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Stejneger's Scoter
Stejneger's scoter (''Melanitta stejnegeri''), also known as the Siberian scoter, is a large sea duck. The genus name is derived from Ancient Greek ''melas'' "black" and ''netta'' "duck". Taxonomy Stejneger's scoter was described by the American ornithologist Robert Ridgway in 1887 and given the binomial name ''Oidemia stejnegeri''. The specific name was chosen to honour the Norwegian born ornithologist Leonhard Stejneger. It was formerly considered to be conspecific with the white-winged scoter. It was suggested to be a full species, according to a new study. Description There are a number of differing characteristics of Stejneger's scoter and the white-winged scoter. Males of the white-winged scoter have browner flanks, dark yellow coloration of most of the bill and a less tall bill knob, approaching the velvet scoter. Stejneger's scoter has a very tall knob at the base of its mostly orange-yellow bill. Females are identical in the field. Distribution Stejneger's scoter bree ... [...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 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'' (1912). Ornitholo ... [...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] |
Birds Of North Asia
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 ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have 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 further evolved for swimming. Bird ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melanitta
The scoters are stocky seaducks in the genus ''Melanitta''. The drakes are mostly black and have swollen bills, the females are brown. They breed in the far north of Europe, Asia, and North America, and winter farther south in temperate zones of those continents. They form large flocks on suitable coastal waters. These are tightly packed, and the birds tend to take off together. Their lined nests are built on the ground close to the sea, lakes or rivers, in woodland or tundra. These species dive for crustaceans and molluscs. Taxonomy The genus ''Melanitta'' was introduced by the German zoologist Friedrich Boie in 1822. The type species was designated in 1838 as the velvet scoter by Thomas Campbell Eyton. The genus name combines the Ancient Greek ''melas'' meaning "black" and ''netta'' meaning "duck". The genus contains six species: The presumed fossil "scoter" ''Melanitta ceruttii'', which lived in California during the Late Pliocene, is now placed in the genus ''Histrionicus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusc
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The gastropods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. Their blood is not totally contained in vessels; some circulates in an open cavity known as the haemocoel. Insects are the most diverse group of animals; they include more than a million described species and represent more than half of all known living organisms. The total number of extant species is estimated at between six and ten million; In: potentially over 90% of the animal life forms on Earth are insects. Insects may be found in nearly all environments, although only a small number of species reside in the oceans, which are dominated by another arthropod group, crustaceans, which recent research has indicated insects are nested within. Nearly all insects hatch from eggs. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. Some crustaceans (Remipedia, Cephalocarida, Branchiopoda) are more closely related to insects and the other hexapods than they are to certain other crustaceans. The 67,000 described species range in size from '' Stygotantulus stocki'' at , to the Japanese spider crab with a leg span of up to and a mass of . Like other arthropods, crustaceans have an exoskeleton, which they moult to grow. They are distinguished from other groups of arthropods, such as insects, myriapods and chelicerates, by the possession of biramous (two-parted) limbs, and by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperate
In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout the year and more distinct seasonal changes compared to tropical climates, where such variations are often small and usually only have precipitation changes. In temperate climates, not only do latitudinal positions influence temperature changes, but sea currents, prevailing wind direction, continentality (how large a landmass is) and altitude also shape temperate climates. The Köppen climate classification defines a climate as "temperate" C, when the mean temperature is above but below in the coldest month to account for the persistency of frost. However, other climate classifications set the minimum at . Zones and climates The north temperate zone extends from the Tropic of Cancer (approximately 23.5° north latitude) to the Arctic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yenisey
The Yenisey (russian: Енисе́й, ''Yeniséy''; mn, Горлог мөрөн, ''Gorlog mörön''; Buryat: Горлог мүрэн, ''Gorlog müren''; Tuvan: Улуг-Хем, ''Uluğ-Hem''; Khakas: Ким суғ, ''Kim suğ''; Ket: Ӄук, ''Quk''; Nenets: Ензя-ям’, ''Enzja-jam''), also romanised as Yenisei, Enisei, or Jenisej, is the fifth-longest river system in the world, and the largest to drain into the Arctic Ocean. Rising in Mungaragiyn-gol in Mongolia, it follows a northerly course before draining into the Yenisey Gulf in the Kara Sea. The Yenisey divides the Western Siberian Plain in the west from the Central Siberian Plateau to the east; it drains a large part of central Siberia. It is the central one of three large Siberian rivers that flow into the Arctic Ocean (the other two being the Ob and the Lena). The maximum depth of the Yenisey is and the average depth is . The depth of river outflow is and inflow is . Geography The Yenisey proper, from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merginae
The sea ducks (''Mergini'') are a tribe of the duck subfamily of birds, the Anatinae. The taxonomy of this group is incomplete. Some authorities separate the group as a subfamily, while others remove some genera. Most species within the group spend their winters near coastal waters. Many species have developed specialized salt glands to allow them to tolerate salt water, but these are poorly developed in juveniles. Some of the species prefer riverine habitats. All but two of the 22 species in this group live in far northern latitudes. The fish-eating members of this group, such as the mergansers and smew, have serrated edges to their bills to help them grip their prey and are often known as "sawbills". Other sea ducks forage by diving underwater, taking molluscs or crustaceans from the sea floor. The Mergini take on the eclipse plumage during the late summer and molt into their breeding plumage during the winter. Species There are twenty-two species in ten genera: *Genus ''Clang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area of , about 30% of Earth's total land area and 8.7% of Earth's total surface area. The continent, which has long been home to the majority of the human population, was the site of many of the first civilizations. Its 4.7 billion people constitute roughly 60% of the world's population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, and on the north by the Arctic Ocean. The border of Asia with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. It is somewhat arbitrary and has moved since its first conception in classical antiquity. The division of Eurasia into two continents reflects East–West cultural, linguistic, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White-winged Scoter
The white-winged scoter (''Melanitta deglandi'') is a large sea duck. The genus name is derived from Ancient Greek ''melas'' "black" and ''netta'' "duck". The species name commemorates French ornithologist Côme Damien Degland. Description The white-winged scoter is one of three North American scoter species and the largest species of scoter. Females range from and , averaging and . The male ranges from and from , averaging and . The white-winged scoter has a wingspan of 31.5 in (80 cm). This species is characterized by its bulky shape and large bill, which is feathered at the gape unlike the blocky bill base of the surf scoter. The white secondary flight feathers by which the species is named is visible in flight, but may be concealed when swimming. The male is all black, except for white around the eye and a white speculum. The bill is orange and red with a large black knob at the base. It takes 3 years for definitive (adult) plumage to be attained - second-year m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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