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San Benedicto Rock Wren
The San Benedicto rock wren (''Salpinctes obsoletus exsul'') is a small extinct passerine which was endemic to San Benedicto Island in the Revillagigedo Islands off Mexico. It was a subspecies of the rock wren. Extinction San Benedicto is a volcano, like all the Revillagigedo group. Unlike, for example, Roca Partida, it was still active in recent times. On August 1, 1952, lava fountains started to break out of the Boquerón vent, located in a rift between the two older volcano cones. By around 8:45, ejecta were thrown up for several km in a severe vulcanian eruption of magnitude 3 on the Volcanic Explosivity Index scale; pyroclastic flows rolled over the island. Two weeks later, the entire island was covered in ash and pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicula ... up ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Ridgway
Robert Ridgway (July 2, 1850 – March 25, 1929) was an American ornithologist specializing in systematics. He was appointed in 1880 by Spencer Fullerton Baird, secretary of the Smithsonian Institution, to be the first full-time curator of birds at the United States National Museum, a title he held until his death. In 1883, he helped found the American Ornithologists' Union, where he served as officer and journal editor. Ridgway was an outstanding descriptive taxonomist, capping his life work with ''The Birds of North and Middle America'' (eight volumes, 1901–1919). In his lifetime, he was unmatched in the number of North American bird species that he species description, described for science. As technical illustrator, Ridgway used his own paintings and outline drawings to complement his writing. He also published two books that systematized color names for describing birds, ''A Nomenclature of Colors for Naturalists'' (1886) and ''Color Standards and Color Nomenclature'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroclastic Flow
A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of but is capable of reaching speeds up to . The gases and tephra can reach temperatures of about . Pyroclastic flows are the deadliest of all volcanic hazards and are produced as a result of certain explosive eruptions; they normally touch the ground and hurtle downhill or spread laterally under gravity. Their speed depends upon the density of the current, the volcanic output rate, and the gradient of the slope. Origin of term The word ''pyroclast'' is derived from the Greek (''pýr''), meaning "fire", and (''klastós''), meaning "broken in pieces". A name for pyroclastic flows that glow red in the dark is (French, "burning cloud"); this was notably used to describe the disastrous 1902 eruption of Mount Pelée on Martinique, a Frenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Extinctions Since 1500
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the bee hummingbird to the common ostrich. There are over 11,000 living species and they are split into 44 orders. More than half are passerine or "perching" birds. Birds have wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have fur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural History Of The Revillagigedo Islands
Nature is an inherent character or constitution, particularly of the ecosphere or the universe as a whole. In this general sense nature refers to the laws, elements and phenomena of the physical world, including life. Although humans are part of nature, human activity or humans as a whole are often described as at times at odds, or outright separate and even superior to nature. During the advent of modern scientific method in the last several centuries, nature became the passive reality, organized and moved by divine laws. With the Industrial Revolution, nature increasingly became seen as the part of reality deprived from intentional intervention: it was hence considered as sacred by some traditions (Jean-Jacques Rousseau, Rousseau, American transcendentalism) or a mere decorum for divine providence or human history (Hegel, Marx). However, a vitalist vision of nature, closer to the pre-Socratic one, got reborn at the same time, especially after Charles Darwin. Within the var ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct Birds Of North America
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and recover. As a species' potential Range (biology), range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxon, Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the Fossil, fossil record) after a period of apparent absence. Over five billion species are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryotes globally, possibly many times more if microorganisms are included. Notable extinct animal species include Dinosaur, non-avian dinosaurs, Machairodontinae, saber-toothed cats, and mammoths. Through evolution, species arise through the process of specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct Animals Of Mexico
Extinction is the termination of an organism by the death of its last member. A taxon may become functionally extinct before the death of its last member if it loses the capacity to reproduce and recover. As a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. Over five billion species are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryotes globally, possibly many times more if microorganisms are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, and mammoths. Through evolution, species arise through the process of speciation. Species become extinct when they are no longer able to survive in changing conditions or against superior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic Birds Of Western Mexico
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can also be referred to as an ''endemism'' or, in scientific literature, as an ''endemite''. Similarly, many species found in the Western ghats of India are examples of endemism. Endemism is an important concept in conservation biology for measuring biodiversity in a particular place and evaluating the risk of extinction for species. Endemism is also of interest in evolutionary biology, because it provides clues about how changes in the environment cause species to undergo range shifts (potentially expanding their range into a larger area or becomin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salpinctes
The rock wren (''Salpinctes obsoletus'') is a small songbird of the wren family native to western North America, Mexico and Central America. It is the only species in the genus ''Salpinctes''. Description Measurements: * Length: 4.9-5.9 in (12.5-15 cm) * Weight: 0.5-0.6 oz (15-18 g) * Wingspan: 8.7-9.4 in (22-24 cm) They have grey-brown upperparts with small black and white spots and pale grey underparts with a light brown rump. Additional distinctive features include a light grey line over the eye, a long slightly decurved thin bill, a long barred tail and dark legs. They actively hunt on the ground, around and under objects, probing with their bill as their extraction tool. They mainly eat insects and spiders. Its song is a trill that becomes more varied during the nesting season. These birds are permanent residents in the south of their range, but northern populations migrate to warmer areas from the central United States and southwest Canada southwards. They ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condor (journal)
''Ornithological Applications'', formerly ''The Condor'' and ''The Condor: Ornithological Applications'', is a peer-reviewed quarterly scientific journal covering ornithology. It is an official journal of the American Ornithological Society. History The journal was first published in 1899 as the ''Bulletin of the Cooper Ornithological Club'' by the Cooper Ornithological Club (later Cooper Ornithological Society), a California-based ornithological society. In 1900, the journal was renamed as ''The Condor''. It published ornithological research, and through the 1950s, its scope was regional, focusing on the western United States. An editorial board was established in 1951 to address increasing submissions to the journal. James R. King, editor-in-chief following 1965, instituted an external peer review system. Moreover, King broadened the journal's geographic scope. By 1966, at least 40% of papers published in ''The Condor'' were written by scientists outside the United States. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Raven
The common raven or northern raven (''Corvus corax'') is a large all-black passerine bird. It is the most widely distributed of all corvids, found across the Northern Hemisphere. There are 11 accepted subspecies with little variation in appearance, although recent research has demonstrated significant genetic differences among populations from various regions. It is one of the two largest corvids, alongside the thick-billed raven, and is the heaviest passerine bird; at maturity, the common raven averages in length and in weight, though up to in the heaviest individuals. Although their typical lifespan is considerably shorter, common ravens can live more than 23 years in the wild. Young birds may travel in flocks but later mate for life, with each mated pair defending a territory. Common ravens have coexisted with humans for thousands of years and in some areas have been so numerous that people have regarded them as pests. Part of their success as a species is due to their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pumice
Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls, and being dark colored and denser.Jackson, J.A., J. Mehl, and K. Neuendorf (2005) ''Glossary of Geology'' American Geological Institute, Alexandria, Virginia. 800 pp. McPhie, J., M. Doyle, and R. Allen (1993) ''Volcanic Textures A guide to the interpretation of textures in volcanic rocks'' Centre for Ore Deposit and Exploration Studies, University of Tasmania, Hobart, Tasmania..198 pp. Pumice is created when super-heated, highly pressurized rock is rapidly ejected from a volcano. The unusual foamy configuration of pumice happens because of simultaneous rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering the sol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Explosivity Index
The volcanic explosivity index (VEI) is a scale used to measure the size of explosive volcanic eruptions. It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982. Volume of products, eruption cloud height, and qualitative observations (using terms ranging from "gentle" to "mega-colossal") are used to determine the explosivity value. The scale is open-ended with the largest eruptions in history given a magnitude of 8. A value of 0 is given for non-explosive eruptions, defined as less than of tephra ejected; and 8 representing a supervolcanic eruption that can eject (240 cubic miles) of tephra and have a cloud column height of over . The scale is logarithmic, with each interval on the scale representing a tenfold increase in observed ejecta criteria, with the exception of between VEI-0, VEI-1 and VEI-2. Classification With indices running from 0 to 8, the VEI associated with an eruption is dependent on how much volcanic materia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
