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138-413: Strigidae Tytonidae Ogygoptyngidae ( fossil ) Palaeoglaucidae ( fossil ) Protostrigidae ( fossil ) Sophiornithidae ( fossil ) Strigidae sensu Sibley & Ahlquist Owls are birds from the order Strigiformes ( / ˈ s t r ɪ dʒ ə f ɔːr m iː z / ), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance,

276-630: A binomial name , categorising them into different genera. However, ornithology did not emerge as a specialised science until the Victorian era—with the popularization of natural history, and the collection of natural objects such as bird eggs and skins. This specialization led to the formation in Britain of the British Ornithologists' Union in 1858. In 1859, the members founded its journal The Ibis . The sudden spurt in ornithology

414-635: A menagerie and sponsored translations of Arabic texts, among which the popular Arabic work known as the Liber Moaminus by an unknown author which was translated into Latin by Theodore of Antioch from Syria in 1240-1241 as the De Scientia Venandi per Aves , and also Michael Scotus (who had removed to Palermo) translated Ibn Sīnā 's Kitāb al-Ḥayawān of 1027 for the Emperor, a commentary and scientific update of Aristotle's work which

552-619: A Latin translation of Aristotle's work on animals from Arabic here around 1215, which was disseminated widely and was the first time in a millennium that this foundational text on zoology became available to Europeans. Falconry was popular in the Norman court in Sicily, and a number of works on the subject were written in Palermo . Emperor Frederick II of Hohenstaufen (1194–1250) learned about an falconry during his youth in Sicily and later built up

690-697: A classification of birds, De Differentiis Avium (around 1572), that was based on structure and habits. Konrad Gesner wrote the Vogelbuch and Icones avium omnium around 1557. Like Gesner, Ulisse Aldrovandi , an encyclopedic naturalist, began a 14-volume natural history with three volumes on birds, entitled ornithologiae hoc est de avibus historiae libri XII , which was published from 1599 to 1603. Aldrovandi showed great interest in plants and animals, and his work included 3000 drawings of fruits, flowers, plants, and animals, published in 363 volumes. His Ornithology alone covers 2000 pages and included such aspects as

828-478: A facial ruff, which creates an anterior-facing, concave wall that cups the sound into the ear structure. This facial ruff is poorly defined in some species, and prominent, nearly encircling the face, in other species. The facial disk also acts to direct sound into the ears, and a downward-facing, sharply triangular beak minimizes sound reflection away from the face. The shape of the facial disk is adjustable at will to focus sounds more effectively. The prominences above

966-453: A few centimetres of their eyes. Caught prey can be felt by owls with the use of filoplumes —hairlike feathers on the beak and feet that act as "feelers". Their far vision, particularly in low light, is exceptionally good. Owls can rotate their heads and necks as much as 270°. Owls have 14 neck vertebrae — humans have only seven — and their vertebral circulatory systems are adapted to allow them to rotate their heads without cutting off blood to

1104-506: A few species specialize in hunting fish . They are found in all regions of the Earth except the polar ice caps and some remote islands. A group of owls is called a "parliament". Owls possess large, forward-facing eyes and ear-holes, a hawk -like beak , a flat face, and usually a conspicuous circle of feathers, a facial disc , around each eye. The feathers making up this disc can be adjusted to sharply focus sounds from varying distances onto

1242-462: A force over 130 N to release prey in its talons. An owl's talons, like those of most birds of prey, can seem massive in comparison to the body size outside of flight. The Tasmanian masked owl has some of the proportionally longest talons of any bird of prey; they appear enormous in comparison to the body when fully extended to grasp prey. An owl's claws are sharp and curved. The family Tytonidae has inner and central toes of about equal length, while

1380-419: A great horned owl's head are commonly mistaken as its ears. This is not the case; they are merely feather tufts. The ears are on the sides of the head in the usual location (in two different locations as described above). While the auditory and visual capabilities of the owl allow it to locate and pursue its prey, the talons and beak of the owl do the final work. The owl kills its prey using these talons to crush

1518-470: A hundredth the size of the largest, the Eurasian eagle-owl and Blakiston's fish owl , owls generally share an extremely similar body plan. They tend to have large heads, short tails, cryptic plumage , and round facial discs around the eyes. The family is generally arboreal (with a few exceptions like the burrowing owl ) and obtain their food on the wing. The wings are large, broad, rounded, and long. As

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1656-401: A large, broad head, binocular vision , binaural hearing , sharp talons , and feathers adapted for silent flight. Exceptions include the diurnal northern hawk-owl and the gregarious burrowing owl . Owls are divided into two families : the true (or typical) owl family, Strigidae, and the barn owl family, Tytonidae. Owls hunt mostly small mammals , insects , and other birds, although

1794-619: A male's sexual advances, smaller male owls that have the ability to escape unreceptive females are more likely to have been selected. If the character is stable, there can be different optimums for both sexes. Selection operates on both sexes at the same time; therefore it is necessary to explain not only why one of the sexes is relatively bigger, but also why the other sex is smaller. If owls are still evolving toward smaller bodies and longer wing chords, according to V. Geodakyan's Evolutionary Theory of Sex, males should be more advanced on these characters. Males are viewed as an evolutionary vanguard of

1932-448: A model for many studies in non-mammalian immunology. Studies in bird behaviour include the use of tamed and trained birds in captivity. Studies on bird intelligence and song learning have been largely laboratory-based. Field researchers may make use of a wide range of techniques such as the use of dummy owls to elicit mobbing behaviour, and dummy males or the use of call playback to elicit territorial behaviour and thereby to establish

2070-593: A policy of the British Ornithologists' Union to keep out women. Unlike the RSPB, which was primarily conservation oriented, the British Trust for Ornithology was started in 1933 with the aim of advancing ornithological research. Members were often involved in collaborative ornithological projects. These projects have resulted in atlases which detail the distribution of bird species across Britain. In Canada, citizen scientist Elsie Cassels studied migratory birds and

2208-557: A population, and sexual dimorphism on the character, as an evolutionary "distance" between the sexes. "Phylogenetic rule of sexual dimorphism" states that if there exists a sexual dimorphism on any character, then the evolution of this trait goes from the female form toward the male one. All owls are carnivorous birds of prey and live on diets of insects, small rodents and lagomorphs. Some owls are also specifically adapted to hunt fish. They are very adept in hunting in their respective environments. Since owls can be found in nearly all parts of

2346-525: A relatively small skull is that the eye of the owl has become tubular in shape. This shape is found in other so-called nocturnal eyes, such as the eyes of strepsirrhine primates and bathypelagic fishes . Since the eyes are fixed into these sclerotic tubes, they are unable to move the eyes in any direction. Instead of moving their eyes, owls swivel their heads to view their surroundings. Owls' heads are capable of swiveling through an angle of roughly 270°, easily enabling them to see behind them without relocating

2484-586: A resource for taxonomic studies. The use of bird skins to document species has been a standard part of systematic ornithology. Bird skins are prepared by retaining the key bones of the wings, legs, and skull along with the skin and feathers. In the past, they were treated with arsenic to prevent fungal and insect (mostly dermestid ) attack. Arsenic, being toxic, was replaced by less-toxic borax . Amateur and professional collectors became familiar with these skinning techniques and started sending in their skins to museums, some of them from distant locations. This led to

2622-403: A spurt of bird studies in this area. The study of imprinting behaviour in ducks and geese by Konrad Lorenz and the studies of instinct in herring gulls by Nicolaas Tinbergen led to the establishment of the field of ethology . The study of learning became an area of interest and the study of bird songs has been a model for studies in neuroethology. The study of hormones and physiology in

2760-412: A strong advantage over prey alert to the slightest sound in the night. A silent, slow flight is not as necessary for diurnal and crepuscular owls given that prey can usually see an owl approaching. Owls' feathers are generally larger than the average birds' feathers, have fewer radiates, longer pennulum, and achieve smooth edges with different rachis structures. Serrated edges along the owl's remiges bring

2898-943: A tract on falconry, and introduced the words "incubation" and "oviparous" into the English language. Towards the late 18th century, Mathurin Jacques Brisson (1723–1806) and Comte de Buffon (1707–1788) began new works on birds. Brisson produced a six-volume work Ornithologie in 1760 and Buffon's included nine volumes (volumes 16–24) on birds Histoire naturelle des oiseaux (1770–1785) in his work on science Histoire naturelle générale et particulière (1749–1804). Jacob Temminck sponsored François Le Vaillant [1753–1824] to collect bird specimens in Southern Africa and Le Vaillant's six-volume Histoire naturelle des oiseaux d'Afrique (1796–1808) included many non-African birds. His other bird books produced in collaboration with

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3036-462: A transparent top and visible cues such as the direction of sunlight may be controlled using mirrors or the positions of the stars simulated in a planetarium . The entire genome of the domestic fowl ( Gallus gallus ) was sequenced in 2004, and was followed in 2008 by the genome of the zebra finch ( Taeniopygia guttata ). Such whole-genome sequencing projects allow for studies on evolutionary processes involved in speciation . Associations between

3174-462: A two-part article in The Auk , noting the tensions between amateurs and professionals, and suggested the possibility that the "vast army of bird lovers and bird watchers could begin providing the data scientists needed to address the fundamental problems of biology." The amateur ornithologist Harold F. Mayfield noted that the field was also funded by non-professionals. He noted that in 1975, 12% of

3312-520: A very different way (such as the terrestrial Sophiornithidae ). The Paleocene genera Berruornis and Ogygoptynx show that owls were already present as a distinct lineage some 60–57 million years ago (Mya), hence, possibly also some 5 million years earlier, at the extinction of the non-avian dinosaurs . This makes them one of the oldest known groups of non- Galloanserae landbirds. The supposed " Cretaceous owls" Bradycneme and Heptasteornis are apparently non- avialan maniraptors . During

3450-412: Is a physical difference between males and females of a species. Female owls are typically larger than the males. The degree of size dimorphism varies across multiple populations and species, and is measured through various traits, such as wing span and body mass. One theory suggests that selection has led males to be smaller because it allows them to be efficient foragers . The ability to obtain more food

3588-445: Is able to determine the direction from which the sound is coming by the minute difference in time that it takes for the sound waves to penetrate the left and right ears. The owl turns its head until the sound reaches both ears at the same time, at which point it is directly facing the source of the sound. This time difference between ears is about 30 microseconds. Behind the ear openings are modified, dense feathers, densely packed to form

3726-492: Is advantageous during breeding season. In some species, female owls stay at their nest with their eggs while it is the responsibility of the male to bring back food to the nest. If food is scarce, the male first feeds himself before feeding the female. Small birds, which are agile, are an important source of food for owls. Male burrowing owls have been observed to have longer wing chords than females, despite being smaller than females. Furthermore, owls have been observed to be roughly

3864-467: Is another technique that has the advantage of preserving stomach contents and anatomy, although it tends to shrink, making it less reliable for morphometrics. The study of birds in the field was helped enormously by improvements in optics. Photography made it possible to document birds in the field with great accuracy. High-power spotting scopes today allow observers to detect minute morphological differences that were earlier possible only by examination of

4002-1344: Is based on the results of the study by Salter and collaborators published in 2020. The subfamilies are those defined by Edward Dickinson and James Van Remsen Jr. in 2013. A genetic study published in 2021 suggested that the genus Scotopelia may be embedded within Ketupa . Ninox – 36 species: hawk-owls and boobooks Uroglaux – Papuan hawk-owl (position uncertain) Aegolius – 5 species Athene – 9 species Glaucidium – 29 species: pygmy owls Surnia – northern hawk-owl Margarobyas – bare-legged owl (position uncertain) Taenioptynx – 2 species Micrathene – elf owl Xenoglaux – long-whiskered owlet Otus – 58 species: scops owls Asio – 9 species in total Ptilopsis – 2 species Jubula – maned owl (position uncertain) Bubo – 10 species: eagle-owls, horned-owls and snowy owl Ketupa – 12 species: fish owls and eagle-owls Scotopelia – 3 species: fishing owls Megascops – 25 species: screech owls Gymnasio – Puerto Rican owl Psiloscops – flammulated owl Strix – 22 species: earless owls Lophostrix – crested owl Pulsatrix – 3 species The 235 extant or recently extinct species are assigned to 23 genera : The fossil database for Strigiformes

4140-447: Is commonplace knowledge to the mere collector, such as that hunting parties often travel more or less in circles. David Lack's studies on population ecology sought to find the processes involved in the regulation of population based on the evolution of optimal clutch sizes. He concluded that population was regulated primarily by density-dependent controls , and also suggested that natural selection produces life-history traits that maximize

4278-467: Is declining at a more rapid pace. This invasion by barred owls occurred about 50 years ago in the Pacific Northwest , and despite their low numbers, they are considered an invasive species because of the harm done to native spotted owls. In this competition for resources , hunting locations and general niches, the barred owl is pushing the spotted owl to local extinction . It is thought that

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4416-1064: Is disputed. See below cladogram : Cathartiformes (New World vultures) [REDACTED] Accipitriformes ( hawks and relatives) [REDACTED] Strigiformes (owls) [REDACTED] Coliiformes (mouse birds) Leptosomiformes (cuckoo roller) Trogoniformes (trogons and quetzals) [REDACTED] Bucerotiformes ( hornbills and relatives) Coraciiformes ( kingfishers and relatives) [REDACTED] Piciformes ( woodpeckers and relatives) Cariamiformes (seriemas) [REDACTED] Falconiformes (falcons) [REDACTED] Psittaciformes (parrots) [REDACTED] Passeriformes (passerines) [REDACTED] Cladogram of Telluraves relationships based on Braun & Kimball (2021) Some 220 to 225 extant species of owls are known, subdivided into two families: 1. true owls or typical owls family ( Strigidae ) and 2. barn-owls family ( Tytonidae ). Some entirely extinct families have also been erected based on fossil remains; these differ much from modern owls in being less specialized or specialized in

4554-620: Is extinct and all extant ostrich races are today restricted to Africa . Other old writings such as the Vedas (1500–800 BC) demonstrate the careful observation of avian life histories and include the earliest reference to the habit of brood parasitism by the Asian koel ( Eudynamys scolopaceus ). Like writing, the early art of China, Japan, Persia, and India also demonstrate knowledge, with examples of scientifically accurate bird illustrations. Aristotle in 350 BC in his History of animals noted

4692-542: Is highly diverse and shows an origin from ~60MYA into the Pleistocene. The maximum age range for the Strigiformes clade extends to 68.6MYA. Placement unresolved: The supposed fossil heron "Ardea" lignitum (Late Pliocene of Germany) was apparently a strigid owl, possibly close to Bubo . The Early–Middle Eocene genus Palaeoglaux from west-central Europe is sometimes placed here, but given its age, it

4830-441: Is occurring in these two families, there is a concern with the barred owls encroaching on the spotted owl's North American habitats, causing a decline of the spotted owl. As noted above, these species prefer mature forests which, due to deforestation, are at limited supply and take a long time to reestablish after deforestation has occurred. Because the northern spotted owl shares its territories and competes with other species, it

4968-554: Is often regarded as the greatest ornithological work in history. The emergence of ornithology as a scientific discipline began in the 18th century, when Mark Catesby published his two-volume Natural History of Carolina, Florida, and the Bahama Islands , a landmark work which included 220 hand-painted engravings and was the basis for many of the species Carl Linnaeus described in the 1758 Systema Naturae . Linnaeus' work revolutionised bird taxonomy by assigning every species

5106-559: Is probably better considered its own family for the time being. Ornithologist While early ornithology was principally concerned with descriptions and distributions of species, ornithologists today seek answers to very specific questions, often using birds as models to test hypotheses or predictions based on theories. Most modern biological theories apply across life forms, and the number of scientists who identify themselves as "ornithologists" has therefore declined. A wide range of tools and techniques are used in ornithology, both inside

5244-498: Is the case with most birds of prey , in many owl species females are larger than males. Because of their nocturnal habits, they tend not to exhibit sexual dimorphism in their plumage. Specialized feathers and wing shape suppress the noise produced by flying, both taking off, flapping and gliding. This silent flight allows owls to hunt without being heard by their prey. Owls possess three physical attributes that are thought to contribute to their silent flight capability. First, on

5382-584: Is the first such record of North American birds, significantly antedating Audubon. In the early 19th century, Lewis and Clark studied and identified many birds in the western United States. John James Audubon , born in 1785, observed and painted birds in France and later in the Ohio and Mississippi valleys. From 1827 to 1838, Audubon published The Birds of America , which was engraved by Robert Havell Sr. and his son Robert Havell Jr. Containing 435 engravings, it

5520-622: Is the more common number. In at least one species, female owls do not mate with the same male for a lifetime. Female burrowing owls commonly travel and find other mates, while the male stays in his territory and mates with other females. Recent phylogenetic studies place owls within the clade Telluraves , most closely related to the Accipitrimorphae and the Coraciimorphae , although the exact placement within Telluraves

5658-426: Is used to tear the tissue and kill. The sharp lower edge of the upper bill works in coordination with the sharp upper edge of the lower bill to deliver this motion. The downward-facing beak allows the owl's field of vision to be clear, as well as directing sound into the ears without deflecting sound waves away from the face. The coloration of the owl's plumage plays a key role in its ability to sit still and blend into

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5796-573: The Bulo Burti boubou ( Laniarius liberatus , no longer a valid species) and the Bugun liocichla ( Liocichla bugunorum ), using blood, DNA and feather samples as the holotype material, has now become possible. Other methods of preservation include the storage of specimens in spirit. Such wet specimens have special value in physiological and anatomical study, apart from providing better quality of DNA for molecular studies. Freeze drying of specimens

5934-546: The Paleogene , the Strigiformes radiated into ecological niches now mostly filled by other groups of birds. The owls as known today, though, evolved their characteristic morphology and adaptations during that time, too. By the early Neogene , the other lineages had been displaced by other bird orders, leaving only barn owls and typical owls. The latter at that time was usually a fairly generic type of (probably earless) owl similar to today's North American spotted owl or

6072-467: The chicken and poultry techniques. He used a number of traits including behaviour, particularly bathing and dusting, to classify bird groups. William Turner 's Historia Avium ( History of Birds ), published at Cologne in 1544, was an early ornithological work from England. He noted the commonness of kites in English cities where they snatched food out of the hands of children. He included folk beliefs such as those of anglers. Anglers believed that

6210-421: The osprey emptied their fishponds and would kill them, mixing the flesh of the osprey into their fish bait. Turner's work reflected the violent times in which he lived, and stands in contrast to later works such as Gilbert White 's 1789 The Natural History and Antiquities of Selborne that were written in a tranquil era. In the 17th century, Francis Willughby (1635–1672) and John Ray (1627–1705) created

6348-446: The spotted owl and the barred owl (both of which are true owls) . This competition is related to deforestation , and therefore a reduction in niche quantity and quality. This deforestation is more specifically the result of overlogging and forest fires . These two species of owl are known to traditionally live in mature forests of old and tall trees, which at this point in time are mostly limited to public lands . As niche overlap

6486-653: The uropygial gland , informally the "preen" or "oil" gland, as most birds do, to spread oils across their plumage through preening. This makes them highly vulnerable to heavy rain when they are unable to hunt. Historically, they would switch to hunting indoors in wet weather, using barns and other agricultural buildings, but the decline in the numbers of these structures in the 20th and 21st centuries has reduced such opportunities. The lack of waterproofing means that barn owls are also susceptible to drowning, in drinking troughs and other structures with smooth sides. The Barn Owl Trust provides advice on how this can be mitigated, by

6624-506: The 1820s and 1830s, with pioneers such as J. Dovaston (who also pioneered in the use of bird feeders), but instruction manuals did not begin to insist on the use of optical aids such as "a first-class telescope" or "field glass" until the 1880s. The rise of field guides for the identification of birds was another major innovation. The early guides such as Thomas Bewick's two-volume guide and William Yarrell's three-volume guide were cumbersome, and mainly focused on identifying specimens in

6762-454: The 19th century. In 1901, Robert Ridgway wrote in the introduction to The Birds of North and Middle America that: There are two essentially different kinds of ornithology: systematic or scientific, and popular. The former deals with the structure and classification of birds, their synonymies, and technical descriptions. The latter treats of their habits, songs, nesting, and other facts pertaining to their life histories. This early idea that

6900-537: The Birds by Roger Tory Peterson in 1934, to Birds of the West Indies published in 1936 by Dr. James Bond - the same who inspired the amateur ornithologist Ian Fleming in naming his famous literary spy . The interest in birdwatching grew in popularity in many parts of the world, and the possibility for amateurs to contribute to biological studies was soon realized. As early as 1916, Julian Huxley wrote

7038-609: The Elder described birds, among other creatures, in his Historia Naturalis . The earliest record of falconry comes from the reign of Sargon II (722–705 BC) in Assyria . Falconry is thought to have made its entry to Europe only after AD 400, brought in from the east after invasions by the Huns and Alans . Starting from the eighth century, numerous Arabic works on the subject and general ornithology were written, as well as translations of

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7176-562: The European tawny owl ; the diversity in size and ecology found in typical owls today developed only subsequently. Around the Paleogene-Neogene boundary (some 25 Mya), barn owls were the dominant group of owls in southern Europe and adjacent Asia at least; the distribution of fossil and present-day owl lineages indicates that their decline is contemporary with the evolution of the different major lineages of true owls, which for

7314-544: The Mediterranean, and Pierre Belon , who described the fish and birds that he had seen in France and the Levant. Belon's Book of Birds (1555) is a folio volume with descriptions of some 200 species. His comparison of the skeleton of humans and birds is considered as a landmark in comparative anatomy . Volcher Coiter (1534–1576), a Dutch anatomist, made detailed studies of the internal structures of birds and produced

7452-486: The Victorian era observed the variations in bird forms and habits across geographic regions, noting local specialization and variation in widespread species. The collections of museums and private collectors grew with contributions from various parts of the world. The naming of species with binomials and the organization of birds into groups based on their similarities became the main work of museum specialists. The variations in widespread birds across geographical regions caused

7590-430: The age of owls. The relative ages of the feathers are differentiated by the intensity of fluorescence that they emit when the primaries and secondaries are exposed to black light . This method helps to detect the subtle differences between third and fourth generation feathers, whereas looking at wear and color makes age determination difficult. It has been noted that there is some competition for niche space between

7728-497: The artist Barraband are considered among the most valuable illustrated guides ever produced. Louis Pierre Vieillot (1748–1831) spent 10 years studying North American birds and wrote the Histoire naturelle des oiseaux de l'Amerique septentrionale (1807–1808?). Vieillot pioneered in the use of life histories and habits in classification. Alexander Wilson composed a nine-volume work, American Ornithology , published 1808-1814, which

7866-440: The behaviour, with many names being onomatopoeic , and still in use. Traditional knowledge may also involve the use of birds in folk medicine and knowledge of these practices are passed on through oral traditions (see ethno-ornithology ). Hunting of wild birds as well as their domestication would have required considerable knowledge of their habits. Poultry farming and falconry were practised from early times in many parts of

8004-431: The boundaries of bird territories. Studies of bird migration including aspects of navigation, orientation, and physiology are often studied using captive birds in special cages that record their activities. The Emlen funnel , for instance, makes use of a cage with an inkpad at the centre and a conical floor where the ink marks can be counted to identify the direction in which the bird attempts to fly. The funnel can have

8142-409: The brain . Specifically, the foramina in their vertebrae through which the vertebral arteries pass are about 10 times the diameter of the artery, instead of about the same size as the artery, as is the case in humans; the vertebral arteries enter the cervical vertebrae higher than in other birds, giving the vessels some slack, and the carotid arteries unite in a very large anastomosis or junction,

8280-581: The brain. Several owl species also have fluorescent pigments called porphyrins under their wings. A large group of pigments defined by nitrogen-containing pyrole rings, including chlorophyll and heme (in animal blood), make up the porphyrins. Other bird species will use porphyrins to pigment eggshells in the oviduct. Owl species, however, use porphyrins as a pigment in their plumage. Porphyrins are most prevalent in new feathers and are easily destroyed by sunlight. Porphyrin pigments in feathers fluoresce under UV light, allowing biologists to more accurately classify

8418-427: The categories of those that are applicable to specimens and those that are used in the field, but the classification is rough and many analysis techniques are usable both in the laboratory and field or may require a combination of field and laboratory techniques. The earliest approaches to modern bird study involved the collection of eggs, a practice known as oology . While collecting became a pastime for many amateurs,

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8556-528: The control of behaviour has also been aided by bird models. These have helped in finding the proximate causes of circadian and seasonal cycles. Studies on migration have attempted to answer questions on the evolution of migration, orientation, and navigation. The growth of genetics and the rise of molecular biology led to the application of the gene-centered view of evolution to explain avian phenomena. Studies on kinship and altruism, such as helpers , became of particular interest. The idea of inclusive fitness

8694-450: The deciduous woodland it prefers for its habitat. Likewise, the mottled wood owl ( Strix ocellata ) displays shades of brown, tan, and black, making the owl nearly invisible in the surrounding trees, especially from behind. Usually, the only tell-tale sign of a perched owl is its vocalizations or its vividly colored eyes. Most owls are nocturnal , actively hunting their prey in darkness. Several types of owls are crepuscular —active during

8832-412: The descriptions of bird species. These skin collections have been used in more recent times for studies on molecular phylogenetics by the extraction of ancient DNA . The importance of type specimens in the description of species make skin collections a vital resource for systematic ornithology. However, with the rise of molecular techniques, establishing the taxonomic status of new discoveries, such as

8970-478: The development of the discipline of landscape ecology . John Hurrell Crook studied the behaviour of weaverbirds and demonstrated the links between ecological conditions, behaviour, and social systems. Principles from economics were introduced to the study of biology by Jerram L. Brown in his work on explaining territorial behaviour. This led to more studies of behaviour that made use of cost-benefit analyses . The rising interest in sociobiology also led to

9108-559: The distribution patterns of birds. For Darwin, the problem was how species arose from a common ancestor, but he did not attempt to find rules for delineation of species. The species problem was tackled by the ornithologist Ernst Mayr , who was able to demonstrate that geographical isolation and the accumulation of genetic differences led to the splitting of species . Early ornithologists were preoccupied with matters of species identification. Only systematics counted as true science and field studies were considered inferior through much of

9246-414: The ears. Hearing in owls is highly sensitive and the ears are asymmetrical allowing the owl to localise a sound in multiple directions. Owls can pinpoint the position of prey, such as a squeaking mouse, by computing when the sound from the object reaches the owl's ears. If the sound reaches the left ear first, the mouse must be to the left of the owl. The owl's brain will then direct the head to directly face

9384-499: The editorial policy of the journal, leading both to a unification of field and laboratory studies and a shift of research from museums to universities. Ornithology in the United States continued to be dominated by museum studies of morphological variations, species identities, and geographic distributions, until it was influenced by Stresemann's student Ernst Mayr . In Britain, some of the earliest ornithological works that used

9522-423: The environment, making it nearly invisible to prey. Owls tend to mimic the coloration and sometimes the texture patterns of their surroundings, the barn owl being an exception. The snowy owl ( Bubo scandiacus ) appears nearly bleach-white in color with a few flecks of black, mimicking their snowy surroundings perfectly, while the speckled brown plumage of the tawny owl ( Strix aluco ) allows it to lie in wait among

9660-492: The environment. Camera traps have been found to be a useful tool for the detection and documentation of elusive species, nest predators and in the quantitative analysis of frugivory, seed dispersal and behaviour. Many aspects of bird biology are difficult to study in the field. These include the study of behavioural and physiological changes that require a long duration of access to the bird. Nondestructive samples of blood or feathers taken during field studies may be studied in

9798-511: The expression of Bmp4 have been shown to be associated with changes in the growth and shape of the beak. The chicken has long been a model organism for studying vertebrate developmental biology . As the embryo is readily accessible, its development can be easily followed (unlike mice ). This also allows the use of electroporation for studying the effect of adding or silencing a gene. Other tools for perturbing their genetic makeup are chicken embryonic stem cells and viral vectors . With

9936-512: The expression of genes and behaviour may be studied using candidate genes. Variations in the exploratory behaviour of great tits ( Parus major ) have been found to be linked with a gene orthologous to the human gene DRD4 (Dopamine receptor D4) which is known to be associated with novelty-seeking behaviour. The role of gene expression in developmental differences and morphological variations have been studied in Darwin's finches . The difference in

10074-399: The family Strigidae has an inner toe that is distinctly shorter than the central one. These different morphologies allow efficiency in capturing prey specific to the different environments they inhabit. The beak of the owl is short, curved, and downward-facing, and typically hooked at the tip for gripping and tearing its prey. Once prey is captured, the scissor motion of the top and lower bill

10212-539: The family Strigidae was divided into two sister clades and some of the traditional genera were paraphyletic . The placement of three monotypic genera remained uncertain due to the degraded nature of the available DNA. Based on these results Frank Gill , Pamela Rasmussen and David Donsker updated the online list of world birds that they maintain on behalf of the International Ornithological Committee (IOC). The cladogram below

10350-746: The feathers of their prey to signal their breeding status to members within the same species. Some species of owl are migratory. One such species, the northern saw-whet owl , migrates south even when food and resources are ample in the north. Some owls have a higher survival rate and are more likely to reproduce in a habitat that contains a mixture of old growth forests and other vegetation types. Old growth forests provide ample dark areas for owls to hide from predators Like many organisms, spotted owls rely on forest fires to create their habitat and provide areas for foraging. Unfortunately, climate change and intentional fire suppression have altered natural fire habits. Owls avoid badly burned areas but they benefit from

10488-457: The first major system of bird classification that was based on function and morphology rather than on form or behaviour. Willughby's Ornithologiae libri tres (1676) completed by John Ray is sometimes considered to mark the beginning of scientific ornithology. Ray also worked on Ornithologia , which was published posthumously in 1713 as Synopsis methodica avium et piscium . The earliest list of British birds, Pinax Rerum Naturalium Britannicarum ,

10626-439: The fitness of individuals. Others, such as Wynne-Edwards , interpreted population regulation as a mechanism that aided the "species" rather than individuals . This led to widespread and sometimes bitter debate on what constituted the "unit of selection". Lack also pioneered the use of many new tools for ornithological research, including the idea of using radar to study bird migration. Birds were also widely used in studies of

10764-415: The flapping of the wing down to a nearly silent mechanism. The serrations are more likely reducing aerodynamic disturbances, rather than simply reducing noise. The surface of the flight feathers is covered with a velvety structure that absorbs the sound of the wing moving. These unique structures reduce noise frequencies above 2 kHz, making the sound level emitted drop below the typical hearing spectrum of

10902-491: The formation of huge collections of bird skins in museums in Europe and North America. Many private collections were also formed. These became references for comparison of species, and the ornithologists at these museums were able to compare species from different locations, often places that they themselves never visited. Morphometrics of these skins, particularly the lengths of the tarsus, bill, tail, and wing became important in

11040-429: The genus Glaucidium and the northern hawk-owl have eye patches on the backs of their heads, apparently to convince other birds they are being watched at all times. Numerous nocturnal species have ear-tufts, feathers on the sides of the head that are thought to have a camouflage function, breaking up the outline of a roosting bird. The feathers of the facial disc are arranged in order to increase sound delivered to

11178-503: The ground in brushy areas typically of cedar forests. These owls eat mice, and perch in trees at eye level. Their main predators are barred owls and great horned owls. The family Strigidae was introduced by the English zoologist William Elford Leach in a guide to the contents of the British Museum published in 1819. A molecular phylogenetic study of the owls by Jessie Salter and collaborators published in 2020 found that

11316-580: The habit of bird migration , moulting, egg laying, and lifespans, as well as compiling a list of 170 different bird species. However, he also introduced and propagated several myths, such as the idea that swallows hibernated in winter, although he noted that cranes migrated from the steppes of Scythia to the marshes at the headwaters of the Nile . The idea of swallow hibernation became so well established that even as late as in 1878, Elliott Coues could list as many as 182 contemporary publications dealing with

11454-476: The hand. The earliest of the new generation of field guides was prepared by Florence Merriam , sister of Clinton Hart Merriam , the mammalogist. This was published in 1887 in a series Hints to Audubon Workers: Fifty Birds and How to Know Them in Grinnell's Audubon Magazine . These were followed by new field guides, from the pioneering illustrated handbooks of Frank Chapman to the classic Field Guide to

11592-513: The hibernation of swallows and little published evidence to contradict the theory. Similar misconceptions existed regarding the breeding of barnacle geese . Their nests had not been seen, and they were believed to grow by transformations of goose barnacles , an idea that became prevalent from around the 11th century and noted by Bishop Giraldus Cambrensis ( Gerald of Wales ) in Topographia Hiberniae (1187). Around 77 AD, Pliny

11730-467: The inconspicuous locations they adopt are an effort to avoid predators and mobbing by small birds. Owls, such as the eagle-owl , will use visual signaling in intraspecific communication (communication within the species), both in territorial habits and parent-offspring interactions. Some researchers believe owls can employ various visual signals in other situations involving intraspecific interaction . Experimental evidence suggests that owl feces and

11868-444: The indigestible parts of their prey (such as bones, scales, and fur) in the form of pellets . These "owl pellets" are plentiful and easy to interpret, and are often sold by companies to schools for dissection by students as a lesson in biology and ecology. Owl eggs typically have a white color and an almost spherical shape, and range in number from a few to a dozen, depending on species and the particular season; for most, three or four

12006-415: The installation of floats. Eyesight is a particular characteristic of the owl that aids in nocturnal prey capture. Owls are part of a small group of birds that live nocturnally, but do not use echolocation to guide them in flight in low-light situations. Owls are known for their disproportionally large eyes in comparison to their skulls. An apparent consequence of the evolution of an absolutely large eye in

12144-439: The introduction of trinomial names. The search for patterns in the variations of birds was attempted by many. Friedrich Wilhelm Joseph Schelling (1775–1854), his student Johann Baptist von Spix (1781–1826), and several others believed that a hidden and innate mathematical order existed in the forms of birds. They believed that a "natural" classification was available and superior to "artificial" ones. A particularly popular idea

12282-476: The labels associated with these early egg collections made them unreliable for the serious study of bird breeding. To preserve eggs, a tiny hole was made and the contents extracted. This technique became standard with the invention of the blow drill around 1830. Egg collection is no longer popular; however, historic museum collections have been of value in determining the effects of pesticides such as DDT on physiology. Museum bird collections continue to act as

12420-534: The laboratory and out in the field, and innovations are constantly made. Most biologists who recognise themselves as "ornithologists" study specific biology research areas, such as anatomy , physiology , taxonomy , ecology , or behaviour . The word "ornithology" comes from the late 16th-century Latin ornithologia meaning "bird science" from the Greek ὄρνις ornis ("bird") and λόγος logos ("theory, science, thought"). The history of ornithology largely reflects

12558-510: The laboratory. For instance, the variation in the ratios of stable hydrogen isotopes across latitudes makes establishing the origins of migrant birds possible using mass spectrometric analysis of feather samples. These techniques can be used in combination with other techniques such as ringing. The first attenuated vaccine developed by Louis Pasteur , for fowl cholera, was tested on poultry in 1878. Anti-malarials were tested on birds which harbour avian-malarias. Poultry continues to be used as

12696-468: The large-sized retinal image. Thus, the primary nocturnal function in the vision of the owl is due to its large posterior nodal distance; retinal image brightness is only maximized to the owl within secondary neural functions. These attributes of the owl cause its nocturnal eyesight to be far superior to that of its average prey. Owls exhibit specialized hearing functions and ear shapes that also aid in hunting. They are noted for asymmetrical ear placements on

12834-439: The largest of any bird's, preventing blood supply from being cut off while they rotate their necks. Other anastomoses between the carotid and vertebral arteries support this effect. The smallest owl—weighing as little as 31 g ( 1 + 3 ⁄ 32  oz) and measuring some 13.5 cm ( 5 + 1 ⁄ 4  in)—is the elf owl ( Micrathene whitneyi ). Around the same diminutive length, although slightly heavier, are

12972-413: The leading edge of owls' remiges muffle an owl's wing beats, allowing an owl's flight to be practically silent. Some fish-eating owls, for which silence has no evolutionary advantage, lack this adaptation. An owl's sharp beak and powerful talons allow it to kill its prey before swallowing it whole (if it is not too big). Scientists studying the diets of owls are helped by their habit of regurgitating

13110-477: The leading edge of the wing, there is a comb of stiff feathers. Second, the trailing edge of the wing contains a flexible fringe. Finally, owls have downy material distributed on the tops of their wings that creates a compliant but rough surface (similar to that of a soft carpet). All these factors result in significant aerodynamic noise reductions. The toes and tarsi are feathered in some species, and more so in species at higher latitudes. Numerous species of owls in

13248-740: The lesser known long-whiskered owlet ( Xenoglaux loweryi ) and Tamaulipas pygmy owl ( Glaucidium sanchezi ). The largest owls are two similarly sized eagle owls ; the Eurasian eagle-owl ( Bubo bubo ) and Blakiston's fish owl ( Bubo blakistoni ). The largest females of these species are 71 cm (28 in) long, have a 190 cm (75 in) wing span, and weigh 4.2 kg ( 9 + 1 ⁄ 4  lb). Different species of owls produce different sounds; this distribution of calls aids owls in finding mates or announcing their presence to potential competitors, and also aids ornithologists and birders in locating these birds and distinguishing species. As noted above, their facial discs help owls to funnel

13386-450: The mosaics of heterogeneous habitats created by fires. This is not to say that all fires are good for owls. Owls only thrive when fires are not of high severity and not large stand-replacing (high-severity fires that burn most of the vegetation) which create large canopy gaps that are not adequate for owls. Avian malaria or Plasmodium relictum affects owls and specifically, 44% of northern and Californian spotted owls harbor 17 strains of

13524-930: The most part seems to have taken place in Eurasia. In the Americas, rather, an expansion of immigrant lineages of ancestral typical owls occurred. The supposed fossil herons "Ardea" perplexa (Middle Miocene of Sansan, France) and "Ardea" lignitum (Late Pliocene of Germany) were more probably owls; the latter was apparently close to the modern genus Bubo . Judging from this, the Late Miocene remains from France described as "Ardea" aureliensis should also be restudied. The Messelasturidae , some of which were initially believed to be basal Strigiformes, are now generally accepted to be diurnal birds of prey showing some convergent evolution toward owls. The taxa often united under Strigogyps were formerly placed in part with

13662-506: The mouse. In addition to hearing, owls have massive eyes relative to their body size. Contrary to popular belief, however, owls cannot see well in extreme dark and are able to see well in the day. Owls are also able to rotate their heads by as much as 270 degrees in either direction without damaging the blood vessels in their necks and heads, and without disrupting blood flow to their brains. Researchers have found four major biological adaptations that allow for this unique capability. First, in

13800-482: The neck higher up than it does in other birds. Instead of going in at the 14th cervical vertebrae, it enters in at the 12th cervical vertebrae. Finally, the small vessel connection between the carotid and the vertebral arteries allow the exchanging of blood between two blood vessels. These cross connections allow for uninterrupted blood flow to the brain. This means that even if one route is blocked during extreme head rotations, another route can continue blood circulation to

13938-460: The neck there is a major artery, called the vertebral artery, that feeds the brain. This artery passes through bony holes in the vertebra. These bony holes are ten times larger in diameter than the artery that passes through them (extra space in the transverse foramina) which creates air pockets that allow for more movement of the artery when twisted. 12 of the 14 cervical vertebrae in the owl's neck have this adaptation. This vertebral artery also enters

14076-485: The nest. Therefore, females may have a larger mass to allow them to go for a longer period of time without starving. For example, one hypothesized sexual role is that larger females are more capable of dismembering prey and feeding it to their young, hence female owls are larger than their male counterparts. A different theory suggests that the size difference between male and females is due to sexual selection: since large females can choose their mate and may violently reject

14214-454: The niche hypothesis and Georgii Gause 's competitive exclusion principle. Work on resource partitioning and the structuring of bird communities through competition were made by Robert MacArthur . Patterns of biodiversity also became a topic of interest. Work on the relationship of the number of species to area and its application in the study of island biogeography was pioneered by E. O. Wilson and Robert MacArthur . These studies led to

14352-463: The oldest indications of an interest in birds. Birds were perhaps important as food sources, and bones of as many as 80 species have been found in excavations of early Stone Age settlements. Waterbird and seabird remains have also been found in shell mounds on the island of Oronsay off the coast of Scotland . Cultures around the world have rich vocabularies related to birds. Traditional bird names are often based on detailed knowledge of

14490-504: The order within the crow family. Where he failed to find five genera, he left a blank insisting that a new genus would be found to fill these gaps. These ideas were replaced by more complex "maps" of affinities in works by Hugh Edwin Strickland and Alfred Russel Wallace . A major advance was made by Max Fürbringer in 1888, who established a comprehensive phylogeny of birds based on anatomy, morphology, distribution, and biology. This

14628-452: The owl's usual prey and also within the owl's own best hearing range. This optimizes the owl's ability to silently fly to capture prey without the prey hearing the owl first as it flies, and to hear any noise the prey makes. It also allows the owl to monitor the sound output from its flight pattern. The disadvantage of such feather adaptations for barn owls is that their feathers are not waterproof. The adaptations mean that barn owls do not use

14766-478: The owls' asymmetrically placed ear cavities. Most birds of prey have eyes on the sides of their heads, but the stereoscopic nature of the owl's forward-facing eyes permits the greater sense of depth perception necessary for low-light hunting. Owls have binocular vision , but they must rotate their entire heads to change the focus of their view because, like most birds, their eyes are fixed in their sockets. Owls are farsighted and cannot clearly see anything nearer than

14904-499: The owls, specifically the Sophiornithidae; they appear to be Ameghinornithidae instead. For fossil species and paleosubspecies of extant taxa , see the genus and species articles. For a full list of extant and recently extinct owls, see the article List of owl species . True owl some 25, see text Striginae sensu Sibley & Ahlquist The true owls or typical owls ( family Strigidae ) are one of

15042-689: The papers in American ornithology journals were written by persons who were not employed in biology related work. Organizations were started in many countries, and these grew rapidly in membership, most notable among them being the Royal Society for the Protection of Birds (RSPB) in Britain and the Audubon Society in the US, which started in 1885. Both these organizations were started with

15180-410: The parasite. As mentioned in the niche competition section above, spotted owls and barred owls are in competition so their niche overlap may be resulting in the plasmodium parasite having more hosts in a concentrated area but this is not certain. The main predators of owls are other species of owls. An example of this occurs with the northern saw-whet owl that lives in the northern U.S. and lives low to

15318-468: The primary objective of conservation. The RSPB, born in 1889, grew from a small Croydon -based group of women, including Eliza Phillips , Etta Lemon , Catherine Hall and Hannah Poland . Calling themselves the "Fur, Fin, and Feather Folk", the group met regularly and took a pledge "to refrain from wearing the feathers of any birds not killed for the purpose of food, the ostrich only exempted." The organization did not allow men as members initially, avenging

15456-448: The rapid decrease in population size of spotted owls will cause a trophic cascade , since the spotted owls help provide a healthy ecosystem . Owls are generally nocturnal and/or crepuscular and spend much of the day roosting . They are often misperceived as ‘tame’ since they allow humans to approach quite closely before taking flight, but in reality they are attempting to avoid detection through stillness. Their cryptic plumage and

15594-505: The relative lengths of wing feathers in warblers) are vital in establishing identity. Captured birds are often marked for future recognition. Rings or bands provide long-lasting identification, but require capture for the information on them to be read. Field-identifiable marks such as coloured bands, wing tags, or dyes enable short-term studies where individual identification is required. Mark and recapture techniques make demographic studies possible. Ringing has traditionally been used in

15732-483: The remains of prey can act as visual signals. This new type of signaling behavior could potentially indicate the owls' current reproductive state to intruders, including other territorial owls or non-breeding floaters. Feces are an ideal material for marking due to its minimal energetic costs, and can also continue to indicate territorial boundaries even when occupied in activities other than territorial defense. Preliminary evidence also suggests that owls will use feces and

15870-425: The same size as their prey. This has also been observed in other predatory birds, which suggests that owls with smaller bodies and long wing chords have been selected for because of the increased agility and speed that allows them to catch their prey. Another popular theory suggests that females have not been selected to be smaller like male owls because of their sexual roles. In many species, female owls may not leave

16008-414: The skull and knead the body. The crushing power of an owl's talons varies according to prey size and type, and by the size of the owl. The burrowing owl ( Athene cunicularia ), a small, partly insectivorous owl, has a release force of only 5 N. The larger barn owl ( Tyto alba ) needs a force of 30 N to release its prey, and one of the largest owls, the great horned owl ( Bubo virginianus ), needs

16146-440: The skull in some genera. Owls can have either internal or external ears, both of which are asymmetrical. Asymmetry has not been reported to extend to the middle or internal ear of the owl. Asymmetrical ear placement on the skull allows the owl to pinpoint the location of its prey. This is especially true for strictly nocturnal species such as the barn owls Tyto or Tengmalm's owl. With ears set at different places on its skull, an owl

16284-463: The sound of prey to their ears. In many species, these discs are placed asymmetrically, for better directional location. Owl plumage is generally cryptic , although several species have facial and head markings, including face masks, ear tufts , and brightly colored irises . These markings are generally more common in species inhabiting open habitats, and are thought to be used in signaling with other owls in low-light conditions. Sexual dimorphism

16422-1032: The specimen "in the hand". The capture and marking of birds enable detailed studies of life history. Techniques for capturing birds are varied and include the use of bird liming for perching birds, mist nets for woodland birds, cannon netting for open-area flocking birds, the bal-chatri trap for raptors, decoys and funnel traps for water birds. The bird in the hand may be examined and measurements can be made, including standard lengths and weights. Feather moult and skull ossification provide indications of age and health. Sex can be determined by examination of anatomy in some sexually nondimorphic species. Blood samples may be drawn to determine hormonal conditions in studies of physiology, identify DNA markers for studying genetics and kinship in studies of breeding biology and phylogeography. Blood may also be used to identify pathogens and arthropod-borne viruses . Ectoparasites may be collected for studies of coevolution and zoonoses . In many cryptic species, measurements (such as

16560-616: The study of living birds was merely recreation held sway until ecological theories became the predominant focus of ornithological studies. The study of birds in their habitats was particularly advanced in Germany with bird ringing stations established as early as 1903. By the 1920s, the Journal für Ornithologie included many papers on the behaviour, ecology, anatomy, and physiology, many written by Erwin Stresemann . Stresemann changed

16698-499: The study of migration. In recent times, satellite transmitters provide the ability to track migrating birds in near-real time. Techniques for estimating population density include point counts , transects , and territory mapping. Observations are made in the field using carefully designed protocols and the data may be analysed to estimate bird diversity, relative abundance, or absolute population densities. These methods may be used repeatedly over large timespans to monitor changes in

16836-418: The torso. This ability keeps bodily movement at a minimum, thus reduces the amount of sound the owl makes as it waits for its prey. Owls are regarded as having the most frontally placed eyes among all avian groups, which gives them some of the largest binocular fields of vision. Owls are farsighted and cannot focus on objects within a few centimetres of their eyes. These mechanisms are only able to function due to

16974-457: The trends in the history of biology , as well as many other scientific disciplines, including ecology , anatomy , physiology , paleontology , and more recently, molecular biology. Trends include the move from mere descriptions to the identification of patterns, thus towards elucidating the processes that produce these patterns. Humans have had an observational relationship with birds since prehistory , with some stone-age drawings being amongst

17112-503: The twilight hours of dawn and dusk; one example is the pygmy owl ( Glaucidium ). A few owls are active during the day, also; examples are the burrowing owl ( Speotyto cunicularia ) and the short-eared owl ( Asio flammeus ). Much of the owls' hunting strategy depends on stealth and surprise. Owls have at least two adaptations that aid them in achieving stealth. First, the dull coloration of their feathers can render them almost invisible under certain conditions. Secondly, serrated edges on

17250-415: The two generally accepted families of owls , the other being the barn owls (Tytonidae). This large family comprises 230 living or recently extinct species in 24 genera . The Strigidae owls have a cosmopolitan distribution and are found on every continent except Antarctica . While typical owls (hereafter referred to simply as owls) vary greatly in size, with the smallest species, the elf owl , being

17388-1084: The widespread interest in birds, use of a large number of people to work on collaborative ornithological projects that cover large geographic scales has been possible. These citizen science projects include nationwide projects such as the Christmas Bird Count , Backyard Bird Count, the North American Breeding Bird Survey , the Canadian EPOQ or regional projects such as the Asian Waterfowl Census and Spring Alive in Europe. These projects help to identify distributions of birds, their population densities and changes over time, arrival and departure dates of migration, breeding seasonality, and even population genetics. The results of many of these projects are published as bird atlases . Studies of migration using bird ringing or colour marking often involve

17526-463: The word ecology appeared in 1915. The Ibis , however, resisted the introduction of these new methods of study, and no paper on ecology appeared until 1943. The work of David Lack on population ecology was pioneering. Newer quantitative approaches were introduced for the study of ecology and behaviour, and this was not readily accepted. For instance, Claud Ticehurst wrote: Sometimes it seems that elaborate plans and statistics are made to prove what

17664-566: The works of ancient writers from Greek and Syriac . In the 12th and 13th centuries, crusades and conquest had subjugated Islamic territories in southern Italy, central Spain, and the Levant under European rule, and for the first time translations into Latin of the great works of Arabic and Greek scholars were made with the help of Jewish and Muslim scholars, especially in Toledo , which had fallen into Christian hands in 1085 and whose libraries had escaped destruction. Michael Scotus from Scotland made

17802-405: The world and across a multitude of ecosystems, their hunting skills and characteristics vary slightly from species to species, though most characteristics are shared among all species. Most owls share an innate ability to fly almost silently and also more slowly in comparison to other birds of prey. Most owls live a mainly nocturnal lifestyle and being able to fly without making any noise gives them

17940-576: The world. Artificial incubation of poultry was practised in China around 246 BC and around at least 400 BC in Egypt. The Egyptians also made use of birds in their hieroglyphic scripts, many of which, though stylized, are still identifiable to species. Early written records provide valuable information on the past distributions of species. For instance, Xenophon records the abundance of the ostrich in Assyria (Anabasis, i. 5); this subspecies from Asia Minor

18078-446: Was also due in part to colonialism . At 100 years later, in 1959, R. E. Moreau noted that ornithology in this period was preoccupied with the geographical distributions of various species of birds. No doubt the preoccupation with widely extended geographical ornithology, was fostered by the immensity of the areas over which British rule or influence stretched during the 19th century and for some time afterwards. The bird collectors of

18216-400: Was developed further by Hans Gadow and others. The Galapagos finches were especially influential in the development of Charles Darwin 's theory of evolution. His contemporary Alfred Russel Wallace also noted these variations and the geographical separations between different forms leading to the study of biogeography . Wallace was influenced by the work of Philip Lutley Sclater on

18354-706: Was involved in establishing Gaetz Lakes bird sanctuary. In the United States, the Breeding Bird Surveys , conducted by the United States Geological Survey , have also produced atlases with information on breeding densities and changes in the density and distribution over time. Other volunteer collaborative ornithology projects were subsequently established in other parts of the world. The tools and techniques of ornithology are varied, and new inventions and approaches are quickly incorporated. The techniques may be broadly dealt under

18492-491: Was part of Ibn Sīnā's massive Kitāb al-Šifāʾ . Frederick II eventually wrote his own treatise on falconry, the De arte venandi cum avibus , in which he related his ornithological observations and the results of the hunts and experiments his court enjoyed performing. Several early German and French scholars compiled old works and conducted new research on birds. These included Guillaume Rondelet , who described his observations in

18630-668: Was pioneered by Charles Sibley and Jon Edward Ahlquist , resulting in what is called the Sibley–Ahlquist taxonomy . These early techniques have been replaced by newer ones based on mitochondrial DNA sequences and molecular phylogenetics approaches that make use of computational procedures for sequence alignment , construction of phylogenetic trees , and calibration of molecular clocks to infer evolutionary relationships. Molecular techniques are also widely used in studies of avian population biology and ecology. The use of field glasses or telescopes for bird observation began in

18768-535: Was the Quinarian system popularised by Nicholas Aylward Vigors (1785–1840), William Sharp Macleay (1792–1865), William Swainson , and others. The idea was that nature followed a "rule of five" with five groups nested hierarchically. Some had attempted a rule of four, but Johann Jakob Kaup (1803–1873) insisted that the number five was special, noting that other natural entities such as the senses also came in fives. He followed this idea and demonstrated his view of

18906-426: Was used to interpret observations on behaviour and life history, and birds were widely used models for testing hypotheses based on theories postulated by W. D. Hamilton and others. The new tools of molecular biology changed the study of bird systematics, which changed from being based on phenotype to the underlying genotype . The use of techniques such as DNA–DNA hybridization to study evolutionary relationships

19044-436: Was written by Christopher Merrett in 1667, but authors such as John Ray considered it of little value. Ray did, however, value the expertise of the naturalist Sir Thomas Browne (1605–82), who not only answered his queries on ornithological identification and nomenclature, but also those of Willoughby and Merrett in letter correspondence. Browne himself in his lifetime kept an eagle, owl, cormorant, bittern, and ostrich, penned

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