英文的鸟类知识
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发布时间：2023-04-01 23:54
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热心网友
时间：2023-11-24 05:27
warm-blooded vertebrate of the class Aves, unique in having feathers, the one major characteristic that distinguishes them from all other animals. Birds have a four-chambered heart (shared with all mammals), forelimbs modified into wings (shared with bats), a calcareous-shelled egg, and keen vision, the major sense they rely on for information about the environment. Their sense of smell is not highly developed, and auditory range is limited. Most birds are diurnal in habit. There are approximately 8,700 living species, and more than 1,000 extinct species have been identified from fossil remains.
General features
Photograph:Ostriches (Struthio camelus); at left is the male
* Ostriches (Struthio camelus); at left is the male
The smallest living bird is generally acknowledged to be the bee hummingbird of Cuba, which is 6.3 centimetres (2.5 inches) long and weighs less than 3 grams (about 0.1 ounce). The largest living bird is the ostrich (see photograph), which may stand 2.5 metres (8 feet) tall and weigh 135 kilograms (300 pounds). Some extinct birds were even larger: the largest of the moas of New Zealand and the elephant birds of Madagascar may have reached over 3 metres (10 feet) in height. Among flying birds, the wandering albatross has the greatest wingspan, up to 3.5 metres (11.5 feet), and the trumpeter swan perhaps the greatest weight, 17 kilograms (38 pounds). A Pleistocene condorlike bird, Teratornis incredibilis, had an estimated wingspan of about 5 metres (16.5 feet) and was by far the largest known flying bird.
The ability to fly has permitted an almost unlimited radiation of birds, so that they are now found virtually everywhere on earth, from occasional stragglers over the polar ice caps to complex communities in tropical forests. In general the number of species found breeding in a given area is directly proportional to the size of the area and the diversity of habitats available. The total number of species is also related to such factors as the position of the area with respect to migration routes and wintering grounds of species that nest outside the area. In the United States, Texas and California have both the largest number of species recorded (545 and 461, respectively, including both resident and migrant species) and the largest number breeding (300 and 286). Seven hundred and seventy-five species, 650 of them breeding, have been recorded from North America north of Mexico. The figures for Europe exclusive of the erstwhile U.S.S.R. are 577 and 420, and the figures for the former Soviet states are 704 and 622. Costa Rica, with an area of only about 51,000 square kilometres (about 20,000 square miles) and a known avifauna of at least 758 species, probably has the most diversified group for its size of any country.
Bird and human relationships
Wild birds and their eggs have been at least incidental sources of food for humans since their origin and still are in most societies. The eggs of some colonial seabirds, such as gulls, terns, and murres, or guillemots, and the young of some shearwaters (muttonbirds) are even now harvested in large quantities. With the development of agrarian human cultures, several species of birds became domesticated. Of these, chickens, cks, geese, and pigeons, descended from the red jungle fowl (Gallus gallus), mallard ck (Anas platyrhynchos), greylag goose (Anser anser), and rock dove (Columba livia), respectively, were taken in early and have been selectively bred into many varieties. After the discovery of the New World, the turkey (Meleagris gallopavo), which had already been domesticated by the Indians, and the Muscovy ck (Cairina moschata) were brought to Europe and proced several varieties. Guinea fowl (Numida meleagris) from Africa were also widely exported and kept not only for food but because they are noisy when alarmed, thus warning of the approach of intruders. Besides being a food source, pigeons have long been bred and trained for carrying messages, and the ability of frigate birds to “home” to their nesting colonies has enabled inhabitants of the South Seas to send messages by these birds.
With the development of modern culture, hunting evolved from a foraging activity to a sport, in which the food value of the game became secondary. Large sums are now spent annually on hunting waterfowl, quail, grouse, pheasants, doves, and other game birds. Sets of rules and conventions have been set up for hunting, and in one elaborate form of hunting, falconry, there is not only a large body of specialized information on keeping and training falcons but also a complex terminology, much of it centuries old.
Feathers have been used for decoration since early times. Their use in the headdresses of American Indians and various peoples of New Guinea is well known. Feather robes were made by Polynesians and Eskimos; down quilts, mattresses, and pillows are part of traditional European folk culture. Large feathers have often been used in fans, thereby providing an example of an object put to opposite uses—for cooling as well as for conserving heat. Whereas most feathers used in decorating are now saved as by-procts of poultry raising or hunting, until early in the 20th century, egrets, grebes, and other birds were widely shot for their plumes alone. Ostrich farms have been established to proce plumes. Large quills were once widely used for writing, and feathers have long been used on arrows and fishing lures.
Many birds are kept as pets. Small finches and parrots are especially popular and easy to keep. Of these, the canary (Serinus canaria) and the budgerigar of Australia (Melopsittacus unlatus, sometimes called parakeet) are widely kept and have been bred for a variety of colour types. On large parks and estates, ornamental species like peafowl (Pavo) and various exotic waterfowl and pheasants are often kept. Zoological parks in many cities import birds from many lands and are a source of recreation for millions of people each year.
With the rise of agriculture, man's relationship with birds became more complex. In regions where grain and fruit are grown, depredations by birds may be a serious problem. In North America various species of blackbirds (family Icteridae) are serious pests in grainfields; while in Africa a grain-eating finch, the red-billed quelea (Quelea quelea), occurs, like locusts, in plague proportions so numerous that alighting flocks may break the branches of trees. The use of city buildings for roosts by large flocks of starlings and blackbirds is also a problem, as is the nesting of albatrosses on airplane runways on Pacific islands. As a result of these problems, conferences on the control of avian pests are held with increasing frequency.
Although birds are subject to a great range of diseases and parasites, few of these are known to be capable of infecting man. Notable exceptions are ornithosis (or psittacosis), caused by one or more viruses that are transmitted directly to man from pigeons, parrots, and a variety of other birds, a serious and sometimes fatal disease resembling virus pneumonia. Encephalitis, an inflammation of the brain, is also serious and is transmitted from birds to man and to his domestic animals by biting arthropods, including mosquitos. Wild birds may also act as reservoirs for diseases that adversely affect domesticated birds. Much work has been done recently on the ecology of viruses, with more and more of them being found in birds.
The study of birds has contributed much to both the theoretical and practical aspects of biology. Darwin's studies of the Galápagos finches and other birds ring the voyage of the “Beagle” were important in his formulation of the idea of the origin of species through natural selection. Study collections of birds in research museums still provide the bases for important studies of geographic variation, speciation, and zoogeography, because birds are one of the best known of animal groups. Early work on the domestic fowl added to the development of both genetics and embryology. The study of animal behaviour (ethology) has been based to a large extent on studies of birds by Konrad Lorenz, Nikolaas Tinbergen, and their successors. Birds also have been the primary group in the study of migration and orientation and the effect of hormones on behaviour and physiology.
Birds feature prominently in mythology and the literature of many countries. Some of their attributes, real or imagined, have led to their symbolic use in art as in language. The aesthetic and recreational pleasures of birdwatching are increasingly being recognized.
Man's impact on bird populations has become increasingly strong. Since 1680, approximately 80 species of birds have become extinct, and an even larger number are seriously endangered. While pollution and pesticides are important factors in the decline of certain large species, such as the peregrine falcon, osprey, and brown pelican, the destruction of natural areas and introction of exotic animals and diseases have probably been the most devastating. Concerted efforts are required to ensure the survival of rare species and to learn as much as possible about them.
热心网友
时间：2023-11-24 05:27
warm-blooded vertebrate of the class Aves, unique in having feathers, the one major characteristic that distinguishes them from all other animals. Birds have a four-chambered heart (shared with all mammals), forelimbs modified into wings (shared with bats), a calcareous-shelled egg, and keen vision, the major sense they rely on for information about the environment. Their sense of smell is not highly developed, and auditory range is limited. Most birds are diurnal in habit. There are approximately 8,700 living species, and more than 1,000 extinct species have been identified from fossil remains.
General features
Photograph:Ostriches (Struthio camelus); at left is the male
* Ostriches (Struthio camelus); at left is the male
The smallest living bird is generally acknowledged to be the bee hummingbird of Cuba, which is 6.3 centimetres (2.5 inches) long and weighs less than 3 grams (about 0.1 ounce). The largest living bird is the ostrich (see photograph), which may stand 2.5 metres (8 feet) tall and weigh 135 kilograms (300 pounds). Some extinct birds were even larger: the largest of the moas of New Zealand and the elephant birds of Madagascar may have reached over 3 metres (10 feet) in height. Among flying birds, the wandering albatross has the greatest wingspan, up to 3.5 metres (11.5 feet), and the trumpeter swan perhaps the greatest weight, 17 kilograms (38 pounds). A Pleistocene condorlike bird, Teratornis incredibilis, had an estimated wingspan of about 5 metres (16.5 feet) and was by far the largest known flying bird.
The ability to fly has permitted an almost unlimited radiation of birds, so that they are now found virtually everywhere on earth, from occasional stragglers over the polar ice caps to complex communities in tropical forests. In general the number of species found breeding in a given area is directly proportional to the size of the area and the diversity of habitats available. The total number of species is also related to such factors as the position of the area with respect to migration routes and wintering grounds of species that nest outside the area. In the United States, Texas and California have both the largest number of species recorded (545 and 461, respectively, including both resident and migrant species) and the largest number breeding (300 and 286). Seven hundred and seventy-five species, 650 of them breeding, have been recorded from North America north of Mexico. The figures for Europe exclusive of the erstwhile U.S.S.R. are 577 and 420, and the figures for the former Soviet states are 704 and 622. Costa Rica, with an area of only about 51,000 square kilometres (about 20,000 square miles) and a known avifauna of at least 758 species, probably has the most diversified group for its size of any country.
Bird and human relationships
Wild birds and their eggs have been at least incidental sources of food for humans since their origin and still are in most societies. The eggs of some colonial seabirds, such as gulls, terns, and murres, or guillemots, and the young of some shearwaters (muttonbirds) are even now harvested in large quantities. With the development of agrarian human cultures, several species of birds became domesticated. Of these, chickens, cks, geese, and pigeons, descended from the red jungle fowl (Gallus gallus), mallard ck (Anas platyrhynchos), greylag goose (Anser anser), and rock dove (Columba livia), respectively, were taken in early and have been selectively bred into many varieties. After the discovery of the New World, the turkey (Meleagris gallopavo), which had already been domesticated by the Indians, and the Muscovy ck (Cairina moschata) were brought to Europe and proced several varieties. Guinea fowl (Numida meleagris) from Africa were also widely exported and kept not only for food but because they are noisy when alarmed, thus warning of the approach of intruders. Besides being a food source, pigeons have long been bred and trained for carrying messages, and the ability of frigate birds to “home” to their nesting colonies has enabled inhabitants of the South Seas to send messages by these birds.
With the development of modern culture, hunting evolved from a foraging activity to a sport, in which the food value of the game became secondary. Large sums are now spent annually on hunting waterfowl, quail, grouse, pheasants, doves, and other game birds. Sets of rules and conventions have been set up for hunting, and in one elaborate form of hunting, falconry, there is not only a large body of specialized information on keeping and training falcons but also a complex terminology, much of it centuries old.
Feathers have been used for decoration since early times. Their use in the headdresses of American Indians and various peoples of New Guinea is well known. Feather robes were made by Polynesians and Eskimos; down quilts, mattresses, and pillows are part of traditional European folk culture. Large feathers have often been used in fans, thereby providing an example of an object put to opposite uses—for cooling as well as for conserving heat. Whereas most feathers used in decorating are now saved as by-procts of poultry raising or hunting, until early in the 20th century, egrets, grebes, and other birds were widely shot for their plumes alone. Ostrich farms have been established to proce plumes. Large quills were once widely used for writing, and feathers have long been used on arrows and fishing lures.
Many birds are kept as pets. Small finches and parrots are especially popular and easy to keep. Of these, the canary (Serinus canaria) and the budgerigar of Australia (Melopsittacus unlatus, sometimes called parakeet) are widely kept and have been bred for a variety of colour types. On large parks and estates, ornamental species like peafowl (Pavo) and various exotic waterfowl and pheasants are often kept. Zoological parks in many cities import birds from many lands and are a source of recreation for millions of people each year.
With the rise of agriculture, man's relationship with birds became more complex. In regions where grain and fruit are grown, depredations by birds may be a serious problem. In North America various species of blackbirds (family Icteridae) are serious pests in grainfields; while in Africa a grain-eating finch, the red-billed quelea (Quelea quelea), occurs, like locusts, in plague proportions so numerous that alighting flocks may break the branches of trees. The use of city buildings for roosts by large flocks of starlings and blackbirds is also a problem, as is the nesting of albatrosses on airplane runways on Pacific islands. As a result of these problems, conferences on the control of avian pests are held with increasing frequency.
Although birds are subject to a great range of diseases and parasites, few of these are known to be capable of infecting man. Notable exceptions are ornithosis (or psittacosis), caused by one or more viruses that are transmitted directly to man from pigeons, parrots, and a variety of other birds, a serious and sometimes fatal disease resembling virus pneumonia. Encephalitis, an inflammation of the brain, is also serious and is transmitted from birds to man and to his domestic animals by biting arthropods, including mosquitos. Wild birds may also act as reservoirs for diseases that adversely affect domesticated birds. Much work has been done recently on the ecology of viruses, with more and more of them being found in birds.
The study of birds has contributed much to both the theoretical and practical aspects of biology. Darwin's studies of the Galápagos finches and other birds ring the voyage of the “Beagle” were important in his formulation of the idea of the origin of species through natural selection. Study collections of birds in research museums still provide the bases for important studies of geographic variation, speciation, and zoogeography, because birds are one of the best known of animal groups. Early work on the domestic fowl added to the development of both genetics and embryology. The study of animal behaviour (ethology) has been based to a large extent on studies of birds by Konrad Lorenz, Nikolaas Tinbergen, and their successors. Birds also have been the primary group in the study of migration and orientation and the effect of hormones on behaviour and physiology.
Birds feature prominently in mythology and the literature of many countries. Some of their attributes, real or imagined, have led to their symbolic use in art as in language. The aesthetic and recreational pleasures of birdwatching are increasingly being recognized.
Man's impact on bird populations has become increasingly strong. Since 1680, approximately 80 species of birds have become extinct, and an even larger number are seriously endangered. While pollution and pesticides are important factors in the decline of certain large species, such as the peregrine falcon, osprey, and brown pelican, the destruction of natural areas and introction of exotic animals and diseases have probably been the most devastating. Concerted efforts are required to ensure the survival of rare species and to learn as much as possible about them.
