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Hardhead (coin)
The hardhead (''Aythya australis''), also known as the white-eyed duck, is the only true diving duck found in Australia. The common name "hardhead" has nothing to do with the density of the bird's skull, instead referring to the difficulty encountered by early taxidermists in processing the head. Hardheads are found in wetter, coastal regions of Australia, particularly in the south-east, but are known to disperse as far afield as New Guinea, New Zealand, and the Pacific Islands. Description Hardheads are smaller than most ducks, usually not reaching much more than 45 cm long but sometimes reaching 60 cm, and noticeably more rounded in overall form than most ducks. Both male and female are a fairly uniform chocolate-brown above, with rufous flanks and white undersides (which are often not visible if the duck is in the water). The trailing edges and almost the entire underside of the wings are white. In the male, the eyes are a striking white, in the female, brown. Di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Campbell Eyton
Thomas Campbell Eyton JP, DL (10 September 1809 – 25 October 1880) was an English naturalist whose fields were cattle, fishes and birds. He was a friend and correspondent of Charles Darwin though he opposed his theories. Eyton was born at Eyton Hall, near Wellington, Shropshire. He studied at St John's College, Cambridge, where he was a contemporary and friend of Charles Darwin. After succeeding to the estate in 1855 Eyton built a large natural history museum at Eyton Hall that included a range of bird skins and skeletons, described as "one of the finest in Europe". Besides Darwin, Eyton enjoyed a correspondence with other naturalists including Louis Agassiz, Asa Gray and Alfred Russel Wallace. Eyton published ''History of the Rarer British Birds'' (1836), ''A Monograph on the Anatidae, Or Duck Tribe'' (1838), ''A History of Oyster and Oyster Fisheries'' (1858) and ''Osteologia Avium'' (1871–78). He established in about 1842 the ''Herd Book of Hereford Cattle'', which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drought
A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, and O. Zolina, 2021Water Cycle Changes In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1055–1210, doi:10.1017/9781009157896.010. This means that a drought is "a moisture deficit relative to the average water availability at a given location and season". A drought can last for days, months or years. Drought ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birds Of Australia
Australia and its offshore islands and territories have 898 recorded bird species as of 2014. Of the recorded birds, 165 are considered vagrant or accidental visitors, of the remainder over 45% are classified as Australian endemics: found nowhere else on earth. It has been suggested that up to 10% of Australian bird species may go extinct by the year 2100 as a result of climate change. Australian species range from the tiny weebill to the huge, flightless emu. Many species of Australian birds will immediately seem familiar to visitors from the Northern Hemisphere: Australian wrens look and act much like northern wrens, and Australian robins seem to be close relatives of the northern robins. However, the majority of Australian passerines are descended from the ancestors of the crow family, and the close resemblance is misleading: the cause is not genetic relatedness but convergent evolution. For example, almost any land habitat offers a nice home for a small bird that specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birds Described In 1838
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. Birds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aythya
''Aythya'' is a genus of diving ducks. It has twelve described species. The name ''Aythya'' comes from the Ancient Greek word (), which may have referred to a sea-dwelling duck or an auklet. ''Aythya shihuibas'' was described from the Late Miocene of China. Zelenkov (2016) transferred the species ''Anas denesi'' Kessler (2013), known from the late Miocene of Hungary, to the genus ''Aythya''. An undescribed prehistoric species is known only from Early Pleistocene fossil remains found at Dursunlu, Turkey; it might however be referrable to a paleosubspecies of an extant species considering its age (see also Greater scaup). The Miocene ''"Aythya" arvernensis'' is now placed in '' Mionetta'', while ''"Aythya" chauvirae'' seems to contain the remains of two species, at least one of which does not seem to be a diving duck. The genus ''Aythya'' was introduced in 1822 by the German zoologist Friedrich Boie. The type species is the greater scaup. ''Aythya'' species The genus contains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pochard , ''Netta erythrophthalma''
{{Animal common name ...
Pochard is a common name used for several species of diving ducks: *Four species in the genus ''Aythya'': ** Common pochard, ''Aythya ferina'' ** Baer's pochard, ''Aythya baeri'' ** Ferruginous pochard, ''Aythya nyroca'' ** Madagascar pochard, ''Aythya innotata'' * Three species in the genus ''Netta'': ** Red-crested pochard, ''Netta rufina'' ** Rosy-billed pochard or Rosybill, ''Netta peposaca'' ** Southern pochard The southern pochard (''Netta erythrophthalma'') is a species of duck, and a member of the genus '' Netta''. There are two subspecies, the South American (southern) pochard ''N. e. erythrophthalma'' (Wied-Neuwied, 1833) and the African (southern) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUCN Red List Of Threatened Species
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of precise criteria to evaluate the extinction risk of thousands of species and 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 Lists are produced by countries or organizations, which assess the risk of extinction to species within a political management unit. The aim of the International Union for Conservation of Nature, IUCN Red List is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to reduce species extinction. According to International Unio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Least Concern
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. They do not qualify as threatened, near threatened, or (before 2001) conservation dependent. Species cannot be assigned the "Least Concern" category unless they have had their population status evaluated. That is, adequate information is needed to make a direct, or indirect, assessment of its risk of extinction based on its distribution or population status. Evaluation Since 2001 the category has had the abbreviation "LC", following the IUCN 2001 Categories & Criteria (version 3.1). Before 2001 "least concern" was a subcategory of the "Lower Risk" category and assigned the code "LR/lc" or lc. Around 20% of least concern taxa (3261 of 15636) in the IUCN database still use the code "LR/lc", which indicates they have not been re-evaluate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Mayr
Ernst Walter Mayr (; 5 July 1904 – 3 February 2005) was one of the 20th century's leading evolutionary biologists. He was also a renowned Taxonomy (biology), taxonomist, tropical explorer, ornithologist, Philosophy of biology, philosopher of biology, and History of science, historian of science. His work contributed to the conceptual revolution that led to the Modern synthesis (20th century), modern evolutionary synthesis of Gregor Mendel, Mendelian genetics, systematics, and Charles Darwin, Darwinian evolution, and to the development of the Species, biological species concept. Although Charles Darwin and others posited that multiple species could evolve from a single common ancestor, the mechanism by which this occurred was not understood, creating the ''species problem''. Ernst Mayr approached the problem with a new definition for species. In his book ''Systematics and the Origin of Species'' (1942) he wrote that a species is not just a group of Morphology (biology), morph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duck
Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form taxon; they do not represent a monophyletic group (the group of all descendants of a single common ancestral species), since swans and geese are not considered ducks. Ducks are mostly aquatic birds, and may be found in both fresh water and sea water. Ducks are sometimes confused with several types of unrelated water birds with similar forms, such as loons or divers, grebes, gallinules and coots. Etymology The word ''duck'' comes from Old English 'diver', a derivative of the verb 'to duck, bend down low as if to get under something, or dive', because of the way many species in the dabbling duck group feed by upending; compare with Dutch and German 'to dive'. This word replaced Old English / 'duck', possibly to avoid confusion with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacific Islands
Collectively called the Pacific Islands, the islands in the Pacific Ocean are further categorized into three major island groups: Melanesia, Micronesia, and Polynesia. Depending on the context, the term ''Pacific Islands'' may refer to one of several different concepts: (1) those countries and islands with common Austronesian origins, (2) the islands once (or currently) colonized, or (3) the geographical region of Oceania. This list of islands in the Pacific Ocean is organized by archipelago or border, political boundary. In order to keep this list of moderate size, the more complete lists for countries with large numbers of small or uninhabited islands have been hyperlinked. Name ambiguity and groupings The umbrella term ''Pacific Islands'' has taken on several meanings. Sometimes it is used to refer only to the islands defined as lying within Oceania Oceania (, , ) is a region, geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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