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Brood Reduction
Brood reduction occurs when the number of nestlings in a birds brood is reduced, usually because there is a limited amount of resources available. It can occur directly via infanticide, or indirectly via competition over resources between siblings. Avian parents often produce more offspring than they can care for, resulting in the death of some of the nestlings. Brood reduction was originally described by David Lack in his brood-reduction hypothesis to explain the existence of hatching asynchrony in many bird species. Hatching asynchrony occurs when the parents start incubating their eggs before all of them have been laid. If resources are limited, it benefits the parents to allow brood reduction, because it reduces the amount of work they must do and increases their chances of surviving and reproducing again in future years. Brood reduction has been observed in many avian species including seabirds such as black-legged kittiwakes, birds of prey such as Swainson's hawk and several e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infanticide (zoology)
In animals, infanticide involves the intentional killing of young offspring by a mature animal of the same species. Animal infanticide is studied in zoology, specifically in the field of ethology. Ovicide is the analogous destruction of eggs. The practice has been observed in many species throughout the animal kingdom, especially primates ( primate infanticide) but including microscopic rotifers, insects, fish, amphibians, birds and mammals. Infanticide can be practiced by both males and females. Infanticide caused by sexual conflict has the general theme of the killer (often male) becoming the new sexual partner of the victim's parent, which would otherwise be unavailable. This represents a gain in fitness by the killer, and a loss in fitness by the parents of the offspring killed. This is a type of evolutionary struggle between the two sexes, in which the victim sex may have counter-adaptations that reduce the success of this practice. It may also occur for other reasons, suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crowned Eagle
The crowned eagle, also known as the African crowned eagle or the crowned hawk-eagle (''Stephanoaetus coronatus''), is a large bird of prey found in sub-Saharan Africa; in Southern Africa it is restricted to eastern areas.Sinclair & Ryan (2003). ''Birds of Africa south of the Sahara''. Its preferred habitats are principally riparian woodlands and various forests. The crowned eagle is the only extant member of the genus ''Stephanoaetus''. A second species, the Malagasy crowned eagle (''Stephanoaetus mahery'') became extinct after humans settled on Madagascar.Goodman, Steven M. (1994). Proceedings of the Biological Society of Washington 107(3): 421–428 ISSN 0006-324''Description of a new species of subfossil eagle from Madagascar: ''Stephanoaetus'' (Aves: Falconiformes) From The Deposits Of Ampasambazimba''. At least 90 percent of the diet is mammalian; the usual prey taken by populations shows pronounced regional differences. Throughout its range the principal prey items are s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown-and-yellow Marshbird
The brown-and-yellow marshbird (''Pseudoleistes virescens'') is a species of bird in the family Icteridae. It is found in the Pampas and north to the Paraguayan border and Rio Grande do Sul, where its natural habitats are swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...s and pastureland. References External linksPhoto– oiseaux.net brown-and-yellow marshbird Birds of Argentina Birds of Uruguay brown-and-yellow marshbird Taxa named by Louis Jean Pierre Vieillot Taxonomy articles created by Polbot {{Icteridae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Screaming Cowbird
The screaming cowbird (''Molothrus rufoaxillaris'') is an obligate brood parasite belonging to the family Icteridae and is found in South America. It is also known commonly as the short billed cowbird.Fraga, R. M. (2011). Family Icteridae (New World Blackbirds). In Handbook of the Birds of the World, vol 16: Tanagers to New World Blackbirds (J. del Hoyo,. A. Elliot, and D. A. Christie, Editors). Lynx Edicions, Barcelona, Spain. pp. 684-807 Description The screaming cowbird has mildly iridescent black plumage; the lesser under-wing coverts are rufous. The female is slightly duller in colour than the male. The legs are black and the iris is reddish brown. Adult body length is 18–21 cm and mean adult weight is 58 g for males and 48 g for females.Davies, N. B. (2000). Cuckoos, Cowbirds and Other Cheats. Academic Press, London The call of the screaming cowbird was first described as "impetuous screaming notes"; however, a more useful description for field identificat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shiny Cowbird
The shiny cowbird (''Molothrus bonariensis'') is a passerine bird in the New World family Icteridae. It breeds in most of South America except for dense forests and areas of high altitude such as mountains. Since 1900 the shiny cowbird's range has shifted northward, and it was recorded in the Caribbean islands as well as the United States, where it is found breeding in southern Florida. It is a bird associated with open habitats, including disturbed land from agriculture and deforestation. Adults are sexually dimorphic. Males are all black with a purple-blue iridescence. The female is smaller, with dull brown plumage that is sometimes paler on the underparts. Females of the species can be distinguished from the female brown-headed cowbird by their longer, finer bills and flatter heads. The shiny cowbird's diet consists mainly of insects, other arthropods and seeds, and they have been recorded foraging for grains in cattle troughs. Like most other cowbirds, it is an obligate brood ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brood Parasite
Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own, usually using egg mimicry, with eggs that resemble the host's. The evolutionary strategy relieves the parasitic parents from the investment of rearing young. This benefit comes at the cost of provoking an evolutionary arms race between parasite and host as they coevolve: many hosts have developed strong defenses against brood parasitism, such as recognizing and ejecting parasitic eggs, or abandoning parasitized nests and starting over. It is less obvious why most hosts do care for parasite nestlings, given that for example cuckoo chicks differ markedly from host chicks in size and appearance. One explanation, the mafia hypothesis, proposes that parasitic adults retaliate by destroying host nests where rejection has occurred; there is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Savannah Sparrow, Passerculus Sandwichensis, Nestlings Baby Birds And Eggs With Much Larger Brown-headed Cowbird, Molothrus Ater Nestling AB Canada (2)
A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of grasses. According to '' Britannica'', there exists four savanna forms; ''savanna woodland'' where trees and shrubs form a light canopy, ''tree savanna'' with scattered trees and shrubs, ''shrub savanna'' with distributed shrubs, and ''grass savanna'' where trees and shrubs are mostly nonexistent.Smith, Jeremy M.B.. "savanna". Encyclopedia Britannica, 5 Sep. 2016, https://www.britannica.com/science/savanna/Environment. Accessed 17 September 2022. Savannas maintain an open canopy despite a high tree density. It is often believed that savannas feature widely spaced, scattered trees. However, in many savannas, tree densities are higher and trees are more regularly spaced than in for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greater Spotted Eagle
The greater spotted eagle (''Clanga clanga''), occasionally called the spotted eagle, is a large bird of prey. Like all typical eagles, it belongs to the family Accipitridae. Its feathered legs indicate it is a member of the subfamily Aquilinae, also known as the "booted eagles".Helbig, A. J., Kocum, A., Seibold, I., & Braun, M. J. (2005). ''A multi-gene phylogeny of aquiline eagles (Aves: Accipitriformes) reveals extensive paraphyly at the genus level''. Molecular phylogenetics and evolution, 35(1), 147-164. This species was once thought to be included in the genus '' Aquila'' but now belongs to a distinct genus, '' Clanga'', along with the other two species of spotted eagles.Helbig, A. J., Seibold, I., Kocum, A., Liebers, D., Irwin, J., Bergmanis, U., Meyburg, B.-U., Scheller, W., Stubbe, M. & Bensch, S. (2005). ''Genetic differentiation and hybridization between greater and lesser spotted eagles (Accipitriformes: Aquila clanga, A. pomarina)''. The Journal of Ornithology, 146(3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golden Eagle Chick, Circa 1938 (6478691399)
Golden means made of, or relating to gold. Golden may also refer to: Places United Kingdom *Golden, in the parish of Probus, Cornwall *Golden Cap, Dorset *Golden Square, Soho, London *Golden Valley, a valley on the River Frome in Gloucestershire *Golden Valley, Herefordshire United States *Golden, Colorado, a town West of Denver, county seat of Jefferson County *Golden, Idaho, an unincorporated community *Golden, Illinois, a village *Golden Township, Michigan *Golden, Mississippi, a village *Golden City, Missouri, a city *Golden, Missouri, an unincorporated community *Golden, Nebraska, ghost town in Burt County *Golden Township, Holt County, Nebraska *Golden, New Mexico, a sparsely populated ghost town *Golden, Oregon, an abandoned mining town *Golden, Texas, an unincorporated community *Golden, Utah, a ghost town *Golden, Marshall County, West Virginia, an unincorporated community Elsewhere *Golden, County Tipperary, Ireland, a village on the River Suir *Golden Vale, Munster, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Lack
David Lambert Lack FRS (16 July 1910 – 12 March 1973) was a British evolutionary biologist who made contributions to ornithology, ecology, and ethology. His 1947 book, ''Darwin's Finches'', on the finches of the Galapagos Islands was a landmark work as were his other popular science books on ''Life of the Robin'' and ''Swifts in a Tower''. He developed what is now known as Lack's Principle which explained the evolution of avian clutch sizes in terms of individual selection as opposed to the competing contemporary idea that they had evolved for the benefit of species (also known as group selection). His pioneering life-history studies of the living bird helped in changing the nature of ornithology from what was then a collection-oriented field. He was a longtime director of the Edward Grey Institute of Field Ornithology at the University of Oxford. Education and early life Lack was born in London, the oldest of four children of Harry Lambert Lack MD FRCS, who later became Pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Stork
The white stork (''Ciconia ciconia'') is a large bird in the stork family, Ciconiidae. Its plumage is mainly white, with black on the bird's wings. Adults have long red legs and long pointed red beaks, and measure on average from beak tip to end of tail, with a wingspan. The two subspecies, which differ slightly in size, breed in Europe (north to Finland), northwestern Africa, southwestern Asia (east to southern Kazakhstan) and southern Africa. The white stork is a long-distance migrant, wintering in Africa from tropical Sub-Saharan Africa to as far south as South Africa, or on the Indian subcontinent. When migrating between Europe and Africa, it avoids crossing the Mediterranean Sea and detours via the Levant in the east or the Strait of Gibraltar in the west, because the air thermals on which it depends for soaring do not form over water. A carnivore, the white stork eats a wide range of animal prey, including insects, fish, amphibians, reptiles, small mammals and small bir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siblicide
Siblicide (attributed by behavioural ecologist Doug Mock to Barbara M. Braun) is the killing of an infant individual by its close relatives (full or half siblings). It may occur directly between siblings or be mediated by the parents, and is driven by the direct fitness benefits to the perpetrator and sometimes its parents. Siblicide has mainly, but not only, been observed in birds. (The word is also used as a unifying term for fratricide and sororicide in the human species; unlike these more specific terms, it leaves the sex of the victim unspecified.) Siblicidal behavior can be either obligate or facultative. Obligate siblicide is when a sibling almost always ends up being killed. Facultative siblicide means that siblicide may or may not occur, based on environmental conditions. In birds, obligate siblicidal behavior results in the older chick killing the other chick(s). In facultative siblicidal animals, fighting is frequent, but does not always lead to death of a sibling; th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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