is also celebrated as the beginning of an era known as the "High Qing", during which the dynasty reached the zenith of its social, economic and military power. Kangxi's long reign started when he was eight years old upon the untimely demise of his father. To prevent a repeat of Dorgon's dictatorial monopolizing of power during the regency, the Shunzhi Emperor, on his deathbed, hastily appointed four senior cabinet ministers to govern on behalf of his young son. The four ministers — Sonin, Ebilun, Suksaha, and Oboi — were chosen for their long service, but also to counteract each other's influences. Most important, the four were not closely related to the imperial family and laid no claim to the throne. However, as time passed, through chance and machination, Oboi, the most junior of the four, achieved such political dominance as to be a potential threat. Even though Oboi's loyalty was never an issue, his personal arrogance and political conservatism led him into an escalating conflict with the young emperor. In 1669 Kangxi, through trickery, disarmed and imprisoned Oboi — a significant victory for a fifteen-year-old emperor over a wily politician and experienced commander.
The early Manchu rulers also established two foundations of legitimacy which help to explain the stability of their dynasty. The first was the bureaucratic institutions and the neo-Confucian culture which they adopted from earlier dynasties. Manchu rulers and Han Chinese scholar-official elites gradually came to terms with each other. The examination system offered a path for ethnic Han to become officials. Imperial patronage of Kangxi Dictionary demonstrated respect for Confucian learning, while the Sacred Edict of 1670 effectively extolled Confucian family values. The second major source of stability was the Central Asian aspect of their Manchu identity which allowed them to appeal to Mongol, Tibetan and Uighur constituents. The Qing used the title of Emperor (Huangdi) in Chinese while among Mongols the Qing monarch was referred to as Bogda khan (wise Khan), and referred to as Gong Ma in Tibet. Qianlong propagated the image of himself as Buddhist sage rulers, patrons of Tibetan Buddhism. In the Manchu language, the Qing monarch was alternately referred to as either Huwangdi (Emperor) or Khan with no special distinction between the two usages. The Kangxi Emperor also welcomed to his court Jesuit missionaries, who had first come to China under the Ming. Missionaries including Tomás Pereira, Martino Martini, Johann Adam Schall von Bell, Ferdinand Verbiest and Antoine Thomas held significant positions as military weapons experts, mathematicians, cartographers, astronomers and advisers to the emperor. The relationship of trust was however lost in the later Chinese Rites controversy.
Yet controlling the "Mandate of Heaven" was a daunting task. The vastness of China's territory meant that there were only enough banner troops to garrison key cities forming the backbone of a defense network that relied heavily on surrendered Ming soldiers. In addition, three surrendered Ming generals were singled out for their contributions to the establishment of the Qing dynasty, ennobled as feudal princes (藩王), and given governorships over vast territories in Southern China. The chief of these was Wu Sangui, who was given the provinces of Yunnan and Guizhou, while generals Shang Kexi and Geng Jingzhong were given Guangdong and Fujian provinces respectively.
As the years went by, the three feudal lords and their extensive territories became increasingly autonomous. Finally, in 1673, Shang Kexi petitioned Kangxi for permission to retire to his hometown in Liaodong province and nominated his son as his successor. The young emperor granted his retirement, but denied the heredity of his fief. In reaction, the two other generals decided to petition for their own retirements to test Kangxi's resolve, thinking that he would not risk offending them. The move backfired as the young emperor called their bluff by accepting their requests and ordering that all three fiefdoms to be reverted to the crown.
Faced with the stripping of their powers, Wu Sangui, later joined by Geng Zhongming and by Shang Kexi's son Shang Zhixin, felt they had no choice but to revolt. The ensuing Revolt of the Three Feudatories lasted for eight years. Wu attempted, ultimately in vain, to fire the embers of south China Ming loyalty by restoring Ming customs, ordering that the resented queues be cut, and declaring himself emperor of a new dynasty. At the peak of the rebels' fortunes, they extended their control as far north as the Yangtze River, nearly establishing a divided China. Wu then hesitated to go further north, not being able to coordinate strategy with his allies, and Kangxi was able to unify his forces for a counterattack led by a new generation of Manchu generals. By 1681, the Qing government had established control over a ravaged southern China which took several decades to recover. Manchu Generals and Bannermen were initially put to shame by the better performance of the Han Chinese Green Standard Army, who fought better than them against the rebels and this was noted by Kangxi, leading him to task Generals Sun Sike, Wang Jinbao, and Zhao Liangdong to lead Green Standard Soldiers to crush the rebels. The Qing thought that Han Chinese were superior at battling other Han people and so used the Green Standard Army as the dominant and majority army in crushing the rebels instead of Bannermen. Similarly, in northwestern China against Wang Fuchen, the Qing used Han Chinese Green Standard Army soldiers and Han Chinese Generals such as Zhang Liangdong, Wang Jinbao, and Zhang Yong as the primary military forces. This choice was due to the rocky terrain, which favoured infantry troops over cavalry, to the desire to keep Bannermen in the reserves, and, again, to the belief that Han troops were better at fighting other Han people. These Han generals achieved victory over the rebels. Also due to the mountainous terrain, Sichuan and southern Shaanxi were also retaken by the Han Chinese Green Standard Army under Wang Jinbao and Zhao Liangdong in 1680, with Manchus only participating in dealing with logistics and provisions. 400,000 Green Standard Army soldiers and 150,000 Bannermen served on the Qing side during the war. 213 Han Chinese Banner companies, and 527 companies of Mongol and Manchu Banners were mobilized by the Qing during the revolt. 400,000 Green Standard Army soldiers were used against the Three Feudatories besides 200,000 Bannermen.
The Qing forces were crushed by Wu from 1673-1674. The Qing had the support of the majority of Han Chinese soldiers and Han elite against the Three Feudatories, since they refused to join Wu Sangui in the revolt, while the Eight Banners and Manchu officers fared poorly against Wu Sangui, so the Qing responded with using a massive army of more than 900,000 Han Chinese (non-Banner) instead of the Eight Banners, to fight and crush the Three Feudatories. Wu Sangui's forces were crushed by the Green Standard Army, made out of defected Ming soldiers.
To extend and consolidate the dynasty's control in Central Asia, the Kangxi Emperor personally led a series of military campaigns against the Dzungars in Outer Mongolia. The Kangxi Emperor was able to successfully expel Galdan's invading forces from these regions, which were then incorporated into the empire. Galdan was eventually killed in the Dzungar–Qing War. In 1683, Qing forces received the surrender of Taiwan from Zheng Keshuang, grandson of Koxinga, who had conquered Taiwan from the Dutch colonists as a base against the Qing. Zheng Keshuang was awarded the title "Duke Haicheng" (海澄公) and was inducted into the Han Chinese Plain Red Banner of the Eight Banners when he moved to Beijing. Several Ming princes had accompanied Koxinga to Taiwan in 1661-1662, including the Prince of Ningjing Zhu Shugui and Prince Zhu Honghuan (朱弘桓), son of Zhu Yihai, where they lived in the Kingdom of Tungning. The Qing sent the 17 Ming princes still living on Taiwan in 1683 back to mainland China where they spent the rest of their lives in exile since their lives were spared from execution. Winning Taiwan freed Kangxi's forces for series of battles over Albazin, the far eastern outpost of the Tsardom of Russia. Zheng's former soldiers on Taiwan like the rattan shield troops were also inducted into the Eight Banners and used by the Qing against Russian Cossacks at Albazin. The 1689 Treaty of Nerchinsk was China's first formal treaty with a European power and kept the border peaceful for the better part of two centuries. After Galdan's death, his followers, as adherents to Tibetan Buddhism, attempted to control the choice of the next Dalai Lama. Kangxi dispatched two armies to Lhasa, the capital of Tibet, and installed a Dalai Lama sympathetic to the Qing.
After the Kangxi Emperor's death in the winter of 1722, his fourth son, Prince Yong (雍親王), became the Yongzheng Emperor. In the later years of Kangxi's reign, Yongzheng and his brothers had fought, and there were rumours that he had usurped the throne(most of the rumours believe that Yongzheng's brother Yingzhen (Kangxi's 14th son) is the real successor of Kangxi Emperor, the reason why Yingzhen failed to sit on the throne is because Yongzheng and his confidant Keduo Long tampered the content of Kangxi's testament at the night when Kangxi passed away), a charge for which there is little evidence. In fact, his father had trusted him with delicate political issues and discussed state policy with him. When Yongzheng came to power at the age of 45, he felt a sense of urgency about the problems which had accumulated in his father's later years and did not need instruction in how to exercise power. In the words of one recent historian, he was "severe, suspicious, and jealous, but extremely capable and resourceful," and in the words of another, turned out to be an "early modern state-maker of the first order."
He moved rapidly. First, he promoted Confucian orthodoxy and reversed what he saw as his father's laxness by cracking down on unorthodox sects and by decapitating an anti-Manchu writer his father had pardoned. In 1723 he outlawed Christianity and expelled Christian missionaries, though some were allowed to remain in the capital. Next, he moved to control the government. He expanded his father's system of Palace Memorials which brought frank and detailed reports on local conditions directly to the throne without being intercepted by the bureaucracy, and created a small Grand Council of personal advisors which eventually grew into the emperor's de facto cabinet for the rest of the dynasty. He shrewdly filled key positions with Manchu and Han Chinese officials who depended on his patronage. When he began to realize that the financial crisis was even greater than he had thought, Yongzheng rejected his father's lenient approach to local landowning elites and mounted a campaign to enforce collection of the land tax. The increased revenues were to be used for "money to nourish honesty" among local officials and for local irrigation, schools, roads, and charity. Although these reforms were effective in the north, in the south and lower Yangzi valley, where Kangxi had wooed the elites, there were long established networks of officials and landowners. Yongzheng dispatched experienced Manchu commissioners to penetrate the thickets of falsified land registers and coded account books, but they were met with tricks, passivity, and even violence. The fiscal crisis persisted.
In 1725 Yongzheng bestowed the hereditary title of Marquis on a descendant of the Ming dynasty Imperial family, Zhu Zhiliang, who received a salary from the Qing government and whose duty was to perform rituals at the Ming tombs, and was also inducted the Chinese Plain White Banner in the Eight Banners. Later the Qianlong Emperor bestowed the title Marquis of Extended Grace posthumously on Zhu Zhuliang in 1750, and the title passed on through twelve generations of Ming descendants until the end of the Qing dynasty.
Yongzheng also inherited diplomatic and strategic problems. A team made up entirely of Manchus drew up the Treaty of Kyakhta (1727) to solidify the diplomatic understanding with Russia. In exchange for territory and trading rights, the Qing would have a free hand dealing with the situation in Mongolia. Yongzheng then turned to that situation, where the Zunghars threatened to re-emerge, and to the southwest, where local Miao chieftains resisted Qing expansion. These campaigns drained the treasury but established the emperor's control of the military and military finance.
Qianlong's reign saw the launch of several ambitious cultural projects, including the compilation of the Siku Quanshu, or Complete Repository of the Four Branches of Literature. With a total of over 3,400 books, 79,000 chapters, and 36,304 volumes, the Siku Quanshu is the largest collection of books in Chinese history. Nevertheless, Qianlong used Literary Inquisition to silence opposition. The accusation of individuals began with the emperor's own interpretation of the true meaning of the corresponding words. If the emperor decided these were derogatory or cynical towards the dynasty, persecution would begin. Literary inquisition began with isolated cases at the time of Shunzhi and Kangxi, but became a pattern under Qianlong's rule, during which there were 53 cases of literary persecution.
China also began suffering from mounting overpopulation during this period. Population growth was stagnant for the first half of the 17th century due to civil wars and epidemics, but prosperity and internal stability gradually reversed this trend. The introduction of new crops from the Americas such as the potato and peanut allowed an improved food supply as well, so that the total population of China during the 18th century ballooned from 100 million to 300 million people. Soon all available farmland was used up, forcing peasants to work ever-smaller and more intensely worked plots. The Qianlong Emperor once bemoaned the country's situation by remarking "The population continues to grow, but the land does not." The only remaining part of the empire that had arable farmland was Manchuria, where the provinces of Jilin and Heilongjiang had been walled off as a Manchu homeland. The emperor decreed for the first time that Han Chinese civilians were forbidden to settle. Mongols were forbidden by the Qing from crossing the borders of their banners, even into other Mongol Banners and from crossing into neidi (the Han Chinese 18 provinces) and were given serious punishments if they did in order to keep the Mongols divided against each other to benefit the Qing.
However Qing rule saw an massively increasing amount of Han Chinese both illegally and legally streaming into Manchuria and settling down to cultivate land as Manchu landlords desired Han Chinese peasants to rent on their land and grow grain, most Han Chinese migrants were not evicted as they went over the Great Wall and Willow Palisade, during the eighteenth century Han Chinese farmed 500,000 hectares of privately owned land in Manchuria and 203,583 hectares of lands which were part of coutrier stations, noble estates, and Banner lands, in garrisons and towns in Manchuria Han Chinese made up 80% of the population.
Han Chinese farmers were resettled from north China by the Qing to the area along the Liao River in order to restore the land to cultivation. Wasteland was reclaimed by Han Chinese squatters in addition to other Han who rented land from Manchu landlords. Despite officially prohibiting Han Chinese settlement on the Manchu and Mongol lands, by the 18th century the Qing decided to settle Han refugees from northern China who were suffering from famine, floods, and drought into Manchuria and Inner Mongolia so that Han Chinese farmed 500,000 hectares in Manchuria and tens of thousands of hectares in Inner Mongolia by the 1780s. Qianlong allowed Han Chinese peasants suffering from drought to move into Manchuria despite him issuing edicts in favor of banning them from 1740–1776. Chinese tenant farmers rented or even claimed title to land from the "imperial estates" and Manchu Bannerlands in the area. Besides moving into the Liao area in southern Manchuria, the path linking Jinzhou, Fengtian, Tieling, Changchun, Hulun, and Ningguta was settled by Han Chinese during the Qianlong Emperor's rule, and Han Chinese were the majority in urban areas of Manchuria by 1800. To increase the Imperial Treasury's revenue, the Qing sold formerly Manchu only lands along the Sungari to Han Chinese at the beginning of the Daoguang Emperor's reign, and Han Chinese filled up most of Manchuria's towns by the 1840s according to Abbe Huc.
However, the 18th century saw the European empires gradually expand across the world, as European states developed economies built on maritime trade. The dynasty was confronted with newly developing concepts of the international system and state to state relations. European trading posts expanded into territorial control in nearby India and on the islands that are now Indonesia. The Qing response, successful for a time, was in 1756 to establish the Canton System, which restricted maritime trade to that city and gave monopoly trading rights to private Chinese merchants. The British East India Company and the Dutch East India Company had long before been granted similar monopoly rights by their governments.