Portal:Birds/Selected article
From Wikipedia, the free encyclopedia
The Atlas of Australian Birds is a major ongoing project initiated and managed by Birds Australia (formerly RAOU) to map the distribution of Australian birds. Birds Australia is a not-for-profit bird research and conservation organisation.
There have been other bird atlasses produced for various countries and islands around the world, but the Australian project was the first to cover an entire continent. Volunteers collected data on Australian birds in order to establish a database and publish a book (1984) summarising the findings. A second period of fieldwork nearly 20 years later resulted in the publication of a second atlas in 2002.
Scotland's wildlife is typical of the north west of Europe although several of the larger mammals such as the Brown Bear, Wolf, Eurasian Lynx, Beaver, Reindeer, Elk and Walrus were hunted to extinction in historic times. A population of Wild Cats remains. There are important populations of seals and internationally significant nesting grounds for a variety of seabirds such as Northern Gannets. The Golden Eagle is something of a national icon, and White-tailed Eagles and Ospreys are recent re-colonisations. The Scottish Crossbill is Britain's only endemic bird. The flora of the country is varied incorporating both deciduous and coniferous woodlands, and moorland and tundra species. Significant remnants of the native Scots Pine forest, can be found in places The Fortingall Yew may be 5,000 years old and is probably the oldest living thing in Europe.
The family Procellariidae is a group of seabirds which comprises the fulmarine petrels, the gadfly petrels, the prions and the shearwaters. This family is part of the bird order Procellariiformes. The procellariids are the most numerous family of tubenoses, and the most diverse. They range in size from the giant petrels, which are almost as large as the albatrosses, to the prions, which are as small as the larger storm-petrels. They feed on fish, squid and crustacea, with many also taking fisheries discards and carrion. All species are accomplished long-distance foragers, and many undertake long trans-equatorial migrations. They are colonial breeders, exhibiting long-term mate fidelity and site philopatry. In all species, each pair lays a single egg per breeding season. Their incubation times and chick-rearing periods are exceptionally long compared to other birds.
Birds (class Aves) are bipedal, warm-blooded, egg-laying vertebrate animals. Birds evolved from theropod dinosaurs during the Jurassic period, and the earliest known bird is the Late Jurassic Archaeopteryx. Ranging in size from tiny hummingbirds to the huge Ostrich and Emu, there are between 9,000-10,000 known living bird species in the world, making them the most diverse class of terrestrial vertebrates.
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 light but strong skeleton. Most birds have forelimbs modified as wings and can fly, though the ratites and several others, particularly endemic island species, have also lost the ability to fly.
Many species of bird undertake long distance annual migrations, and many more perform shorter more irregular movements. Birds are social and communicate using visual signals and through calls and song, and participate in social behaviours including cooperative hunting, cooperative breeding, flocking and mobbing of predators. Birds are primarily socially monogamous, with engagement in extra-pair copulations being common in some species; other species have polygamous or polyandrous breeding systems. Eggs are usually laid in a nest and incubated and most birds have an extended period of parental care after hatching.
Birds are economically important to humans: many are important sources of food, acquired either through hunting or farming, they also provide other products. Some species, particularly songbirds and parrots, are popular as pets. Birds figure prominently in all aspects of human culture from religion to poetry and popular music. About 120–130 species have become extinct as a result of human activity since 1600, and hundreds more prior to this. Currently around 1,200 species of birds are threatened with extinction by human activities and efforts are underway to protect them.
Seabirds are birds that have adapted to life in the marine environment. Whilst seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations. The first seabirds evolved in the Cretaceous, and modern seabird families emerged in the Paleogene. Seabirds live longer, breed later and have fewer young than other birds do, but they invest a great deal of time in those young that they do have. Most species nest in colonies, which can vary in size from a few dozen birds to many millions. They are famous for undertaking long annual migrations, crossing the equator or circumnavigating the Earth in some cases. They feed both at the ocean's surface and below it, and even feed on each other. Seabirds can be highly pelagic, coastal, or in some cases spend a part of the year away from the sea entirely. Seabirds and humans have a long history together: they have provided food to hunters, guided fishermen to fishing stocks and led sailors to land. Many species are currently threatened by human activities, and conservation efforts are underway.
The Emu is the largest bird native to Australia and the only extant member of the genus Dromaius. It is also the second-largest flightless bird in the world, after its ratite relative, the Ostrich. The soft-feathered, brown birds reach up to 2 m in height and weigh up to 45 kg. The Emu is common over most of mainland Australia, although it avoids heavily-populated areas, dense forest and very arid areas. Emus can travel great distances at a fast, economical trot and, if necessary, can sprint at 50 km/hour for some distance at a time. They are opportunistically nomadic, and may travel long distances to find food; they feed on a variety of plants and insects. The Emu subspecies that inhabited Tasmania became extinct following the European settlement of Australia in 1788; the distribution of the mainland subspecies has also been affected by human activities. The Emu was once common on the east coast, but is now uncommon there; by contrast, the development of agriculture and the provision of water for stock in the interior of the continent has increased the range of the Emu in arid regions. Emus are farmed for their meat, oil and leather.
Albatrosses are large seabirds allied to the procellarids, storm-petrels and diving-petrels in the order Procellariiformes. They range widely in the Southern Ocean and the North Pacific. They are absent from the North Atlantic, although fossil remains show they once occurred there too. Albatrosses are amongst the largest of flying birds, and the great albatrosses have the largest wingspans of any extant birds. Albatrosses are highly efficient in the air, using dynamic soaring and slope soaring to cover great distances with little exertion. They feed on squid, fish and krill by either scavenging, surface seizing or diving. Albatrosses are colonial, nesting for the most part on remote oceanic islands, often with several species nesting together. Pair bonds between males and females form over several years, with the use of ritualised dances, and will last for the life of the pair. A breeding season can take over a year from laying to fledging, with a single egg laid in each breeding attempt.
