|
Lesser Scaup
The lesser scaup (''Aythya affinis'') is a small North American diving duck that migrates south as far as Central America in winter. It is colloquially known as the little bluebill or broadbill because of its distinctive blue bill. The origin of the name scaup may stem from the bird's preference for feeding on scalp—the Scottish word for clams, oysters, and mussels; however, some credit it to the female's discordant scaup call as the name's source. It is apparently a very close relative of the Holarctic greater scaup or "bluebill" (''A. marila''), with which it forms a superspecies. The scientific name is derived from Ancient Greek ''aithuia'' an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin, ''affinis'' "related to", from its resemblance to the greater scaup. Description Adults are long, on average. The species can weigh ; males weigh on average and females weigh noticeably less, at on average. Wing lengths (not wingspans) are abou ... [...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] |
Olive (color)
Olive is a dark yellowish-green color, like that of unripe or green olives. As a color word in the English language, it appears in late Middle English. Shaded toward gray, it becomes olive drab. Variations Olivine Olivine is the typical color of the mineral olivine. The first recorded use of ''olivine'' as a color name in English was in 1912. Olive drab Olive drab is variously described as a "dull olive-green colour" (''Oxford English Dictionary'');''Oxford English Dictionary'', 5th Edition, 1982 "a shade of greenish-brown" (''Webster's New World Dictionary''); "a dark gray-green" (''MacMillan English dictionary''); "a grayish olive to dark olive brown or olive gray" (''American Heritage Dictionary''); or "A dull but fairly strong gray-green color" (''Collins English Dictionary''). It was widely used as a camouflage color for uniforms and equipment in the armed forces, particularly by the U.S. Army during the Second World War. The first recorded use of ''oliv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatric
In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation. Such speciation may be a product of reproductive isolation – which prevents hybrid offspring from being viable or able to reproduce, thereby reducing gene flow – that results in genetic divergence. Sympatric speciation may, but need not, arise through secondary contact, which refers to speciation or divergence in allopatry followed by range expansions leading to an area of sympatry. Sympatric species or taxa in secondary contact may or may not interbreed. Types of populations Four main types of population pairs exist in nature. Sympatric populations (or species) contrast with parapatric populations, which contact one another in adjacent but not shared ranges and do n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Sequence
DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. The advent of rapid DNA sequencing methods has greatly accelerated biological and medical research and discovery. Knowledge of DNA sequences has become indispensable for basic biological research, DNA Genographic Projects and in numerous applied fields such as medical diagnosis, biotechnology, forensic biology, virology and biological systematics. Comparing healthy and mutated DNA sequences can diagnose different diseases including various cancers, characterize antibody repertoire, and can be used to guide patient treatment. Having a quick way to sequence DNA allows for faster and more individualized medical care to be administered, and for more organisms to be identified and cataloged. The rapid speed of sequencing attained with modern D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tufted Duck
The tufted duck or tufted pochard (''Aythya fuligula'') is a small diving duck with a population of close to one million birds, found in northern Eurasia. The scientific name is derived from Ancient Greek '' aithuia'', an unidentified seabird mentioned by authors including Hesychius and Aristotle, and ''Latin'' ''fuligo'' "soot" and ''gula'' "throat". Description The adult male is all black except for white flanks and a blue-grey bill with gold-yellow eyes, along with a thin crest on the back of its head. It has an obvious head tuft that gives the species its name. The adult female is brown with paler flanks, and is more easily confused with other diving ducks. In particular, some have white around the bill base which resembles the scaup species, although the white is never as extensive as in those ducks. The females' call is a harsh, growling "karr", mostly given in flight. The males are mostly silent but they make whistles during courtship based on a simple "wit-oo". The only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ring-necked Duck
The ring-necked duck (''Aythya collaris'') is a diving duck from North America commonly found in freshwater ponds and lakes. The scientific name is derived from Greek , an unidentified seabird mentioned by authors including Hesychius and Aristotle, and Latin ''collaris'', "of the neck" from ''collum'', "neck". Description Ring-necked ducks are small to medium-sized diving ducks with the following length, weight, and wingspan measurements: * Length: 15.3-18.1 in (39-46 cm) * Weight: 17.3-32.1 oz (490-910 g) * Wingspan: 24.4-24.8 in (62-63 cm) The adult male is similar in color pattern to the Eurasian tufted duck, its relative. Males are a little bit bigger than the female. It has two white rings surrounding its gray bill, a shiny black angular head, black back, white line on the wings, a white breast and yellow eyes. The adult female has a grayish brown angular head and body with a dark brown back, a dark bill with a more subtle light band than the male, grayish-b ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dabbling Duck
The Anatinae are a subfamily of the family Anatidae (swans, geese and ducks). Its surviving members are the dabbling ducks, which feed mainly at the surface rather than by diving. The other members of the Anatinae are the extinct moa-nalo, a young but highly apomorphic lineage derived from the dabbling ducks. There has been much debate about the systematical status and which ducks belong to the Anatinae. Some taxonomic authorities only include the dabbling ducks and their close relatives, the extinct moa-nalos. Alternatively, the Anatinae are considered to include most "ducks", and the dabbling ducks form a tribe Anatini within these. The classification as presented here more appropriately reflects the remaining uncertainty about the interrelationships of the major lineages of Anatidae (waterfowl). Systematics The dabbling duck group, of worldwide distribution, was delimited in a 1986 study to include eight genera and some 50–60 living species. However, Salvadori's teal i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supercilium
The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head.Dunn and Alderfer (2006), p. 10 Also known as an "eyebrow", it is distinct from the eyestripe, which is a line that runs across the lores, and continues behind the eye. Where a stripe is present only above the lores, and does not continue behind the eye, it is called a supraloral stripe or simply supraloral. On most species which display a supercilium, it is paler than the adjacent feather tracts. The colour, shape or other features of the supercilium can be useful in bird identification. For example, the supercilium of the dusky warbler, an Old World warbler species, can be used to distinguish it from the very similar Radde's warbler. The dusky warbler's supercilium is sharply demarcated, whitish and narrow in front of the eye, becoming broader and more buffy towards the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buff (color)
Buff (latin ''bubalinus'') is a light brownish yellow, ochreous colour, typical of buff leather. Buff is a mixture of yellow ochre and white: two parts of white lead and one part of yellow ochre produces a good buff, or white lead may be tinted with French ochre alone. As an RYB quaternary colour, it is the colour produced by an equal mix of the tertiary colours citron and russet. Etymology The first recorded use of the word ''buff'' to describe a colour was in '' The London Gazette'' of 1686, describing a uniform to be "...a Red Coat with a Buff-colour'd lining". It referred to the colour of undyed buffalo leather, such as soldiers wore as some protection: an eyewitness to the death in the Battle of Edgehill (1642) of Sir Edmund Verney noted "he would neither put on arms rmouror buff coat the day of the battle". Such buff leather was suitable for ''buffing'' or serving as a ''buffer'' between polished objects. It is not clear which bovine "''buffalo''" referred t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Down Feather
The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Powder down is a specialized type of down found only in a few groups of birds. Down is a fine thermal insulator and padding, used in goods such as jackets, bedding ( duvets and featherbeds), pillows and sleeping bags. The discovery of feathers trapped in ancient amber suggests that some species of dinosaur may have possessed down-like feathers. Description and etymology The word ''down'' comes from the Old Norse word ''dúnn'', which had the same meaning as its modern equivalent. The down feather is considered to be the most "straightforward" of all feather types. It has a short or vestigial rachis (shaft), few barbs, and barbules that lack hooks. There are three types of down: natal down, body down and powder down. Natal down is the layer of down feathers that cover most birds at some point in their early development. Precocial nestlings a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Supercilium")
