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Avian Clutch Size
Clutch size refers to the number of eggs laid in a single brood by a nesting pair of birds. The numbers laid by a particular species in a given location are usually well defined by evolutionary trade-offs with many factors involved, including resource availability and energetic constraints. Several patterns of variation have been noted and the relationship between latitude and clutch size has been a topic of interest in avian reproduction and evolution. David Lack and R.E. Moreau were among the first to investigate the effect of latitude on the number of eggs per nest. Since Lack's first paper in the mid-1940s there has been extensive research on the pattern of increasing clutch size with increasing latitude. The proximate and ultimate causes for this pattern have been a subject of intense debate involving the development of ideas on group, individual, and gene-centric views of selection. Food limitation and nest predation hypotheses David Lack observed a direct relationship b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larus Marinus Eggs
''Larus'' is a large genus of gulls with worldwide distribution (by far the greatest species diversity is in the Northern Hemisphere). Many of its species are abundant and well-known birds in their ranges. Until about 2005–2007, most gulls were placed in this genus, but this arrangement is now known to be polyphyletic, leading to the resurrection of the genera ''Ichthyaetus'', ''Chroicocephalus'', ''Leucophaeus'', and '' Hydrocoloeus'' (this last had been recognized more often than the other genera) for several species traditionally included in ''Larus''. They are in general medium to large birds, typically grey or white, often with black markings on their heads or wings. They have stout, longish bills and webbed feet. The taxonomy of the large gulls in the herring and lesser black-backed complex is very complicated, with different authorities recognising between two and eight species. Taxonomy The genus ''Larus'' was introduced in 1758 by the Swedish naturalist Carl Li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glareolidae
Glareolidae is a family of birds in the wader suborder Charadrii. It contains two distinct groups, the pratincoles and the coursers. The atypical Egyptian plover (''Pluvianus aegyptius''), traditionally placed in this family, is now known to be only distantly related. The family contains 17 species in 4 genera. Description The feature that defines the family from the rest of the order is the bill, which is arched and has the nostrils at the base. The pratincoles have short legs, long pointed wings and long forked tails. They have a buoyant flight that allows them the unusual (for the order) hunting technique of taking their insect prey on the wing like swallows. The wings also allow for long migrations in some species. The coursers have long legs, which are used to run (giving the group its name). The wings are shorter and have a more sustained flight than that of the pratincoles. Distribution and habitat The pratincoles and coursers have an Old World distribution, occu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resident Bird
Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by the availability of food. It occurs mainly in the northern hemisphere, where birds are funneled onto specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea. Migration of species such as storks, turtle doves, and swallows was recorded as many as 3,000 years ago by Ancient Greek authors, including Homer and Aristotle, and in the Book of Job. More recently, Johannes Leche began recording dates of arrivals of spring migrants in Finland in 1749, and modern scientific studies have used techniques including bird ringing and satellite tracking to trace migrants. Threats to migratory birds have grown with habitat destruction, especially of stopover and wintering sites, as we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Migration
Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by the availability of food. It occurs mainly in the northern hemisphere, where birds are funneled onto specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea. Migration of species such as storks, turtle doves, and swallows was recorded as many as 3,000 years ago by Ancient Greek authors, including Homer and Aristotle, and in the Book of Job. More recently, Johannes Leche began recording dates of arrivals of spring migrants in Finland in 1749, and modern scientific studies have used techniques including bird ringing and satellite tracking to trace migrants. Threats to migratory birds have grown with habitat destruction, especially of stopover and wintering sites, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Competition (biology)
Competition is an interaction between organisms or species in which both require a resource that is in limited supply (such as food, water, or territory). Competition lowers the fitness of both organisms involved since the presence of one of the organisms always reduces the amount of the resource available to the other. In the study of community ecology, competition within and between members of a species is an important biological interaction. Competition is one of many interacting biotic and abiotic factors that affect community structure, species diversity, and population dynamics (shifts in a population over time). There are three major mechanisms of competition: interference, exploitation, and apparent competition (in order from most direct to least direct). Interference and exploitation competition can be classed as "real" forms of competition, while apparent competition is not, as organisms do not share a resource, but instead share a predator. Competition among me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breeding Pair
Breeding pair is a pair of animals which cooperate over time to produce offspring with some form of a bond between the individuals.Gaston, A. J.The evolution of group territorial behavior and cooperative breeding" The American Naturalist 112.988 (1978): 1091-1100. For example, many birds mate for a breeding season or sometimes for life. They may share some or all of the tasks involved: for example, a breeding pair of birds may split building a nest, incubating the eggs and feeding and protecting the young. The term is not generally used when a male has a harem of females, such as with mountain gorillas. True breeding pairs are usually found only in vertebrates, but there are notable exceptions, such as the Lord Howe Island stick insect. True breeding pairs are rare in amphibians or reptiles, although the Australian Shingleback is one exception with long-term pair-bonds. Some fish form short term pairs and the French angelfish is thought to pair-bond over a long term. True b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colaptes Auratus
The northern flicker or common flicker (''Colaptes auratus'') is a medium-sized bird of the woodpecker family. It is native to most of North America, parts of Central America, Cuba, and the Cayman Islands, and is one of the few woodpecker species that migrate. Over 100 common names for the northern flicker are known, including yellowhammer (not to be confused with the Eurasian yellowhammer (''Emberiza citrinella'')), clape, gaffer woodpecker, harry-wicket , heigh-ho, wake-up, walk-up, wick-up, yarrup, and gawker bird. Many of these names derive from attempts to imitate some of its calls. It is the state bird of Alabama (known by its colloquial name "yellowhammer.") Taxonomy The English naturalist Mark Catesby described and illustrated the northern flicker in his book ''The Natural History of Carolina, Florida and the Bahama Islands'' which was published between 1729 and 1732. Catesby used the English name "Gold-winged Wood-pecker" and the Latin ''Picus major alis aureis''. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limiting Resource
A limiting factor is a variable of a system that causes a noticeable change in output or another measure of a type of system. The limiting factor is in a pyramid shape of organisms going up from the producers to consumers and so on. A factor not limiting over a certain domain of starting conditions may yet be limiting over another domain of starting conditions, including that of the factor. Overview The identification of a factor as limiting is possible only in distinction to one or more other factors that are non-limiting. Disciplines differ in their use of the term as to whether they allow the simultaneous existence of more than one limiting factor which (may then be called "co-limiting"), but they all require the existence of at least one non-limiting factor when the terms are used. There are several different possible scenarios of limitation when more than one factor is present. The first scenario, called ''single limitation'' occurs when only one factor, the one with maximum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Flicker Pair
Northern may refer to the following: Geography * North, a point in direction * Northern Europe, the northern part or region of Europe * Northern Highland, a region of Wisconsin, United States * Northern Province, Sri Lanka * Northern Range, a range of hills in Trinidad Schools * Northern Collegiate Institute and Vocational School (NCIVS), a school in Sarnia, Canada * Northern Secondary School, Toronto, Canada * Northern Secondary School (Sturgeon Falls), Ontario, Canada * Northern University (other), various institutions * Northern Guilford High School, a public high school in Greensboro, North Carolina Companies * Arriva Rail North, a former train operating company in northern England * Northern Bank, commercial bank in Northern Ireland * Northern Foods, based in Leeds, England * Northern Pictures, an Australian-based television production company * Northern Rail, a former train operating company in northern England * Northern Railway of Canada, a defunct railway in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subtropical
The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north and south. The horse latitudes lie within this range. Subtropical climates are often characterized by hot summers and mild winters with infrequent frost. Most subtropical climates fall into two basic types: humid subtropical ( Koppen climate Cfa), where rainfall is often concentrated in the warmest months, for example Southeast China and the Southeastern United States, and dry summer or Mediterranean climate ( Koppen climate Csa/Csb), where seasonal rainfall is concentrated in the cooler months, such as the Mediterranean Basin or Southern California. Subtropical climates can also occur at high elevations within the tropics, such as in the southern end of the Mexican Plateau and in Da Lat of the Vietnamese Central Highlands. The six c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Study
Field research, field studies, or fieldwork is the collection of raw data outside a laboratory, library, or workplace setting. The approaches and methods used in field research vary across disciplines. For example, biologists who conduct field research may simply observe animals interacting with their environments, whereas social scientists conducting field research may interview or observe people in their natural environments to learn their languages, folklore, and social structures. Field research involves a range of well-defined, although variable, methods: informal interviews, direct observation, participation in the life of the group, collective discussions, analyses of personal documents produced within the group, self-analysis, results from activities undertaken off- or on-line, and life-histories. Although the method generally is characterized as qualitative research, it may (and often does) include quantitative dimensions. History Field research has a long history ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breeding Season
Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the optimization of survival of young due to factors such as ambient temperature, food and water availability, and changes in the predation behaviors of other species. Related sexual interest and behaviors are expressed and accepted only during this period. Female seasonal breeders will have one or more estrus cycles only when she is "in season" or fertile and receptive to mating. At other times of the year, they will be anestrus, or have a dearth of their sexual cycle. Unlike reproductive cyclicity, seasonality is described in both males and females. Male seasonal breeders may exhibit changes in testosterone levels, testes weight, and fertility depending on the time of year. Seasonal breeders are distinct from opportunistic breeders, that mate whenever the conditions of their environment become favorable, and continuous breeders that mate year-ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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