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Tawny Owl
The tawny owl (''Strix aluco''), also called the brown owl, is a stocky, medium-sized owl in the family Strigidae. It is commonly found in woodlands across Europe, as well as western Siberia, and has seven recognized subspecies. The tawny owl's underparts are pale with dark streaks, whilst its upper body may be either brown or grey (in several subspecies, individuals may be of both colours). The tawny owl typically makes its Bird nest, nest in a tree hollow, tree hole where it can protect its eggs and young against potential predators. It is bird migration, non-migratory and highly territorial: as a result, when young birds grow up and leave the parental nest, if they cannot find a vacant territory to claim as their own, they will often starve. The tawny owl is a nocturnal bird of prey. It is able to hunt successfully at night because of its vision, hearing adaptations and its ability to fly silently. It usually hunts by dropping suddenly from a perch and seizing its prey, whic ...
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Carl Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern Taxonomy (biology), taxonomy". Many of his writings were in Latin; his name is rendered in Latin as and, after his 1761 ennoblement, as . Linnaeus was the son of a curate and was born in Råshult, in the countryside of Småland, southern Sweden. He received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and also published the first edition of his ' in the Netherlands. He then returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he co ...
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Infrared
Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those of red light (the longest waves in the visible spectrum), so IR is invisible to the human eye. IR is generally (according to ISO, CIE) understood to include wavelengths from around to . IR is commonly divided between longer-wavelength thermal IR, emitted from terrestrial sources, and shorter-wavelength IR or near-IR, part of the solar spectrum. Longer IR wavelengths (30–100 μm) are sometimes included as part of the terahertz radiation band. Almost all black-body radiation from objects near room temperature is in the IR band. As a form of EMR, IR carries energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon. It was long known that fires e ...
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Rod Cell
Rod cells are photoreceptor cells in the retina of the eye that can function in lower light better than the other type of visual photoreceptor, cone cells. Rods are usually found concentrated at the outer edges of the retina and are used in peripheral vision. On average, there are approximately 92 million rod cells (vs ~4.6 million cones) in the human retina. Rod cells are more sensitive than cone cells and are almost entirely responsible for night vision. However, rods have little role in color vision, which is the main reason why colors are much less apparent in dim light. Structure Rods are a little longer and leaner than cones but have the same basic structure. Opsin-containing disks lie at the end of the cell adjacent to the retinal pigment epithelium, which in turn is attached to the inside of the eye. The stacked-disc structure of the detector portion of the cell allows for very high efficiency. Rods are much more common than cones, with about 120 million rod cells ...
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Binocular Vision
Binocular vision is seeing with two eyes. The Field_of_view, field of view that can be surveyed with two eyes is greater than with one eye. To the extent that the visual fields of the two eyes overlap, #Depth, binocular depth can be perceived. This allows objects to be recognized more quickly, camouflage to be detected, spatial relationships to be perceived more quickly and accurately (#Stereopsis, stereopsis) and perception to be less susceptible to optical illusions, optical illusions. In secion #Medical, Medical attention is paid to the occurrence, defects and sharpness of binocular vision. In section #Biological, Biological the occurrence of binocular vision in animals is described. Geometric terms When the left eye (LE) and the right eye (RE) observe two objects X and Y, the following concepts are important:Krol J.D.(1982),"Perceptual ghosts in stereopsis, a ghosly problem in binocular vision", PhD thesis ISBN 90-9000382-7.Koenderink J.J.;van Doorn A.J. (1976) "Geometry of ...
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Ural Owl
The Ural owl (''Strix uralensis'') is a large nocturnal owl. It is a member of the true owl family, ''Strigidae''. The Ural owl is a member of the genus ''Strix (genus), Strix'', that is also the origin of the family's name under Linnaean taxonomy.Sclater, P. L. (1879). ''Remarks on the Nomenclature of the British Owls, and on the Arrangement of the Order Striges''. Ibis, 21(3), 346-352. Both its common name and scientific name refer to the Ural Mountains of Russia where the Type (biology), type specimen was collected. However, this species has an extremely broad distribution that extends as far west as much of Scandinavia, montane eastern Europe, and, sporadically, central Europe, thence sweeping across the Palearctic broadly through Russia to as far east as Sakhalin and throughout Japan.Voous, K.H. (1988). ''Owls of the Northern Hemisphere''. The MIT Press, . The Ural owl may include up to 15 subspecies, but most likely the number may be slightly fewer if accounting for Cline (bi ...
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Eurasian Eagle-owl
The Eurasian eagle-owl (''Bubo bubo'') is a species of eagle-owl, a type of bird that resides in much of Eurasia. It is often just called the eagle-owl in Europe and Asia. It is one of the largest species of owl. Females can grow to a total length of , with a wingspan of . Males are slightly smaller.''Owls of the World: A Photographic Guide'' by Mikkola, H. Firefly Books (2012), This bird has distinctive ear tufts, with upper parts that are mottled with darker blackish colouring and tawny. The wings and tail are barred. The underparts are a variably hued buff, streaked with darker colouring. The facial disc is not very defined. The orange eyes are distinctive.Penteriani, V., & del Mar Delgado, M. (2019). ''The eagle owl''. Bloomsbury Publishing. At least 12 subspecies of the Eurasian eagle-owl are described. Eurasian eagle-owls are found in many habitats; mostly Mountain ecosystems, mountainous and Rock (geology), rocky areas, often near varied woodland edge and near shrubby a ...
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Great Grey Owl
The great grey owl (''Strix nebulosa'') (also great gray owl in American English) is a true owl, and is the world's largest species of owl by length. It is distributed across the Northern Hemisphere, and it is the only species in the genus ''Strix (genus), Strix'' found in both Eastern and Western Hemispheres. In some areas it is also called the Phantom of the North, cinereous owl (this name is also used for ''Strix sartorii''), spectral owl, Lapland owl, spruce owl, bearded owl, and sooty owl. Description Adults have large rounded heads with grey faces and yellow eyes with darker circles around them. The underparts are light with dark streaks; the upper parts are grey with pale bars. This owl does not have ear tufts and has the largest facial disc of any bird of prey, raptor. There is a white collar or "bow-tie" just below the beak. The long tail tapers to a rounded end. In terms of length, the great grey owl is believed to exceed the Eurasian eagle-owl and the Blakiston's fis ...
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Flight Feather
Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tail are called rectrices ( or ), singular rectrix (). The primary function of the flight feathers is to aid in the generation of both thrust and lift, thereby enabling flight. The flight feathers of some birds perform additional functions, generally associated with territorial displays, courtship rituals or feeding methods. In some species, these feathers have developed into long showy plumes used in visual courtship displays, while in others they create a sound during display flights. Tiny serrations on the leading edge of their remiges help owls to fly silently (and therefore hunt more successfully), while the extra-stiff rectrices of woodpeckers help them to brace against tree trunks as they hammer on them. Even flightless birds still r ...
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Sexual Dimorphism
Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, dioecious species, which consist of most animals and some plants. Differences may include secondary sex characteristics, size, weight, color, markings, or behavioral or cognitive traits. Male-male reproductive competition has evolved a diverse array of sexually dimorphic traits. Aggressive utility traits such as "battle" teeth and blunt heads reinforced as battering rams are used as weapons in aggressive interactions between rivals. Passive displays such as ornamental feathering or song-calling have also evolved mainly through sexual selection. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', when both biological sexes are phenotype, ...
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Plumage
Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can be different colour morph (zoology), morphs. The placement of feathers on a bird is not haphazard but rather emerges in organized, overlapping rows and groups, and these are known by standardized names. Most birds moult twice a year, resulting in a breeding or ''nuptial plumage'' and a ''basic plumage''. Many ducks and some other species such as the red junglefowl have males wearing a bright nuptial plumage while breeding and a drab ''eclipse plumage'' for some months afterward. The painted bunting's juveniles have two inserted moults in their first autumn, each yielding plumage like an adult female. The first starts a few days after fledging replacing the ''juvenile plumage'' with an ''auxiliary formative plumage''; the second a month o ...
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Morphotype
In biology, polymorphism is the occurrence of two or more clearly different morphs or forms, also referred to as alternative ''phenotypes'', in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating). Ford E.B. 1965. ''Genetic polymorphism''. Faber & Faber, London. Put simply, polymorphism is when there are two or more possibilities of a trait on a gene. For example, there is more than one possible trait in terms of a jaguar's skin colouring; they can be light morph or dark morph. Due to having more than one possible variation for this gene, it is termed 'polymorphism'. However, if the jaguar has only one possible trait for that gene, it would be termed "monomorphic". For example, if there was only one possible skin colour that a jaguar could have, it would be termed monomorphic. The term polyphenism can be used to clarify that the different forms arise from the s ...
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