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Accipitrinae
The Accipitrinae are the subfamily of the Accipitridae often known as the "true" hawks, including all members of ''Accipiter'' and the closely related genera ''Microspizias'', ''Erythrotriorchis'', and '' Megatriorchis''. The large and widespread genus ''Accipiter'' includes goshawks, sparrowhawks, the sharp-shinned hawk and others. They are primarily woodland birds that hunt by sudden dashes from a concealed perch, with long tails, broad wings and high visual acuity facilitating this lifestyle. In light of recent genetic research, the kites of the traditional subfamily Milvinae may also belong to this group. Hawks, including the accipitrines, are believed to have vision several times sharper than humans, in part because of the great number of photoreceptor cells in their retinas (up to 1,000,000 per square mm, against 200,000 for humans), a very high number of nerves connecting the receptors to the brain, and an indented fovea, which magnifies the central portion of the visual ... [...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] |
Megatriorchis
Doria's goshawk or Doria's hawk, (''Megatriorchis doriae'') is a raptor, the only member of the genus ''Megatriorchis''. Description At up to 69 cm long, it is among the biggest hawks in the broad sense. It is greyish-brown with a black-barred crown and upperparts, whitish underparts, a black streak behind the eye, dark brown irises, a blackish bill and greenish-yellow legs. The sexes are similar. The female is slightly larger than the male. Habitat and distribution Doria's goshawk is endemic to lowland rainforests of New Guinea and Batanta Island. Its diet consists mainly of birds, including the lesser bird of paradise, and other small animals. Conservation Due to ongoing habitat loss, Doria's goshawk is evaluated as Near Threatened on the IUCN Red List of Threatened Species. It is listed on Appendix II of CITES. Etymology In the genus name, "Mega-" is from the Greek word for "big". "Triorchis" was Greek for a kind of hawk thought to have three testicles — see '' Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accipiter
''Accipiter'' is a genus of Bird of prey, birds of prey in the family Accipitridae. With 51 recognized species it is the most diverse genus in its family. Most species are called goshawks or sparrowhawks, although almost all New World species (excepting the northern goshawk) are simply known as hawks. They can be anatomically distinguished from their relatives by the lack of a coracoid, procoracoid foramen. Two small and aberrant species usually placed here do possess a large procoracoid foramen and are also distinct as regards DNA sequence. They may warrant separation in the old genus ''Hieraspiza''.Olson (2006) Extant accipiters range in size from the little sparrowhawk (''A. minullus''), in which the smallest males measure long, span across the wings and weigh , to the northern goshawk (''A. gentilis''), in which the largest females measure long, span across the wings, and weigh . These birds are slender with short, broad, rounded wings and a long tail which helps them mane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microspizias
''Microspizias'' is a genus of bird of prey in the family Accipitridae. It contains the following species: * Tiny hawk (''Microspizias superciliosus'') * Semicollared hawk (''Microspizias collaris'') Both species were formerly classified in the genus ''Accipiter'', but a 2021 study found them to be strongly phylogenetically distinct, and thus described a new genus (''Microspizias'') for them. This was also followed by the International Ornithological Congress. Etymology ''Microspizias'' derives from the Greek word ''micros'' ("small") and ''spizias'' ("hawk"), literally translating to "small hawk". Taxonomy Phylogenetic evidence indicates that ''Microspizias'' is the sister genus to the lizard buzzard (''Kaupifalco monogrammicus'') of Africa and falls outside the Accipitrinae The Accipitrinae are the subfamily of the Accipitridae often known as the "true" hawks, including all members of '' Accipiter'' and the closely related genera ''Microspizias'', '' Erythrotrior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Besra
The besra (''Accipiter virgatus''), also called the besra sparrowhawk, is a bird of prey in the family Accipitridae. The besra is a widespread resident breeder in dense forests throughout southern Asia, ranging from the Indian subcontinent eastwards across Southeast Asia and into East Asia. It nests in trees, building a new nest each year. It lays 2 to 5 eggs. This bird is a medium-sized raptor (29 to 36 cm) with short broad wings and a long tail, both adaptations to fast maneuvering through dense vegetation. The normal flight of this species is a characteristic "flap–flap–glide". This species is like a darker version of the widespread shikra with darker upperparts, strongly barred underwing, broader gular stripe and thin long legs and toes. The adult male besra has dark blue-grey upperparts, and is white, barred reddish brown below. The larger female is browner above than the male. The juvenile is dark brown above and white, barred with brown below. In all plu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a vertebrate's body. In a human, the cerebral cortex contains approximately 14–16 billion neurons, and the estimated number of neurons in the cerebellum is 55–70 billion. Each neuron is connected by synapses to several thousand other neurons. These neurons typically communicate with one another by means of long fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells. Physiologically, brains exert centralized control over a body's other organs. They act on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. This centralized control allows rapid and coordinated respon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fovea Centralis
The fovea centralis is a small, central pit composed of closely packed cones in the eye. It is located in the center of the macula lutea of the retina. The fovea is responsible for sharp central vision (also called foveal vision), which is necessary in humans for activities for which visual detail is of primary importance, such as reading and driving. The fovea is surrounded by the ''parafovea'' belt and the ''perifovea'' outer region. The parafovea is the intermediate belt, where the ganglion cell layer is composed of more than five layers of cells, as well as the highest density of cones; the perifovea is the outermost region where the ganglion cell layer contains two to four layers of cells, and is where visual acuity is below the optimum. The perifovea contains an even more diminished density of cones, having 12 per 100 micrometres versus 50 per 100 micrometres in the most central fovea. That, in turn, is surrounded by a larger peripheral area, which delivers highly compres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Field
The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments". Or simply, visual field can be defined as the entire area that can be seen when an eye is fixed straight at a point. The equivalent concept for optical instruments and image sensors is the field of view (FOV). In optometry, ophthalmology, and neurology, a visual field test is used to determine whether the visual field is affected by diseases that cause local scotoma or a more extensive loss of vision or a reduction in sensitivity (increase in threshold). Normal limits The normal (monocular) human visual field extends to approximately 60 degrees nasally (toward the nose, or inward) from the vertical meridian in each eye, to 107 degrees temporally (away from the nose, or outwards) from the vertical meridian, and approximately 70 degrees above and 80 below the horizontal meridian. The binocular visual field is the superimposition of the two monocular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
African Goshawk
The African goshawk (''Accipiter tachiro'') is an African species of bird of prey in the genus ''Accipiter'' which is the type genus of the family Accipitridae. Description The African goshawk is a medium-sized to large ''Accipiter'' which is mainly grey and rufous with the typical broad-winged and long-tailed shape of its genus. The adult has grey upperparts which tend to be darker in males than in females, the underparts are whitish marked with rufous barring which is more pronounced in males. The underwing is pale rufous, fading to white on some birds and the flight feathers and tail vary from sooty brown to grey with faint grey bars above, white with grey bars below. The bill is black, the cere is greenish-grey, the eyes are yellow, and the legs and feet are yellow. Juveniles are brown above with whitish unterparts and flanks which are boldly blotched with brown. Females weigh , while the smaller males weigh . The wingspan is 1.7 times the bird's total length and in males an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sharp-shinned Hawk
The sharp-shinned hawk (''Accipiter striatus'') is a small hawk, with males being the smallest hawks in the United States and Canada, but with the species averaging larger than some Neotropical realm, Neotropical species, such as the tiny hawk. The Taxonomy (biology), taxonomy is far from resolved, with some authorities considering the southern taxon, taxa to represent three separate species: white-breasted hawk (''A. chionogaster''), plain-breasted hawk (''A. ventralis''), and rufous-thighed hawk (''A. erythronemius''). The American Ornithological Society keeps all four variations conspecific. Taxonomy The sharp-shinned hawk is sometimes separated into four species, with the northern group (''see distribution'') retaining both the scientific name and the common name: sharp-shinned hawk (''A. striatus''). In addition to the nominate taxon (''A. s. striatus''), it includes subspecies ''perobscurus'', ''velox'', ''suttoni'', ''madrensis'', ''fringilloides'', and ''venator''. The t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bicolored Hawk
The bicolored hawk (''Accipiter bicolor'') is a species of bird of prey in the family Accipitridae. It is found in forest, woodland, second growth, plantations, and wooded savanna in southeastern Mexico, Central America, and northern and central South America (as far south as northern Argentina). Though generally uncommon, it is the most common species of ''Accipiter'' in most of its range, but it does not occur at altitudes above such as the highest parts of the Andes. Description At in length and in weight, it is significantly smaller than the northern goshawk of Eurasia and North America, and somewhat smaller than the Cooper's hawk of North America, but among the largest ''Accipiter'' hawks in Central and South America (only the rare grey-bellied hawk is larger). As in other ''Accipiter'' hawks, the female is far larger than the male. Adults are grey above with darker wings and crown, and a banded tail. The underparts typically vary from dark grey to very pale grey, but th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Sparrowhawk
The black sparrowhawk (''Accipiter melanoleucus''), sometimes known as the black goshawk or great sparrowhawk, is the largest African member of the genus ''Accipiter''.Arkive. Black goshawk (''Accipiter melanoleucus''). In: Arkive: Images of Life on Earth.. Retrieved 6 October 2011. It occurs mainly in forest and non-desert areas south of the Sahara, particularly where there are large trees suitable for nesting; favored habitat includes suburban and human-altered landscapes. It preys predominantly on birds of moderate size, such as pigeons and doves, in suburban areas.Curtis O.E., Hockey P.A.R., Koeslag A. 2007Competition with Egyptian geese ''Alopochen aegyptiaca'' overrides environmental factors in determining productivity of Black Sparrowhawks ''Accipiter melanoleucus'' ''Ibis'' 149: 502‐508. Taxonomy There are 2 subspecies of black sparrowhawk: ''Accipiter melanoleucus melanoleucus'', which was named by A. Smith in 1830, and ''Accipiter melanoleucus temminckii'', which was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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