The Anatidae are the biological family of water birds that includes ducks and swans. The family has a cosmopolitan distribution, occurring on all the world's continents; these birds are adapted for swimming, floating on the water surface, in some cases diving in at least shallow water. The family contains around 146 species in 43 genera, they are herbivorous, are monogamous breeders. A number of species undertake annual migrations. A few species have been domesticated for agriculture, many others are hunted for food and recreation. Five species have become extinct since 1600, many more are threatened with extinction; the ducks and swans are small- to large-sized birds with a broad and elongated general body plan. Diving species vary from this in being rounder. Extant species range in size from the cotton pygmy goose, at as little as 26.5 cm and 164 g, to the trumpeter swan, at as much as 183 cm and 17.2 kg. The wings are short and pointed, supported by strong wing muscles that generate rapid beats in flight.
They have long necks, although this varies in degree between species. The legs are short and set far to the back of the body, have a leathery feel with a scaly texture. Combined with their body shape, this can make some species awkward on land, but they are stronger walkers than other marine and water birds such as grebes or petrels, they have webbed feet, though a few species such as the Nene have secondarily lost their webbing. The bills are made of soft keratin with a sensitive layer of skin on top. For most species, the shape of the bill tends to be more flattened to a lesser extent; these contain serrated lamellae which are well defined in the filter-feeding species. Their feathers are excellent at shedding water due to special oils. Many of the ducks display sexual dimorphism, with the males being more brightly coloured than the females; the swans and whistling-ducks lack sexually dimorphic plumage. Anatids are vocal birds, producing a range of quacks, honks and trumpeting sounds, depending on species.
Anatids are herbivorous as adults, feeding on various water-plants, although some species eat fish, molluscs, or aquatic arthropods. One group, the mergansers, are piscivorous, have serrated bills to help them catch fish. In a number of species, the young include a high proportion of invertebrates in their diets, but become purely herbivorous as adults; the anatids are seasonal and monogamous breeders. The level of monogamy varies within the family. However, forced extrapair copulation among anatids are common, ocucurring in 55 species in 17 genera. Anatidae is a large proportion of the 3% of bird species to possess a penis, though they vary in size and surface elaboration. Most species are adapted for copulation on the water only, they construct simple nests from whatever material is close at hand lining them with a layer of down plucked from the mother's breast. In most species, only the female incubates the eggs; the young are precocial, are able to feed themselves from birth. One aberrant species, the black-headed duck, is an obligate brood parasite, laying its eggs in the nests of gulls and coots.
While this species never raises its own young, a number of other ducks lay eggs in the nests of conspecifics in addition to raising their own broods. Duck and goose feathers and down have long been popular for bedspreads, sleeping bags, coats; the members of this family have long been used for food. Humans have had a long relationship with ducks and swans. However, some anatids are damaging agricultural pests, have acted as vectors for zoonoses such as avian influenza. Since 1600, five species of ducks have become extinct due to the activities of humans, subfossil remains have shown that humans caused numerous extinctions in prehistory. Today, many more are considered threatened. Most of the historic and prehistoric extinctions were insular species, vulnerable due to small populations, island tameness. Evolving on islands that lacked predators, these species lost antipredator behaviours, as well as the ability to fly, were vulnerable to human hunting pressure and introduced species. Other extinctions and declines are attributable to overhunting, habitat loss and modification, hybridisation with introduced ducks.
Numerous governments and conservation and hunting organisations have made considerable progress in protecting ducks and duck populations through habitat protection and creation and protection, captive-breeding programmes. The family Anatidae was introduced by the English zoologist William Elford Leach in a guide to the contents of the British Museum published in 1820. While the status of the Anatidae as a family is straightforward, which species properly belong to it is little debated, the relationships of the di
Feathers are epidermal growths that form the distinctive outer covering, or plumage, on birds, other extinct species of dinosaurs, pterosaurs. They are considered the most complex integumentary structures found in vertebrates and a premier example of a complex evolutionary novelty, they are among the characteristics. Although feathers cover most of the bird's bodies, they arise only from certain well-defined tracts on the skin, they aid in flight, thermal insulation, waterproofing. In addition, coloration helps in protection. Plumology is the name for the science, associated with the study of feathers. Feathers are among the most complex integumentary appendages found in vertebrates and are formed in tiny follicles in the epidermis, or outer skin layer, that produce keratin proteins; the β-keratins in feathers and claws — and the claws and shells of reptiles — are composed of protein strands hydrogen-bonded into β-pleated sheets, which are further twisted and crosslinked by disulfide bridges into structures tougher than the α-keratins of mammalian hair and hoof.
The exact signals that induce the growth of feathers on the skin are not known, but it has been found that the transcription factor cDermo-1 induces the growth of feathers on skin and scales on the leg. There are two basic types of feather: vaned feathers which cover the exterior of the body, down feathers which are underneath the vaned feathers; the pennaceous feathers are vaned feathers. Called contour feathers, pennaceous feathers arise from tracts and cover the entire body. A third rarer type of feather, the filoplume, is hairlike and are associated with contour feathers and are entirely hidden by them, with one or two filoplumes attached and sprouting from near the same point of the skin as each contour feather, at least on a bird's head and trunk. In some passerines, filoplumes arise exposed beyond the contour feathers on the neck; the remiges, or flight feathers of the wing, rectrices, the flight feathers of the tail are the most important feathers for flight. A typical vaned feather features a main shaft, called the rachis.
Fused to the rachis are a series of branches, or barbs. These barbules have minute hooks called barbicels for cross-attachment. Down feathers are fluffy because they lack barbicels, so the barbules float free of each other, allowing the down to trap air and provide excellent thermal insulation. At the base of the feather, the rachis expands to form the hollow tubular calamus which inserts into a follicle in the skin; the basal part of the calamus is without vanes. This part is embedded within the skin follicle and has an opening at the base and a small opening on the side. Hatchling birds of some species have a special kind of natal down feathers which are pushed out when the normal feathers emerge. Flight feathers are stiffened so as to work against the air in the downstroke but yield in other directions, it has been observed that the orientation pattern of β-keratin fibers in the feathers of flying birds differs from that in flightless birds: the fibers are better aligned along the shaft axis direction towards the tip, the lateral walls of rachis region show structure of crossed fibers.
Feathers insulate birds from water and cold temperatures. They may be plucked to line the nest and provide insulation to the eggs and young; the individual feathers in the wings and tail play important roles in controlling flight. Some species have a crest of feathers on their heads. Although feathers are light, a bird's plumage weighs two or three times more than its skeleton, since many bones are hollow and contain air sacs. Color patterns serve as camouflage against predators for birds in their habitats, serve as camouflage for predators looking for a meal; as with fish, the top and bottom colors may be different, in order to provide camouflage during flight. Striking differences in feather patterns and colors are part of the sexual dimorphism of many bird species and are important in selection of mating pairs. In some cases there are differences in the UV reflectivity of feathers across sexes though no differences in color are noted in the visible range; the wing feathers of male club-winged manakins Machaeropterus deliciosus have special structures that are used to produce sounds by stridulation.
Some birds have a supply of powder down feathers which grow continuously, with small particles breaking off from the ends of the barbules. These particles produce a powder that sifts through the feathers on the bird's body and acts as a waterproofing agent and a feather conditioner. Powder down has evolved independently in several taxa and can be found in down as well as in pennaceous feathers, they may be scattered in plumage as in the pigeons and parrots or in localized patches on the breast, belly, or flanks, as in herons and frogmouths. Herons use their bill to break the powder down feathers and to spread them, while cockatoos may use their head as a powder puff to apply the powder. Waterproofing can be lost by exposure to emulsifying agents due to human pollution. Feathers can become waterlogged, causing the bird to sink, it is very difficult to clean and rescue birds whose feathers have been fouled by oil spills. The feathers of cormorants soak up water and help to reduce buoyancy, thereby allowing the birds to swim submerged.
Bristles are stiff. Rictal bristles are found around bill, they may serve a similar purpose to e
Oregon is a state in the Pacific Northwest region on the West Coast of the United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho; the parallel 42 ° north delineates the southern boundary with Nevada. Oregon is one of only four states of the continental United States to have a coastline on the Pacific Ocean. Oregon was inhabited by many indigenous tribes before Western traders and settlers arrived. An autonomous government was formed in the Oregon Country in 1843 before the Oregon Territory was created in 1848. Oregon became the 33rd state on February 14, 1859. Today, at 98,000 square miles, Oregon is the ninth largest and, with a population of 4 million, 27th most populous U. S. state. The capital, Salem, is the second most populous city in Oregon, with 169,798 residents. Portland, with 647,805, ranks as the 26th among U. S. cities. The Portland metropolitan area, which includes the city of Vancouver, Washington, to the north, ranks the 25th largest metro area in the nation, with a population of 2,453,168.
Oregon is one of the most geographically diverse states in the U. S. marked by volcanoes, abundant bodies of water, dense evergreen and mixed forests, as well as high deserts and semi-arid shrublands. At 11,249 feet, Mount Hood, a stratovolcano, is the state's highest point. Oregon's only national park, Crater Lake National Park, comprises the caldera surrounding Crater Lake, the deepest lake in the United States; the state is home to the single largest organism in the world, Armillaria ostoyae, a fungus that runs beneath 2,200 acres of the Malheur National Forest. Because of its diverse landscapes and waterways, Oregon's economy is powered by various forms of agriculture and hydroelectric power. Oregon is the top timber producer of the contiguous United States, the timber industry dominated the state's economy in the 20th century. Technology is another one of Oregon's major economic forces, beginning in the 1970s with the establishment of the Silicon Forest and the expansion of Tektronix and Intel.
Sportswear company Nike, Inc. headquartered in Beaverton, is the state's largest public corporation with an annual revenue of $30.6 billion. The earliest evidence of the name Oregon has Spanish origins; the term "orejón" comes from the historical chronicle Relación de la Alta y Baja California written by the new Spaniard Rodrigo Montezuma and made reference to the Columbia River when the Spanish explorers penetrated into the actual North American territory that became part of the Viceroyalty of New Spain. This chronicle is the first topographical and linguistic source with respect to the place name Oregon. There are two other sources with Spanish origins, such as the name Oregano, which grows in the southern part of the region, it is most probable that the American territory was named by the Spaniards, as there are some populations in Spain such as "Arroyo del Oregón" considering that the individualization in Spanish language "El Orejón" with the mutation of the letter "g" instead of "j". Another early use of the name, spelled Ouragon, was in a 1765 petition by Major Robert Rogers to the Kingdom of Great Britain.
The term referred to the then-mythical River of the West. By 1778, the spelling had shifted to Oregon. In his 1765 petition, Rogers wrote: The rout...is from the Great Lakes towards the Head of the Mississippi, from thence to the River called by the Indians Ouragon... One theory is that the name comes from the French word ouragan, applied to the River of the West based on Native American tales of powerful Chinook winds on the lower Columbia River, or from firsthand French experience with the Chinook winds of the Great Plains. At the time, the River of the West was thought to rise in western Minnesota and flow west through the Great Plains. Joaquin Miller explained in Sunset magazine, in 1904, how Oregon's name was derived: The name, Oregon, is rounded down phonetically, from Ouve água—Oragua, Or-a-gon, Oregon—given by the same Portuguese navigator that named the Farallones after his first officer, it in a large way, means cascades:'Hear the waters.' You should steam up the Columbia and hear and feel the waters falling out of the clouds of Mount Hood to understand the full meaning of the name Ouve a água, Oregon.
Another account, endorsed as the "most plausible explanation" in the book Oregon Geographic Names, was advanced by George R. Stewart in a 1944 article in American Speech. According to Stewart, the name came from an engraver's error in a French map published in the early 18th century, on which the Ouisiconsink River was spelled "Ouaricon-sint", broken on two lines with the -sint below, so there appeared to be a river flowing to the west named "Ouaricon". According to the Oregon Tourism Commission, present-day Oregonians pronounce the state's name as "or-uh-gun, never or-ee-gone". After being drafted by the Detroit Lions in 2002, former Oregon Ducks quarterback Joey Harrington distributed "Orygun" stickers to members of the media as a reminder of how to pronounce the name of his home state; the stickers are sold by the University of Oregon Bookstore. Oregon is 295 miles north to south at longest distance, 395 miles east to west. With an area of 98,381 square miles, Oregon is larger than the United Kingdom.
It is the ninth largest state in the United States. Oregon's highest point is the summit of Mount Hood, at 11,249 feet, its lowest point is the sea level of the Pacific Ocean along the Oregon Coas
IUCN Red List
The IUCN Red List of Threatened Species, founded in 1965, has evolved to become the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of criteria to evaluate the extinction risk of thousands of subspecies; these criteria are relevant to all species and all regions of the world, With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. A series of Regional Red List are produced by countries or organizations, which assess the risk of extinction to species within a political management unit; the IUCN Red List is set upon precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all regions of the world; the aim is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to try to reduce species extinction. According to the International Union for Conservation of Nature, the formally stated goals of the Red List are to provide scientifically based information on the status of species and subspecies at a global level, to draw attention to the magnitude and importance of threatened biodiversity, to influence national and international policy and decision-making, to provide information to guide actions to conserve biological diversity.
Major species assessors include BirdLife International, the Institute of Zoology, the World Conservation Monitoring Centre, many Specialist Groups within the IUCN Species Survival Commission. Collectively, assessments by these organizations and groups account for nearly half the species on the Red List; the IUCN aims to have the category of every species re-evaluated every five years if possible, or at least every ten years. This is done in a peer reviewed manner through IUCN Species Survival Commission Specialist Groups, which are Red List Authorities responsible for a species, group of species or specific geographic area, or in the case of BirdLife International, an entire class; as of 2018, 26,197 species are now classified critical or endangered. The 1964 IUCN Red List of Threatened Plants used the older pre-criteria Red List assessment system. Plants listed may not, appear in the current Red List. IUCN advise that it is best to check both the online Red List and the 1997 plants Red List publication.
The 2006 Red List, released on 4 May 2006 evaluated 40,168 species as a whole, plus an additional 2,160 subspecies, aquatic stocks, subpopulations. On 12 September 2007, the World Conservation Union released the 2007 IUCN Red List of Threatened Species. In this release, they have raised their classification of both the western lowland gorilla and the Cross River gorilla from endangered to critically endangered, the last category before extinct in the wild, due to Ebola virus and poaching, along with other factors. Russ Mittermeier, chief of Swiss-based IUCN's Primate Specialist Group, stated that 16,306 species are endangered with extinction, 188 more than in 2006; the Red List includes the Sumatran orangutan in the Critically Endangered category and the Bornean orangutan in the Endangered category. The 2008 Red List was released on 6 October 2008, at the IUCN World Conservation Congress in Barcelona, "has confirmed an extinction crisis, with one in four at risk of disappearing forever"; the study shows at least 1,141 of the 5,487 mammals on Earth are known to be threatened with extinction, 836 are listed as Data Deficient.
The Red List of 2012 was released 19 July 2012 at Rio+20 Earth Summit. The IUCN assessed a total of 63,837 species. 3,947 were described as "critically endangered" and 5,766 as "endangered," while more than 10,000 species are listed as "vulnerable." At threat are 41% of amphibian species, 33% of reef-building corals, 30% of conifers, 25% of mammals, 13% of birds. The IUCN Red List has listed 132 species of plants and animals from India as "Critically Endangered." Species are classified by the IUCN Red List into nine groups, specified through criteria such as rate of decline, population size, area of geographic distribution, degree of population and distribution fragmentation. There is an emphasis on the acceptability of applying any criteria in the absence of high quality data including suspicion and potential future threats, "so long as these can reasonably be supported." Extinct – beyond reasonable doubt that the species is no longer extant. Extinct in the wild – survives only in captivity, cultivation and/or outside native range, as presumed after exhaustive surveys.
Critically endangered – in a and critical state. Endangered – high risk of extinction in the wild, meets any of criteria A to E for Endangered. Vulnerable – meets one of the 5 red list criteria and thus considered to be at high risk of unnatural extinction without further human intervention. Near threatened – close to being at high risk of extinction in the near future. Least concern – unlikely to become extinct in the near future. Data deficient Not evaluated In the IUCN Red List, "threatened" embraces the categories of Critically Endangered and Vulnerable; the older 1994 list has only a single "Lower Risk" category which contained three subcategories: Conservation Depe
The green-winged teal is a common and widespread duck that breeds in the northern areas of North America except on the Aleutian Islands. It was considered conspecific with the common teal for some time but the issue is still being reviewed by the American Ornithological Society. However, nearly all other authorities consider it distinct based on behavioral and molecular evidence; the scientific name is from Latin Anas, "duck" and carolinensis, "of Carolina". This dabbling duck is migratory and winters far south of its breeding range, it is gregarious outside of the breeding season and will form large flocks. In flight, the fast, twisting flocks resemble waders; this is the smallest North American dabbling duck. The breeding male has grey flanks and back, with a yellow rear end and a white-edged green speculum, obvious in flight or at rest, it has a chestnut head with a green eye patch. It is distinguished from drake common teals by a vertical white stripe on side of breast, the lack of both a horizontal white scapular stripe and the lack of thin buff lines on its head.
The females are light brown, with plumage much like a female mallard. They can be distinguished from most ducks on size and the speculum. Separation from female common teal is problematic. In non-breeding plumage, the drake looks more like the female, it is a common duck of sheltered wetlands, such as taiga bogs, feeds by dabbling for plant food or grazing. It nests near water and under cover. While its conservation status is not evaluated by IUCN at present due to non-recognition of the taxon, it is plentiful enough to make it a species of Least Concern if it were, it can be seen in vast numbers in a main wintering area. This is a noisy species; the male has a clear whistle. All three green-winged teal subspecies occur in the northern hemisphere during summer and in winter extend to northern South America, central Africa, southern India and the Philippines. In North America, ssp. carolinensis occurs across the continent and is joined in the Aleutian Islands by ssp. nimia, which remains there throughout the year.
Anas crecca breeds in Iceland and Asia. It is seen during the winter in North America along the Atlantic Coast; the American green-winged teal breeds from the Aleutian Islands, northern Alaska, Mackenzie River delta, northern Saskatchewan, Ontario and Labrador south to central California, central Nebraska, central Kansas, southern Minnesota, Ontario, Quebec and the Maritime Provinces. The American green-winged teal winters from southern Alaska and southern British Columbia east to New Brunswick and Nova Scotia and south to Central America, it winters in Hawaii. There is a single photographic record from South America. Green-winged teal are abundant in wetlands of the Canadian parkland and northern boreal forest associations, they occur more in mixed-prairie associations than in shortgrass associations. They inhabit arctic tundra and semidesert communities. Within the above associations, green-winged teal inhabit wetland communities dominated by bulrushes, sedges and other emergent and aquatic vegetation.
Green-winged teal nest in grasses, sedge meadows, or on dry hillsides having brush or aspen cover. Near Brooks, green-winged teal nests were found most in beds of rushes, in western Montana most nests were located under greasewood. Nesting chronology varies geographically. In North Dakota, green-winged teal begin nesting in late April. In the Northwest Territories, green-winged teal begin nesting between late May and early July. At Minto Lakes, green-winged teal initiate nesting as early as June 1 and as late as July 20. Green-winged teal become sexually mature their first winter, they lay 5 to 16 eggs. The incubation period is 21 to 23 days. Green-winged teals fledge 34 to 35 days after hatching or before 6 weeks of age. Young green-winged teal have the fastest growth rate of all ducks. Male green-winged teal leave females at the start of incubation and congregate on safe waters to molt; some populations undergo an extensive molt migration while others remain on or near breeding grounds. Females molt on breeding grounds.
Green-winged teal are among the earliest spring migrants. They arrive on nesting areas as soon as the snow melts. In early February, green-winged teal begin to depart their winter grounds, continue through April. In central regions green-winged teal begin to arrive early in March with peak numbers in early April. In northern areas of the United States, green-winged teal migrating to wintering grounds appear in early September through mid-December, they begin migrating into most central regions during September and remain through December. On their more southerly winter areas, green-winged teal arrive as early as late September, but most do not appear until late November. Green-winged teal inhabit inland lakes, ponds and shallow streams with dense emergent and aquatic vegetation, they prefer shallow waters and small pools during the breeding season. Green-winged teal are found resting on mudbanks or stumps, or perching on low limbs of dead trees; these ducks nest in depressions on dry ground located at the base of shrubs, under a log, or in dense grass.
South America is a continent in the Western Hemisphere in the Southern Hemisphere, with a small portion in the Northern Hemisphere. It may be considered a subcontinent of the Americas, how it is viewed in the Spanish and Portuguese-speaking regions of the Americas; the reference to South America instead of other regions has increased in the last decades due to changing geopolitical dynamics. It is bordered on the west on the north and east by the Atlantic Ocean, it includes twelve sovereign states, a part of France, a non-sovereign area. In addition to this, the ABC islands of the Kingdom of the Netherlands and Tobago, Panama may be considered part of South America. South America has an area of 17,840,000 square kilometers, its population as of 2016 has been estimated at more than 420 million. South America ranks fourth in fifth in population. Brazil is by far the most populous South American country, with more than half of the continent's population, followed by Colombia, Argentina and Peru. In recent decades Brazil has concentrated half of the region's GDP and has become a first regional power.
Most of the population lives near the continent's western or eastern coasts while the interior and the far south are sparsely populated. The geography of western South America is dominated by the Andes mountains. Most of the continent lies in the tropics; the continent's cultural and ethnic outlook has its origin with the interaction of indigenous peoples with European conquerors and immigrants and, more locally, with African slaves. Given a long history of colonialism, the overwhelming majority of South Americans speak Portuguese or Spanish, societies and states reflect Western traditions. South America occupies the southern portion of the Americas; the continent is delimited on the northwest by the Darién watershed along the Colombia–Panama border, although some may consider the border instead to be the Panama Canal. Geopolitically and geographically all of Panama – including the segment east of the Panama Canal in the isthmus – is included in North America alone and among the countries of Central America.
All of mainland South America sits on the South American Plate. South America is home to Angel Falls in Venezuela. South America's major mineral resources are gold, copper, iron ore and petroleum; these resources found in South America have brought high income to its countries in times of war or of rapid economic growth by industrialized countries elsewhere. However, the concentration in producing one major export commodity has hindered the development of diversified economies; the fluctuation in the price of commodities in the international markets has led to major highs and lows in the economies of South American states causing extreme political instability. This is leading to efforts to diversify production to drive away from staying as economies dedicated to one major export. South America is one of the most biodiverse continents on earth. South America is home to many interesting and unique species of animals including the llama, piranha, vicuña, tapir; the Amazon rainforests possess high biodiversity, containing a major proportion of the Earth's species.
Brazil is the largest country in South America, encompassing around half of the continent's land area and population. The remaining countries and territories are divided among three regions: The Andean States, the Guianas and the Southern Cone. Traditionally, South America includes some of the nearby islands. Aruba, Curaçao, Trinidad and the federal dependencies of Venezuela sit on the northerly South American continental shelf and are considered part of the continent. Geo-politically, the island states and overseas territories of the Caribbean are grouped as a part or subregion of North America, since they are more distant on the Caribbean Plate though San Andres and Providencia are politically part of Colombia and Aves Island is controlled by Venezuela. Other islands that are included with South America are the Galápagos Islands that belong to Ecuador and Easter Island, Robinson Crusoe Island, Chiloé and Tierra del Fuego. In the Atlantic, Brazil owns Fernando de Noronha and Martim Vaz, the Saint Peter and Saint Paul Archipelago, while the Falkland Islands are governed by the United Kingdom, whose sovereignty over the islands is disputed by Argentina.
South Georgia and the South Sandwich Islands may be associate