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Goshawk Subfamily
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] |
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 species, such as the tiny hawk. The taxonomy is far from resolved, with some authorities considering the southern 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 three remaining taxa, each considered a monoty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humans
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, and language. Humans are highly social and tend to live in complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established a wide variety of values, social norms, and rituals, which bolster human society. Its intelligence and its desire to understand and influence the environment and to explain and manipulate phenomena have motivated humanity's development of science, philosophy, mythology, religion, and other fields of study. Although some scientists equate the term ''humans'' with all members of the genus ''Homo'', in common usage, it generally refers to ''Homo sapiens'', the only extant member. Anatomically mod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chinese Sparrowhawk
The Chinese sparrowhawk (''Accipiter soloensis'') is a bird of prey in the family Accipitridae. Distribution and habitat It breeds in Southeast China, Taiwan, Korea and Siberia; winters in Indonesia and Philippines, passing through the rest of Southeast Asia. It lives mainly in forests but sometimes lives on edges. Description It is 30–36 cm in length, with the female larger than the male. Adults have prominent black wing tips. The male is grey above, white below and has red eyes. The female has rufous on breast and underwing coverts, and yellow eyes. Juveniles have a grey face, brown upperparts and yellow eyes. The top underparts are streaked, while the thighs are barred. The black wing tips are not as prominent and underwings streaked (except for coverts). Diet In its breeding range, it feeds mainly on frogs A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chestnut-flanked Sparrowhawk
The chestnut-flanked sparrowhawk (''Accipiter castanilius'') is a small west African species of sparrowhawk in the family Accipitridae. Description Chestnut-flanked sparrowhawk has blackish grey upperparts with a very distinctive pattern on the underparts; the breast and belly are heavily barred grey and brown, with chestnut colored flanks. The throat is white and the head is rather broad compared to similar species. The cere is yellow as is the thin eyering which surrounds the red eye. Females and juveniles are browner. They sit tall and have a wingspan of . Distribution The chestnut-flanked sparrowhawk occurs in west central Africa from southern Nigeria through Cameroon and Gabon to Democratic Republic of Congo. It is said to occur in the Upper Guinean forests west of Nigeria but this has not been confirmed. Habitat The chestnut-flanked sparrowhawk is found mainly in lowland tropical rainforest, mainly in the middle storey but it can adapt to dense secondary growth and will a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Goshawk
The brown goshawk (''Accipiter fasciatus'') is a medium-sized bird of prey in the family Accipitridae found in Australia and Oceania, surrounding islands. Description Its upperparts are grey with a chestnut collar; its underparts are mainly rufous, finely barred with white. Thus it has similar colouring to the collared sparrowhawk but is larger. The flight is fast and flexible. The body length is ; the wingspan, . Females are noticeably larger: adult males weigh , and adult females, . Distribution and habitat The brown goshawk is widespread through Australia, Wallacea, New Guinea, New Caledonia, Vanuatu and Fiji. In Australia, it is found mainly in eucalypt forests and woodlands, as well as farmland and urban areas. In the Pacific, it mainly inhabits rainforest. It was also found on Norfolk Island to about 1790, and this may be another undescribed subspecies. However, the lack of specimens from Norfolk Island (1 historical skin and 9 subfossil bones is all the material that h ... [...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 wa ... [...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 the ... [...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 pl ... [...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 male ... [...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 mo ... [...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 com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain
The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head ( cephalization), usually near organs for special senses such as vision, hearing and olfaction. Being the most specialized organ, it is responsible for receiving information from the sensory nervous system, processing those information (thought, cognition, and intelligence) and the coordination of motor control (muscle activity and endocrine system). While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective body segment) of the ventral nerve cord, vertebrate brains develop axially from the midline dorsal nerve cord as a vesicular enlargement at the rostral end of the neural tube, with centralized control over all body segments. All vertebrate brains can be embryonically divided into three parts: the forebrain (prosencep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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