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Hawk-eagle
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 smallest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martial Eagle
The martial eagle (''Polemaetus bellicosus'') is a large eagle native to sub-Saharan Africa.Ferguson-Lees & Christie, ''Raptors of the World''. Houghton Mifflin Company (2001), . It is the only member of the genus ''Polemaetus''. A species of the booted eagle subfamily (Aquilinae), it has feathering over its tarsus. One of the largest and most powerful species of booted eagle, it is a fairly opportunistic predator that varies its prey selection between mammals, birds and reptiles. It is one of few eagle species known to hunt primarily from a high soar, by stooping on its quarry.Steyn, P. (1983). ''Birds of prey of southern Africa: Their identification and life histories''. Croom Helm, Beckenham (UK). 1983. An inhabitant of wooded belts of otherwise open savanna, this species has shown a precipitous decline in the last few centuries due to a variety of factors. The martial eagle is one of the most persecuted bird species in the world. Due to its habit of taking livestock and re ... [...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] |
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] |
Black Eagle
The black eagle (''Ictinaetus malaiensis'') is a bird of prey. Like all eagles, it is in the family Accipitridae, and is the only member of the genus ''Ictinaetus''. They soar over forests in the hilly regions of tropical and subtropical South and Southeast Asia, as well as southeastern China. They hunt mammals and birds, particularly at their nests. They are easily identified by their widely splayed and long primary "fingers", the characteristic silhouette, slow flight and yellow ceres and legs that contrast with their dark feathers. Taxonomy and systematics The species name is spelt ''malayensis'' in most publications but the original spelling used by Temminck in his description uses the spelling ''malaiensis'' according to a 2011 finding of some of the original covers of the part publications leading to taxonomists applying the principle of priority and rejecting any later spelling emendations. Subspecies *''Ictinaetus malaiensis malaiensis'' - Myanmar to S China, SE Asia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Booted Eagle
The booted eagle (''Hieraaetus pennatus'', also classified as ''Aquila pennata'') is a medium-sized mostly migratory bird of prey with a wide distribution in the Palearctic and southern Asia, wintering in the tropics of Africa and Asia, with a small, disjunct breeding population in south-western Africa. Like all eagles, it belongs to the family ''Accipitridae''. Taxonomy The booted eagle was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's ''Systema Naturae''. He placed it with the eagle, falcons and relatives in the genus '' Falco'' and coined the binomial name ''Falco pennatus''. Gmelin based his description on "Le Faucon Patu" or "Falco pedibus pennatis" that had been described and illustrated in 1760 by the French zoologist Mathurin Jacques Brisson. Brisson had examined a specimen in the collection of Madame de Bandeville who was also known as Marie Anne Catherine Bigot de Graveron (1709-1787 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accipitridae
The Accipitridae is one of the three families within the order Accipitriformes, and is a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-sized mammals, with a number feeding on carrion and a few feeding on fruit. The Accipitridae have a cosmopolitan distribution, being found on all the world's continents (except Antarctica) and a number of oceanic island groups. Some species are migratory. The family contains 255 species which are divided into 70 genera. Many well-known birds such as hawks, eagles, kites, harriers and Old World vultures are included in this group. The osprey is usually placed in a separate family (Pandionidae), as is the secretary bird (Sagittariidae), and the New World vultures are also usually now regarded as a separate family or order. Karyotype data indicate the accipitrids analysed are indeed a distinct monophyletic group. Systematics and phylogeny ... [...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] |
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] |
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] |
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] |
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] |
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] |
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