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bird,warm-blooded, egg-laying, vertebratevertebrate,
any animal having a backbone or spinal column. Verbrates can be traced back to the Silurian period. In the adults of nearly all forms the backbone consists of a series of vertebrae. All vertebrates belong to the subphylum Vertebrata of the phylum Chordata.
..... Click the link for more information. animal having its body covered with feathersfeathers,
outgrowths of the skin, constituting the plumage of birds. Feathers grow only along certain definite tracts (pterylae), which vary in different groups of birds.
..... Click the link for more information. and its forelimbs modified into wingswings,
flight organs of the bird, the bat, and the insect. Birds' wings are pectoral appendages that are basically the same in skeletal structure as the forelimbs of all higher vertebrates, including the human arm.
..... Click the link for more information. , which are used by most birds for flight. Birds compose the class Aves (see ChordataChordata
, phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal skeletal support at some stage of their development. Most chordates are vertebrates (animals with backbones), but the phylum also includes some small marine invertebrate animals.
..... Click the link for more information. ). There are an estimated 9,000 living species.
Birds are believed to be extant members of a group of dinosaursdinosaur
[Gr., = terrible lizard], extinct land reptile of the Mesozoic era. The dinosaurs, which were egg-laying animals, ranged in length from 2 1-2 ft (91 cm) to about 127 ft (39 m).
..... Click the link for more information. called maniraptors (other maniraptors include Velociraptor and Oviraptor). They share with dinosaurs such characteristics as a foot with three primary toes and one accessory toe held high in back. Early birdlike animals include Archaeopteryx, the ichthyornithiforms, skillful flyers with toothed beaks, Archaeornithura, and the rooster-sized, flightless Patagopteryx. The fossil remains of the ArchaeopteryxArchaeopteryx
[Gr.,=primitive wing], a 150 million-year-old fossil animal first discovered in 1860 in the late Jurassic limestone of Solnhofen, Bavaria, and described the following year.
..... Click the link for more information. , which date to the Jurassic period, show reptilian tails, jaws with teeth, and clawed wings, but feathers (found also in some dinosaurs) were well developed. Pterosaurspterosaur
[Gr., = winged lizard], extinct flying reptile (commonly called pterodactyl [Gr., = wing finger]) of the order Pterosauria, common in the late Triassic and Cretaceous periods, from approximately 228 to 65 million years ago.
..... Click the link for more information. , another group of flying reptiles, did not share the common characteristics of birds and dinosaurs and are not considered birds. Whether the capacity for flight arose in tree-living dinosaurs that glided from branch to branch (the "trees-down" hypothesis) or in fast-running terrestrial dinosaurs (the "ground-up" hypothesis) continues to be debated. Indeed, the inclusion of birds in the dinosaur family tree, although accepted by most paleontologists, is debated by some. Archaeornithura, which dates to the Cretaceous period, is one of the earliest known ancestors of modern birds and resembles a modern wading bird.
Birds are of enormous value to humanity because of their destruction of insect pests and weed seeds. Many are useful as scavengers. The game birds hunted for food and sport include grousegrouse,
common name for a game bird of the colder parts of the Northern Hemisphere. There are about 18 species. Grouse are henlike terrestrial birds, protectively plumaged in shades of red, brown, and gray.
..... Click the link for more information. , pheasantpheasant,
common name for some members of a family (Phasianidae) of henlike birds related to the grouse and including the Old World partridge, the peacock, various domestic and jungle fowls, and the true pheasants (genus Phasianus).
..... Click the link for more information. , quailquail,
common name for a variety of small game birds related to the partridge, pheasant, and more distantly to the grouse. There are three subfamilies in the quail family: the New World quails; the Old World quails and partridges; and the true pheasants and seafowls.
..... Click the link for more information. , duckduck,
common name for wild and domestic waterfowl of the family Anatidae, which also includes geese and swans. It is hunted and bred for its meat, eggs, and feathers. Strictly speaking, duck refers to the female and drake to the male.
..... Click the link for more information. , and ploverplover
, common name for some members of the large family Charadriidae, shore birds, small to medium in size, found in ice-free lands all over the world. Plovers are plumpish wading birds with pigeonlike bills and strong markings of black or brown above with white below.
..... Click the link for more information. . The chief domestic birds are the chicken (see poultrypoultry,
domesticated fowl kept primarily for meat and eggs; including birds of the order Galliformes, e.g., the chicken, turkey, guinea fowl, pheasant, quail, and peacock; and natatorial (swimming) birds, e.g., the duck and goose.
..... Click the link for more information. ), duck, goosegoose,
common name for large wild and domesticated swimming birds related to the duck and the swan. Strictly speaking, the term goose is applied to the female and gander to the male.
..... Click the link for more information. , turkeyturkey,
common name for a large game and poultry bird related to the grouse and the pheasant. Its name derives from its "turk-turk" call. Turkeys are indigenous to the New World; American fossils date back 40 million years to the Oligocene.
..... Click the link for more information. , and guinea fowlguinea fowl
, common name for any of the seven species of gallinaceous birds of the family Numididae, native to Africa and Madagascar. The helmeted guinea fowl, Numida meleagris,
..... Click the link for more information. . Parrotsparrot,
common name for members of the order Psittaciformes, comprising nearly 400 species of colorful birds, pantropical in distribution, including the parakeets. Parrots have large heads and short necks, strong feet with two toes in front and two in back (facilitating climbing
..... Click the link for more information. and many members of the finchfinch,
common name for members of the Fringillidae, the largest family of birds (including over half the known species), found in most parts of the world except Australia.
..... Click the link for more information. family are kept as pets.
Characteristic Features and Behaviors
Like mammals, they have a four-chambered heart, and there is a complete separation of oxygenated and deoxygenated blood. The body temperature is from 2° to 14° higher than that of mammals. Birds have a relatively large brain, keen sight, and acute hearing, but little sense of smell. Birds are highly adapted for flightflight,
sustained, self-powered motion through the air, as accomplished by an animal, aircraft, or rocket. Animal Flight
Adaptation for flight is highly developed in birds and insects. The bat is the only mammal that accomplishes true flight.
..... Click the link for more information. . Their structure combines lightness and strength. Body weight is reduced by the presence of a horny bill instead of heavy jaws and teeth and by the air sacs in the hollow bones as well as in other parts of the body. Compactness and firmness are achieved by the fusion of bones in the pelvic region and in other parts of the skeleton. The heavier parts of the body—the gizzard, intestines, flight muscles, and thigh muscles—are all strategically located for maintaining balance in flight. Feathers, despite their lightness, are highly protective against cold and wet. The flight feathers, especially, have great strength. Feathers are renewed in the process of moltingmolting,
periodical shedding and renewal of the outer skin, exoskeleton, fur, or feathers of an animal. In most animals the process is triggered by secretions of the thyroid and pituitary glands.
..... Click the link for more information. . Some birds, such as the ostrich, the penguin, and the kiwi, lack the power of flight and have a flat sternum, or breastbone, without the prominent keel to which the well-developed flight muscles of other birds are attached. The bills of birds are well adapted to their food habits. Specialized bills are found in the crossbill, hummingbird, spoonbill, pelican, and woodpecker.
In the majority of species there are differences between male and female in plumage coloring. In these birds the male (except in the phalarope) is usually the more brilliant or the more distinctly marked and is the aggressor in courtship. Unusual courtship displays are performed by several species, particularly by the ruffed grouse, the bird of paradise, the crane, the pheasant, and the peacock. Birdsongbirdsong.
Song, call notes, and certain mechanical sounds constitute the language of birds. Song is produced in the syrinx, whose firm walls are derived from the rings of the trachea, and is modified by the larynx and tongue.
..... Click the link for more information. reaches its highest development during the breeding season, and singing ability is usually either restricted to or superior in the male. Most birds build a nestnest,
structure for the reception and incubation of the eggs of birds, reptiles, insects, and some fish or for the parturition of mammals, and also for the care of the young during their period of helplessness.
..... Click the link for more information. in which to lay their eggs. Some birds, such as the oriole, weave an intricate structure, while others lay their eggs directly on the ground or among a few seemingly carelessly assembled twigs. Eggs vary in size, number, color, and shape. In spring and fall many birds migrate. Not all of the factors motivating this behavior are fully understood. These trips often involve flights of hundreds and even thousands of miles over mountains and oceans (see also migration of animalsmigration of animals,
movements of animals in large numbers from one place to another. In modern usage the term is usually restricted to regular, periodic movements of populations away from and back to their place of origin.
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Among the periodicals devoted to the study of bird life are the Auk, the Condor, and the Wilson Bulletin. Books on birds include the many guides by R. T. PetersonPeterson, Roger Tory,
1908–96, American ornithologist, writer, and illustrator, b. Jamestown, N.Y. He became famous with his best-selling pocket-sized Field Guide to the Birds
..... Click the link for more information. ; the life histories of North American birds in F. Gill and A. Poole, ed., The Birds of North America (1992–2003); R. M. De Schauensee, A Guide to the Birds of South America (1970); A. Rutgers and K. A. Norris, ed., Encyclopaedia of Aviculture (3 vol., 1970–77); U.S. Bureau of Sports Fisheries and Wildlife, Birds in Our Lives (1970); J. Van Tyne and A. J. Berger, Fundamentals of Ornithology (1971); S. Cramp, ed., Handbook of the Birds of Europe, the Middle East, and North Africa (5 vol., 1977–88); M. Walters, Birds of the World (1980); L. H. Brown et al., The Birds of Africa (7 vol., 1982–2004); J. Farrand, Jr., Eastern Birds (1988) and Western Birds (1988); B. King et al., The Collins Field Guide to the Birds of South-East Asia (1988); S. Chatterjee, The Rise of Birds (1997); D. Attenborough, The Life of Birds (1998); P. Shipman, Taking Wing (1998); D. A. Sibley, The Sibley Guide to Birds (2000); T. Birkhead, The Wisdom of Birds: An Illustrated History of Ornithology (2009) and Bird Sense: What It's Like to Be a Bird (2012). A study of endangered birds and their habitats is Bird Watch (2011) by M. Walters.