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Bird
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Birds (class Aves) are winged, bipedal, endothermic (warm-blooded), vertebrate animals that lay eggs. There are around 10,000 living species, making them the most numerous tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Birds range in size from the 5 cm (2 in) Bee Hummingbird to the 2.7 m (8 ft 10 in) Ostrich. The fossil record indicates that birds evolved from theropod dinosaurs during the Jurassic period, around 150–200 Ma (million years ago), and the earliest known bird is the Late Jurassic Archaeopteryx, c 155–150 Ma. Most paleontologists regard birds as the only clade of dinosaurs that survived the Cretaceous–Tertiary extinction event approximately 65.5 Ma.
Modern birds are characterised by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. All birds have forelimbs modified as wings and most can fly, with some exceptions including ratites, penguins, and a number of diverse endemic island species. Birds also have unique digestive and respiratory systems that are highly adapted for flight. Some birds, especially corvids and parrots, are among the most intelligent animal species; a number of bird species have been observed manufacturing and using tools, and many social species exhibit cultural transmission of knowledge across generations.
Many species undertake long distance annual migrations, and many more perform shorter irregular movements. Birds are social; they communicate using visual signals and through calls and songs, and participate in social behaviours including cooperative breeding and hunting, flocking, and mobbing of predators. The vast majority of bird species are socially monogamous, usually for one breeding season at a time, sometimes for years, but rarely for life. Other species have breeding systems that are polygynous ("many females") or, rarely, polyandrous ("many males"). Eggs are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching.
Many species are of economic importance, mostly as sources of food acquired through hunting or farming. Some species, particularly songbirds and parrots, are popular as pets. Other uses include the harvesting of guano (droppings) for use as a fertiliser. Birds figure prominently in all aspects of human culture from religion to poetry to popular music. About 120–130 species have become extinct as a result of human activity since the 17th century, and hundreds more before then. Currently about 1,200 species of birds are threatened with extinction by human activities, though efforts are underway to protect them.
For more information about Bird, read the full article at
Wikipedia.
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News tagged with birds
New tool in the fight against mosquito-borne disease: A microbial 'mosquito net'
3 hours ago |
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Earlier this year, researchers showed that they could cut the lives of disease-carrying mosquitoes in half by infecting them with a bacterium they took from fruit flies. Now, a new report in the December 24th issue of Cell, ...
Study sheds light on microscopic flower petal ridges
Dec 22, 2009 |
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(PhysOrg.com) -- Microscopic ridges contouring the surface of flower petals might play a role in flashing that come-hither look pollinating insects can't resist. Michigan State University scientists and colleagues ...
Earliest toothless bird found
Other Sciences / Archaeology & Fossils
Dec 10, 2009 |
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(PhysOrg.com) -- A new species of bird from the Cretaceous period in China has been identified. It had toothless upper and lower jaws, and provides significant information on the diversification in the evolution ...
Tropical birds waited for land crossing between North and South America: study
Dec 09, 2009 |
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Despite their ability to fly, tropical birds waited until the formation of the land bridge between North and South America to move northward, according to a University of British Columbia study published this ...
Female birds -- acting just like the guys -- become sexual show-offs in cooperative breeding species
Dec 09, 2009 |
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(PhysOrg.com) -- Female birds in species that breed in groups can find themselves under pressure to sexually show off and evolve the same kinds of embellishments - like fanciful tail feathers or chest-puffing ...
Researchers Identify the Most Promiscuous Birds in the World
Dec 09, 2009 |
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(PhysOrg.com) -- UConn ornithologist Chris Elphick and his colleagues carried out DNA tests to discover the paternity of Saltmarsh Sparrow nestlings.
Birds Call to Warn Friends and Enemies
Dec 03, 2009 |
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(PhysOrg.com) -- Birds' alarm calls serve both to alert other birds to danger and to warn off predators. And some birds can pull a ventriloquist's trick, singing from the side of their mouths, according to a UC Davis study.
By feeding the birds, you could change their evolutionary fate
Dec 03, 2009 |
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Feeding birds in winter is a most innocent human activity, but it can nonetheless have profound effects on the evolutionary future of a species, and those changes can be seen in the very near term. That's ...
Some birds listen, instead of look, for mates
Dec 02, 2009 |
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Looks can be deceiving, but certain bird species have figured out that a voice can tell them most of what they need to know to find the right mate.
Birds Play an Important Role in the Spread of Lyme Disease
Dec 23, 2009 |
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(PhysOrg.com) -- The range of Lyme disease is spreading in North America and it appears that birds play a significant role by transporting the Lyme disease bacterium over long distances, a new study by the Yale School of ...
Limestone leaf warbler: New bird species discovered
Dec 21, 2009 |
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(PhysOrg.com) -- A diminutive, colorful bird living in the rocky forests of Laos and Vietnam has been discovered by a team of scientists from the Wildlife Conservation Society, Lao PDR Department of Forestry, Swedish University ...
New molecule identified in DNA damage response
Dec 08, 2009 |
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(PhysOrg.com) -- Evolution places the highest premium on reproduction, natural selection’s only standard for biological success. In the case of replicating cells, life spares no expense to ensure that the ...
Brains versus brawn: Study finds there's more to the Noisy Miner than just being a backyard bully
Dec 08, 2009 |
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(PhysOrg.com) -- Some consider the Noisy Miner bird a badly-behaved backyard bully - an avian aggressor that moves into the neighbourhood and quickly takes over.
App in the hand finds birds in bushes as you roam
Dec 08, 2009 |
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(AP) -- When Jory Langner finds time for a field trip during an upcoming visit to Washington, he won't have to ask local birders where to find candidates to add to his life list of birds sighted.
In Taiwan, bird catchers turn bird watchers
Dec 04, 2009 |
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When Yeh You-chin was a boy half a century ago, he ate migratory birds with relish, but now he is at the forefront of efforts to preserve the feathered visitors to his south Taiwan home.
