Diseases, Conditions, Syndromes

WHO urges flu vigilance after human H10N3 case

The World Health Organization (WHO) has urged countries to remain vigilant for influenza following the recent confirmation by Chinese health authorities of the first human case of infection with a rare strain of bird flu ...

Diseases, Conditions, Syndromes

First human case of H10N3 bird flu: What we know

China revealed the first human case of H10N3 bird flu on Tuesday, an announcement that has so far raised no alarm among world health authorities.

Diseases, Conditions, Syndromes

Nairobi's rapid green space losses could open door to more diseases

There's been widespread concern in Kenya over the shrinking of green spaces in Nairobi, the capital city. Most recently, there was uproar over the construction of a raised highway. This resulted in the felling of hundreds ...

Genetics

Forming sound memories: Autism gene plays key aspect in birdsong

Inactivating a gene in young songbirds that's closely linked with autism spectrum disorder (ASD) prevents the birds from forming memories necessary to accurately reproduce their fathers' songs, a new study led by UT Southwestern ...

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Bird

About two dozen - see section below

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.

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