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Mexican Duck (female)
The Mexican duck (''Anas diazi'') is a species of dabbling duck that breeds in Mexico and the southwestern United States. Distribution and habitat Most of the population is resident, but some northern birds bird migration, migrate south to Mexico in winter. The species also occurs widely, but in limited numbers, in Colorado in all seasons and there are photographs of birds referable to this taxon from Utah, Wyoming, Nebraska, and Montana. It is a bird of most wetlands, including ponds and rivers, and usually feeds by dabbling for plant food or grazing. It nests usually on a river bank, but not always particularly near water. Diet Mexican ducks are fond of the green shoots of Alfalfa, alfafa and feed at night on irrigated fields. Description Both sexes of this 51–56 cm length bird resemble a female mallard, but with a slightly darker body. The Mexican duck is mainly brown, with a blue speculum feathers, speculum edged with white, obvious in flight or at rest. The male has ... [...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] |
Allopatric
Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow. Various geographic changes can arise such as the movement of continents, and the formation of mountains, islands, bodies of water, or glaciers. Human activity such as agriculture or developments can also change the distribution of species populations. These factors can substantially alter a region's geography, resulting in the separation of a species population into isolated subpopulations. The vicariant populations then undergo genetic changes as they become subjected to different selective pressures, experience genetic drift, and accumulate different mutations in the separated populations' gene pools. The barriers prevent the exchange of genetic information between t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helm Identification Guides
The ''Helm Identification Guides'' are a series of books that identify groups of birds. The series include two types of guides, those that are: * Taxonomic, dealing with a particular family of birds on a worldwide scale—most early Helm Guides were this type, as well as many more-recent ones, although some later books deal with identification of such groups on a regional scale only (e.g., ''The Gulls Guide,'' which covers only species in Europe, Asia, and North America) * Geographic, including all bird species in an area (e.g., ''The Birds of the West Indies'') Early volumes were sometimes published under the Croom Helm or Christopher Helm imprints. In addition, a parallel set of guides, very similar in design, was published by Pica Press in the 1990s (marked ''Pica'' in the list below); Pica was later absorbed into A & C Black (now part of Bloomsbury Publishing Plc), and all guides are now marketed as a single series. Several of the books have won the British Birds ''Bird B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Ornithologists' Union
The American Ornithological Society (AOS) is an ornithological organization based in the United States. The society was formed in October 2016 by the merger of the American Ornithologists' Union (AOU) and the Cooper Ornithological Society. Its members are primarily professional ornithologists, although membership is open to anyone with an interest in birds. The society publishes the two scholarly journals, ''The Auk'' and '' The Condor'' as well as the ''AOS Checklist of North American Birds''. In 2013, the American Ornithologists' Union announced a close partnership with the Cooper Ornithological Society, including joint meetings, a centralized publishing office, and a refocusing of their respective journals to increase efficiency of research. In October 2016, the AOU announced that it was ceasing to operate as an independent union and was merging with the Cooper Ornithological Society to create the American Ornithological Society. History The American Ornithologists' Unio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Fish And Wildlife Service
The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with others to conserve, protect, and enhance fish, wildlife, plants and their habitats for the continuing benefit of the American people." Among the responsibilities of the USFWS are enforcing federal wildlife laws; protecting endangered species; managing migratory birds; restoring nationally significant fisheries; conserving and restoring wildlife habitats, such as wetlands; helping foreign governments in international conservation efforts; and distributing money to fish and wildlife agencies of U.S. states through the Wildlife Sport Fish and Restoration Program. The vast majority of fish and wildlife habitats are on U.S. state, state or private land not controlled by the United States government. Therefore, the USFWS works closely with private g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxonomy (biology)
In biology, taxonomy () is the scientific study of naming, defining ( circumscribing) and classifying groups of biological organisms based on shared characteristics. Organisms are grouped into taxa (singular: taxon) and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a more inclusive group of higher rank, thus creating a taxonomic hierarchy. The principal ranks in modern use are domain, kingdom, phylum (''division'' is sometimes used in botany in place of ''phylum''), class, order, family, genus, and species. The Swedish botanist Carl Linnaeus is regarded as the founder of the current system of taxonomy, as he developed a ranked system known as Linnaean taxonomy for categorizing organisms and binomial nomenclature for naming organisms. With advances in the theory, data and analytical technology of biological systematics, the Linnaean system has transformed into a system of modern biological classification intended to reflect the evolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Destruction Of Habitat
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby reducing biodiversity and species abundance. Habitat destruction is the leading cause of biodiversity loss. Fragmentation and loss of habitat have become one of the most important topics of research in ecology as they are major threats to the survival of endangered species. Activities such as harvesting natural resources, industrial production and urbanization are human contributions to habitat destruction. Pressure from agriculture is the principal human cause. Some others include mining, logging, trawling, and urban sprawl. Habitat destruction is currently considered the primary cause of species extinction worldwide. Environmental factors can contribute to habitat destruction more indirectly. Geological processes, climate change, introdu ... [...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] |
Mexican Duck (female)
The Mexican duck (''Anas diazi'') is a species of dabbling duck that breeds in Mexico and the southwestern United States. Distribution and habitat Most of the population is resident, but some northern birds bird migration, migrate south to Mexico in winter. The species also occurs widely, but in limited numbers, in Colorado in all seasons and there are photographs of birds referable to this taxon from Utah, Wyoming, Nebraska, and Montana. It is a bird of most wetlands, including ponds and rivers, and usually feeds by dabbling for plant food or grazing. It nests usually on a river bank, but not always particularly near water. Diet Mexican ducks are fond of the green shoots of Alfalfa, alfafa and feed at night on irrigated fields. Description Both sexes of this 51–56 cm length bird resemble a female mallard, but with a slightly darker body. The Mexican duck is mainly brown, with a blue speculum feathers, speculum edged with white, obvious in flight or at rest. The male has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Incompatibility
Genetic incompatibility describes the process by which mating yields offspring that are nonviable, prone to disease, or genetically defective in some way. In nature, animals can ill afford to devote costly resources for little or no reward, ergo, mating strategies have evolved to allow females to choose or otherwise determine mates which are more likely to result in viable offspring. Polyandry, for instance, when a female mates with two or more males during a period of sexual receptivity, reduces the chance that a singular mate is genetically incompatible. Exactly how females determine compatible genes prior to mating is not completely understood, but various mechanisms have been proposed, such as pheromones and male appearance and/or courtship behavior. It is also surmised that sexual selection can continue after copulation, the so called 'cryptic female choice', so named because it takes place within the body and cannot be directly observed. In this scenario, incompatible male s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selection (biology)
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which in his view is intentional, whereas natural selection is not. Variation exists within all populations of organisms. This occurs partly because random mutations arise in the genome of an individual organism, and their offspring can inherit such mutations. Throughout the lives of the individuals, their genomes interact with their environments to cause variations in traits. The environment of a genome includes the molecular biology in the cell, other cells, other individuals, populations, species, as well as the abiotic environment. Because individuals with certain variants of the trait tend to survive and reproduce more than individuals with o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Behavior
Behavior (American English) or behaviour (British English) is the range of actions and mannerisms made by individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as well as the inanimate physical environment. It is the computed response of the system or organism to various stimuli or inputs, whether internal or external, conscious or subconscious, overt or covert, and voluntary or involuntary. Taking a behavior informatics perspective, a behavior consists of actor, operation, interactions, and their properties. This can be represented as a behavior vector. Models Biology Although disagreement exists as to how to precisely define behavior in a biological context, one common interpretation based on a meta-analysis of scientific literature states that "behavior is the internally coordinated responses (actions or inactions) of whole living organisms (individuals or groups) to internal and/or external sti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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