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Yellow-legged Thrush
The yellow-legged thrush (''Turdus flavipes'') is a songbird of northern and eastern South America and the Caribbean. Taxonomy In recent times, it is increasingly often placed in the genus ''Turdus'' again, however some taxonomists place this species in the genus ''Platycichla'' based on morphology. The South American Classification Committee of the American Ornithologists' Union places it in the genus ''Turdus'', as does the International Ornithological Committee. Description This thrush is long and weighs . Both sexes have yellow legs and eye-ring. The male has a yellow bill and its plumage is usually black with a slate-grey back and lower underparts. However, the hue of the grey areas varies, and the male of one of the five subspecies, ''P. f. xanthoscelus'' of Tobago, is all-black, resembling the male Eurasian blackbird (''Turdus merula''). Females have a dull bill, warm brown upperparts and paler underparts. The juvenile male is brownish with black wings and tail, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Jean Pierre Vieillot
Louis Pierre Vieillot (10 May 1748, Yvetot – 24 August 1830, Sotteville-lès-Rouen) was a French ornithologist. Vieillot is the author of the first scientific descriptions and Linnaean names of a number of birds, including species he collected himself in the West Indies and North America and South American species discovered but not formally named by Félix de Azara and his translator Sonnini de Manoncourt. He was among the first ornithologists to study changes in plumage and one of the first to study live birds. At least 77 of the genera erected by Vieillot are still in use. Biography Vieillot was born in Yvetot. He represented his family's business interests in Saint-Domingue (Haiti) on Hispaniola, but fled to the United States during the Haitian rebellions that followed the French Revolution. On Buffon's advice, he collected material for the ''Histoire naturelle des oiseaux de l'Amérique Septentrionale,'' the first two volumes of which were published in France beginning i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disjunct Distribution
In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but considerably separated from each other geographically. The causes are varied and might demonstrate either the expansion or contraction of a species' range. Range fragmentation Also called range fragmentation, disjunct distributions may be caused by changes in the environment, such as mountain building and continental drift or rising sea levels; it may also be due to an organism expanding its range into new areas, by such means as rafting, or other animals transporting an organism to a new location (plant seeds consumed by birds and animals can be moved to new locations during bird or animal migrations, and those seeds can be deposited in new locations in fecal matter). Other conditions that can produce disjunct distributions include: flooding, or changes in wind, stream, and current flows, plus others such as anthropogenic introduction of alien introduced species either acciden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Migration
Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by the availability of food. It occurs mainly in the northern hemisphere, where birds are funneled onto specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea. Migration of species such as storks, turtle doves, and swallows was recorded as many as 3,000 years ago by Ancient Greek authors, including Homer and Aristotle, and in the Book of Job. More recently, Johannes Leche began recording dates of arrivals of spring migrants in Finland in 1749, and modern scientific studies have used techniques including bird ringing and satellite tracking to trace migrants. Threats to migratory birds have grown with habitat destruction, especially of stopover and wintering sites, as wel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subpopulation
In statistics, a population is a set of similar items or events which is of interest for some question or experiment. A statistical population can be a group of existing objects (e.g. the set of all stars within the Milky Way galaxy) or a hypothetical and potentially infinite group of objects conceived as a generalization from experience (e.g. the set of all possible hands in a game of poker). A common aim of statistical analysis is to produce information about some chosen population. In statistical inference, a subset of the population (a statistical ''sample'') is chosen to represent the population in a statistical analysis. Moreover, the statistical sample must be unbiased and accurately model the population (every unit of the population has an equal chance of selection). The ratio of the size of this statistical sample to the size of the population is called a ''sampling fraction''. It is then possible to estimate the '' population parameters'' using the appropriate sample ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, the fourth-largest country in the Americas, and the eighth-largest country in the world. It shares the bulk of the Southern Cone with Chile to the west, and is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. Argentina is a federal state subdivided into twenty-three provinces, and one autonomous city, which is the federal capital and largest city of the nation, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a federal system. Argentina claims sovereignty over the Falkland Islands, South Georgia and the South Sandwich Islands, and a part of Antarctica. The earliest recorded human prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraguay
Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. It has a population of seven million, nearly three million of whom live in the capital and largest city of Asunción, and its surrounding metro. Although one of only two landlocked countries in South America (Bolivia is the other), Paraguay has ports on the Paraguay and Paraná rivers that give exit to the Atlantic Ocean, through the Paraná-Paraguay Waterway. Spanish conquistadores arrived in 1524, and in 1537, they established the city of Asunción, the first capital of the Governorate of the Río de la Plata. During the 17th century, Paraguay was the center of Jesuit missions, where the native Guaraní people were converted to Christianity and introduced to European culture. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Roraima
Mount Roraima ( es, Monte Roraima; Tepuy Roraima; Cerro Roraima pt, Monte Roraima ) is the highest of the Pakaraima chain of tepuis (table-top mountain) or plateaux in South America. It is located at the junction of Venezuela, Brazil and Guyana. A characteristic large flat-topped mountain surrounded by cliffs 400 to 1,000 meters high. The highest point of Mount Roraima is located on the southern edge of the cliff at an altitude of 2,810 meters in Venezuela, and another protrusion at an altitude of 2,772 meters at the junction of the three countries in the north of the plateau is the highest point in Guyana. The name of Mount Roraima came from the native Pemon people. ''Roroi'' in the Pemon language means "blue-green", and ''ma'' means "great". Leaching caused by intense rainfall has shaped the peculiar topography of the summit, and the geographical isolation of Mount Roraima has made it home to much endemic flora and fauna. Western exploration of Mount Roraima did not begin until ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guyana
Guyana ( or ), officially the Cooperative Republic of Guyana, is a country on the northern mainland of South America. Guyana is an indigenous word which means "Land of Many Waters". The capital city is Georgetown. Guyana is bordered by the Atlantic Ocean to the north, Brazil to the south and southwest, Venezuela to the west, and Suriname to the east. With , Guyana is the third-smallest sovereign state by area in mainland South America after Uruguay and Suriname, and is the second-least populous sovereign state in South America after Suriname; it is also one of the least densely populated countries on Earth. It has a wide variety of natural habitats and very high biodiversity. The region known as "the Guianas" consists of the large shield landmass north of the Amazon River and east of the Orinoco River known as the "land of many waters". Nine indigenous tribes reside in Guyana: the Wai Wai, Macushi, Patamona, Lokono, Kalina, Wapishana, Pemon, Akawaio and Warao. Histo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pakaraima Mountains
The Pacaraima or Pakaraima Mountains ( pt, Serra de Pacaraima, es, Sierra de Pacaraima) are a mountain range primarily in southwestern Guyana, and into northern Brazil and eastern Venezuela. Geography The range extends from west to east for over . Its highest peak is Mount Roraima at above sea level, a tepui surrounded by cliffs high. It is geologically part of the Guayana Shield and biogeographically part of the Guayana Highlands.The mountains form the divide between the Orinoco Valley to the north and the Amazon Basin to the south. They also serve as a natural boundary in the east–west direction, where they extend to form a border marker between Brazil and southeastern Venezuela and between Brazil and west central Guyana. Geology The Pacaraimas are a sandstone plateau underlain by a horizonal precambrian marine strata that arose in post-cretaceous time. Erosion of the sandstone (the Roraima Supergroup) results in dramatic escarpments, the individual remnants of which ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margarita Island
Margarita Island (, ) is the largest island in the Venezuelan state of Nueva Esparta, situated off the northeastern coast of the country, in the Caribbean Sea. The capital city of Nueva Esparta, La Asunción, is located on the island. History Age of Exploration Christopher Columbus was the first European to arrive on Margarita Island in 1498. The local natives were the Guaiqueries people. The coast of the island was abundant in pearls, which represented almost a third of all New World tribute to the Spanish Crown. Margarita Island was fortified against the increasing threat of pirate attacks, and some fortifications remain today. It was the center of Spanish colonial Margarita Province, established in 1525. In 1561, the island was seized by Lope de Aguirre, a notoriously violent and rebellious conquistador. Around 1675, the island was captured again, this time by Red Legs Greaves, a pirate known for his humanity and morality. He captured a fleet of Spanish ships off por ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trinidad
Trinidad is the larger and more populous of the two major islands of Trinidad and Tobago. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is often referred to as the southernmost island in the West Indies. With an area of , it is also the List of Caribbean islands by area, fifth largest in the West Indies. Name The original name for the island in the Arawak language, Arawaks' language was which meant "Land of the Hummingbird". Christopher Columbus renamed it ('The Island of the Holy Trinity, Trinity'), fulfilling a vow he had made before setting out on his third voyage. This has since been shortened to ''Trinidad''. History Island Caribs, Caribs and Arawaks lived in Trinidad long before Christopher Columbus encountered the islands on his third voyage on 31 July 1498. The island remained Spanish until 1797, but it was largely settled by French colonists from the French Caribbean, especially Martinique.Besson, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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