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Eagle Looking Left
Eagle is the common name for many large birds of prey of the family Accipitridae. Eagles belong to several groups of genera, some of which are closely related. Most of the 68 species of eagle are from Eurasia and Africa. Outside this area, just 14 species can be found—2 in North America, 9 in Central and South America, and 3 in Australia. Eagles are not a natural group but denote essentially any kind of bird of prey large enough to hunt sizeable (about 50 cm long or more overall) vertebrates. Description Eagles are large, powerfully-built birds of prey, with heavy heads and beaks. Even the smallest eagles, such as the booted eagle (''Aquila pennata''), which is comparable in size to a common buzzard (''Buteo buteo'') or red-tailed hawk (''B. jamaicensis''), have relatively longer and more evenly broad wings, and more direct, faster flight – despite the reduced size of aerodynamic feathers. Most eagles are larger than any other raptors apart from some vultures. The smalle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golden Eagle
The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known bird of prey, birds of prey in the Northern Hemisphere. These birds are dark brown, with lighter golden-brown plumage on their napes. Immature eagles of this species typically have white on the tail and often have white markings on the wings. Golden eagles use their agility and speed combined with powerful feet and large, sharp talons to hunt a variety of prey, mainly hares, rabbits, and marmots and other ground squirrels. Golden eagles maintain home ranges or territories that may be as large as . They build large bird nest, nests in cliffs and other high places to which they may return for several breeding years. Most breeding activities take place in the spring; they are monogamous and may remain together for several years or possibly for life. Fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Nicobar Serpent Eagle
The Great Nicobar serpent eagle (''Spilornis klossi''), also known as the South Nicobar serpent eagle, is a species of bird of prey in the family Accipitridae. It is probably the smallest known eagle, with a weight of about , a wingspan of and a body length of about .Clark, W.S., G. M. Kirwan, and D. A. Christie (2020). ''Nicobar Serpent-Eagle (Spilornis klossi)'', version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. It is endemic to forest on the Indian island of Great Nicobar. It is threatened by habitat loss. All major authorities now treat the Great Nicobar serpent eagle as a species, but in the past it was sometimes considered a subspecies of ''S. minimus''. Today ''S. minimus'' is either considered a subspecies of the crested serpent eagle or a monotypic species from the central Nicobar Islands, the Central Nicobar serpent eagle. References * Ferguson-Lees & Chris ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bateleur
The bateleur (; ''Terathopius ecaudatus'') is a medium-sized eagle in the family Accipitridae. It is often considered a relative of the snake eagles and, like them, it is classified within the subfamily Circaetinae.Kemp, A. C., G. M. Kirwan, and D. A. Christie (2020). ''Bateleur (Terathopius ecaudatus)'', version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. It is the only member of the genus ''Terathopius'' and may be the origin of the "Zimbabwe Bird", the national emblem of Zimbabwe. Adult bateleurs are generally black in colour with a chestnut colour on the mantle as well as also on the rump and tail. Adults also have gray patches about the leading edges of the wings (extending to the secondaries in females) with bright red on their cere and their feet. Adults also show white greater coverts, contrasting with black remiges in males, gray patches on the underwing primarie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circaetus
''Circaetus'', the snake eagles, is a genus of medium-sized eagles in the bird of prey family Accipitridae. They are mainly resident African species, but the migratory short-toed snake eagle breeds from the Mediterranean basin into Russia, the Middle East and India, and winters in sub-Saharan Africa and east to Indonesia. Snake eagles are found in open habitats like cultivated plains arid savanna, but require trees in which to build a stick nest. The single egg is incubated mainly or entirely by the female. ''Circaetus'' eagles have a rounded head and broad wings. They prey on reptiles, mainly snakes, but also take lizards and occasionally small mammals. Taxonomy and species The genus ''Circaetus'' was introduced in 1816 by the French ornithologist Louis Jean Pierre Vieillot to accommodate a single species, the short-toed snake eagle, which is therefore considered the type species. The genus name is from the Ancient Greek Ancient Greek includes the forms of the Greek ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kleptoparasitism
Kleptoparasitism (etymologically, parasitism by theft) is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, which can mean when food is scarce or when victims are abundant. Many kleptoparasites are arthropods, especially bees and wasps, but including some true flies, dung beetles, bugs, and spiders. Cuckoo bees are specialized kleptoparasites which lay their eggs either on the pollen masses made by other bees, or on the insect hosts of parasitoid wasps. They are an instance of Emery's rule, which states that insect social parasites tend to be closely related to their hosts. The behavior occurs, too, in vertebrates including birds such as skuas, which persistently chase other seabirds until they disgorge their food, and carnivorous mammals such as spotted hyenas and lions. Other species opportunistically indulge in kleptoparasitism. Strategy Kleptoparasitism is a fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Bird
A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in freshwater ecosystems, although others make no distinction from seabirds that inhabit marine environments. Some water birds (e.g. wading birds) are more terrestrial while others (e.g. waterfowls) are more aquatic, and their adaptations will vary depending on their environment. These adaptations include webbed feet, beaks, and legs adapted to feed in the water, and the ability to dive from the surface or the air to catch prey in water. The term ''aquatic bird'' is sometimes also used in this context. A related term that has a narrower meaning is waterfowl. Some piscivorous birds of prey, such as ospreys and sea eagles, hunt aquatic prey but do not stay in water for long and lives predominantly over dry land, and are not considered water birds. The term waterbird is also used in the context of conservation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyophaga
A sea eagle or fish eagle (also called erne or ern, mostly in reference to the white-tailed eagle) is any of the birds of prey in the genus ''Haliaeetus'' in the bird of prey family Accipitridae. Taxonomy and evolution The genus ''Haliaeetus'' was introduced in 1809 by French naturalist Marie Jules César Savigny in his chapter on birds in the ''Description de l'Égypte''. The two fish eagles in the genus ''Ichthyophaga'' were found to lie within ''Haliaeetus'' in a genetic study in 2005, they were then moved accordingly. They are very similar to the tropical ''Haliaeetus'' species. A prehistoric (i.e. extinct before 1500) form from Maui in the Hawaiian Islands may represent a species or subspecies in this genus. The relationships to other genera in the family are less clear; they have long been considered closer to the genus ''Milvus'' (kites) than to the true eagles in the genus '' Aquila'' on the basis of their morphology and display behaviour;Brown, L. H, & Amadon, D. (1968) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haliaeetus
A sea eagle or fish eagle (also called erne or ern, mostly in reference to the white-tailed eagle) is any of the birds of prey in the genus ''Haliaeetus'' in the bird of prey family Accipitridae. Taxonomy and evolution The genus ''Haliaeetus'' was introduced in 1809 by French naturalist Marie Jules César Savigny in his chapter on birds in the ''Description de l'Égypte''. The two fish eagles in the genus ''Ichthyophaga'' were found to lie within ''Haliaeetus'' in a genetic study in 2005, they were then moved accordingly. They are very similar to the tropical ''Haliaeetus'' species. A prehistoric (i.e. extinct before 1500) form from Maui in the Hawaiian Islands may represent a species or subspecies in this genus. The relationships to other genera in the family are less clear; they have long been considered closer to the genus ''Milvus'' (kites) than to the true eagles in the genus '' Aquila'' on the basis of their morphology and display behaviour;Brown, L. H, & Amadon, D. (1968) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apex Predator
An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic levels. Food chains are often far shorter on land, usually limited to being secondary consumers – for example, wolves prey mostly upon large herbivores (primary consumers), which eat plants (primary producers). The apex predator concept is applied in wildlife management, conservation, and ecotourism. Apex predators have a long evolutionary history, dating at least to the Cambrian period when animals such as ''Anomalocaris'' dominated the seas. Humans have for many centuries interacted with apex predators including the wolf, birds of prey, and cormorants to hunt game animals, birds, and fish respectively. More recently, humans have started interacting with apex predators in new ways. These include interactions via ecotourism, such as with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American robin or Eurasian blackbird, or the elaborately woven hanging nest of the Montezuma oropendola or the village weaver—that is too restrictive a definition. For some species, a nest is simply a shallow depression made in sand; for others, it is the knot-hole left by a broken branch, a burrow dug into the ground, a chamber drilled into a tree, an enormous rotting pile of vegetation and earth, a shelf made of dried saliva or a mud dome with an entrance tunnel. The smallest bird nests are those of some hummingbirds, tiny cups which can be a mere across and high. At the other extreme, some nest mounds built by the dusky scrubfowl measure more than in diameter and stand nearly tall. The study of birds' nests is known as ''caliology''. Not all bird species bui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffraction
Diffraction is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a secondary source of the propagating wave. Italian scientist Francesco Maria Grimaldi coined the word ''diffraction'' and was the first to record accurate observations of the phenomenon in 1660. In classical physics, the diffraction phenomenon is described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets. The characteristic bending pattern is most pronounced when a wave from a coherent source (such as a laser) encounters a slit/aperture that is comparable in size to its wavelength, as shown in the inserted image. This is due to the addition, or interference, of different points on the wavefront (or, equivalently, each wavelet) that travel by paths of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Acuity
Visual acuity (VA) commonly refers to the clarity of vision, but technically rates an examinee's ability to recognize small details with precision. Visual acuity is dependent on optical and neural factors, i.e. (1) the sharpness of the retinal image within the eye, (2) the health and functioning of the retina, and (3) the sensitivity of the interpretative faculty of the brain. The most commonly referred visual acuity is the far acuity (e.g. 6/6 or 20/20 acuity), which describes the examinee's ability to recognize small details at a far distance, and is relevant to people with myopia; however, for people with hyperopia, the near acuity is used instead to describe the examinee's ability to recognize small details at a near distance. A common cause of low visual acuity is refractive error (ametropia), errors in how the light is refracted in the eyeball, and errors in how the retinal image is interpreted by the brain. The latter is the primary cause for low vision in people with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
