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Yellow-billed Duck
The yellow-billed duck (''Anas undulata'') is a 51–58 cm long dabbling duck which is an abundant resident breeder in southern and eastern Africa. This duck is not migratory, but wanders in the dry season to find suitable waters. It is highly gregarious outside the breeding season and forms large flocks. Description These are mallard-sized mainly grey ducks with a darker head and bright yellow bill. The wings are whitish below, and from above show a white-bordered green speculum. Sexes are similar, and juveniles are slightly duller than adults. The north-eastern race is darker and has a brighter bill and blue speculum. It is a bird of freshwater habitats in fairly open country and feeds by dabbling for plant food mainly in the evening or at night. It nests on the ground in dense vegetation near water. Rarely, it is found in suburban areas, in close proximity to golf courses, parks and lakes or dams. The clutch numbers between six and twelve eggs. The male has a teal- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Frédéric Dubois
Charles Frédéric Dubois (28 May 1804 – 12 November 1867) was a Belgian naturalist. He was the author of ''Planches colorées des oiseaux de l’Europe'' ("Color plates of the birds of Europe") and ''Catalogue systématique des Lépidoptères de la Belgique'' ("Systematic catalog of the Lepidoptera of Belgium"), which was completed by his son, Alphonse Joseph Charles Dubois (1839–1921), after his death. The following quote has been widely attributed to Charles Dubois, as on thFavorite Quotesblog: "The important thing is this: to be able at any moment to sacrifice what we are for what we could become." However, its correct attribution appears to be to Charles Du Bos (1882-1939), the French critic of French and English literature. The quote comes from his book ''Approximations'' (1922): ''"...premier tressaillement vital; surtout il s'agit à tout moment de sacrifier ce que nous sommes à ce que nous pouvons devenir."'' Dubois is commemorated in the scientific name of a spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nominate Subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species have subspecies, but for those that do there must be at least two. Subspecies is abbreviated subsp. or ssp. and the singular and plural forms are the same ("the subspecies is" or "the subspecies are"). In zoology, under the International Code of Zoological Nomenclature, the subspecies is the only taxonomic rank below that of species that can receive a name. In botany and mycology, under the International Code of Nomenclature for algae, fungi, and plants, other infraspecific ranks, such as variety, may be named. In bacteriology and virology, under standard bacterial nomenclature and virus nomenclature, there are recommendations but not strict requirements for recognizing other important infraspecific ranks. A taxonomist decides whether ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birds Of Sub-Saharan Africa
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] |
Anas
''Anas'' is a genus of dabbling ducks. It includes the pintails, most teals, and the mallard and its close relatives. It formerly included additional species but following the publication of a molecular phylogenetic study in 2009 the genus was split into four separate genera. The genus now contains 31 living species. The name ''Anas'' is the Latin for "duck". Systematics The genus ''Anas'' was introduced by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his '' Systema Naturae''. ''Anas'' is the Latin word for a duck. The genus formerly included additional species. In 2009 a large molecular phylogentic study was published that compared mitochondrial DNA sequences from ducks, geese and swans in the family Anatidae. The results confirmed some of the conclusions of earlier smaller studies and indicated that the genus as then defined was non-monophyletic. Based on the results of this study, ''Anas'' was split into four proposed monophyletic genera with five ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Introgression
Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Introgression is a long-term process, even when artificial; it may take many hybrid generations before significant backcrossing occurs. This process is distinct from most forms of gene flow in that it occurs between two populations of different species, rather than two populations of the same species. Introgression also differs from simple hybridization. Simple hybridization results in a relatively even mixture; gene and allele frequencies in the first generation will be a uniform mix of two parental species, such as that observed in mules. Introgression, on the other hand, results in a complex, highly variable mixture of genes, and may only involve a minimal percentage of the donor genome. Definition Introgression or introgressive hybri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foraging
Foraging is searching for wild food resources. It affects an animal's Fitness (biology), fitness because it plays an important role in an animal's ability to survive and reproduce. Optimal foraging theory, Foraging theory is a branch of behavioral ecology that studies the foraging behavior of animals in response to the environment where the animal lives. Behavioral ecologists use economic models and categories to understand foraging; many of these models are a type of optimal model. Thus foraging theory is discussed in terms of optimizing a payoff from a foraging decision. The payoff for many of these models is the amount of energy an animal receives per unit time, more specifically, the highest ratio of energetic gain to cost while foraging. Foraging theory predicts that the decisions that maximize energy per unit time and thus deliver the highest payoff will be selected for and persist. Key words used to describe foraging behavior include ''resources'', the elements necessary fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moulting
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer layer or covering), either at specific times of the year, or at specific points in its life cycle. In medieval times it was also known as "mewing" (from the French verb "muer", to moult), a term that lives on in the name of Britain's Royal Mews where the King's hawks used to be kept during moulting time before becoming horse stables after Tudor times. Moulting can involve shedding the Epidermis (skin), epidermis (skin), pelage (hair, feathers, fur, wool), or other external layer. In some groups, other body parts may be shed, for example, the entire exoskeleton in arthropods, including the wings in some insects. Examples In birds In birds, moulting is the periodic replacement of feathers by shedding old feathers while producing new o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plumage
Plumage ( "feather") is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can be different colour morphs. The placement of feathers on a bird is not haphazard, but rather emerge in organized, overlapping rows and groups, and these are known by standardized names. Most birds moult twice a year, resulting in a breeding or ''nuptial plumage'' and a ''basic plumage''. Many ducks and some other species such as the red junglefowl have males wearing a bright nuptial plumage while breeding and a drab ''eclipse plumage'' for some months afterward. The painted bunting's juveniles have two inserted moults in their first autumn, each yielding plumage like an adult female. The first starts a few days after fledging replacing the ''juvenile plumage'' with an ''auxiliary formative plumage''; the second a month or so l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Courtship Display
A courtship display is a set of display behaviors in which an animal, usually a male, attempts to attract a mate; the mate exercises choice, so sexual selection acts on the display. These behaviors often include ritualized movement ("dances"), vocalizations, mechanical sound production, or displays of beauty, strength, or agonistic ability. Male display In some species, males will perform ritualized movements to attract females. The male six-plumed bird-of-paradise ( ''Parotia lawesii'') exemplifies male courtship display with its ritualized "ballerina dance" and unique occipital and breast feathers that serve to stimulate the female visual system. In ''Drosophila subobscura,'' male courtship display is seen through the male's intricate wing scissoring patterns and rapid sidestepping. These stimulations, along with many other factors, result in subsequent copulation or rejection. In other species, males may exhibit courtship displays that serve as both visual and auditory st ... [...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 tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AEWA
The Agreement on the Conservation of African-Eurasian Migratory Waterbirds, or African-Eurasian Waterbird Agreement (AEWA) is an independent international treaty developed under the auspices of the United Nations Environment Programme's Convention on Migratory Species. It was founded to coordinate efforts to conserve bird species migrating between European and African nations, and its current scope stretches from the Arctic to South Africa, encompassing the Canadian archipelago and the Middle East as well as Europe and Africa. The agreement focuses on bird species that depend on wetlands for at least part of their lifecycle and cross international borders in their migration patterns. It currently covers 254 species. Parties Meetings The Parties meet every few years. So far there have been seven meetings: * 7–9 November 1999 in Cape Town, South Africa * 25–27 September 2002 in Bonn, Germany * 23–27 October 2005 in Dakar, Senegal * 15–19 September 2008 in Antananarivo, M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward Blyth
Edward Blyth (23 December 1810 – 27 December 1873) was an English zoologist who worked for most of his life in India as a curator of zoology at the museum of the Asiatic Society of India in Calcutta. Blyth was born in London in 1810. In 1841 he travelled to India to become the curator of the museum of the Royal Asiatic Society of Bengal. He set about updating the museum's catalogues, publishing a ''Catalogue of the Birds of the Asiatic Society'' in 1849. He was prevented from doing much fieldwork himself, but received and described bird specimens from A.O. Hume, Samuel Tickell, Robert Swinhoe and others. He remained as curator until 1862, when ill-health forced his return to England. His ''Natural History of the Cranes'' was published posthumously in 1881. Avian species bearing his name include Blyth's hornbill, Blyth's leaf warbler, Blyth's hawk-eagle, Blyth's olive bulbul, Blyth's parakeet, Blyth's frogmouth, Blyth's reed warbler, Blyth's rosefinch, Blyth's shrike-babbl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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