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93-445: There is a strong avian presence on the islands, and hunting is prohibited. Species include Cory's shearwater ( Calonectris diomedea ) and migratory passerines . There is also a large spring migration of turtle doves ( Streptopelia turtur ). The islands have been recognised as an Important Bird Area (IBA) by BirdLife International because they support a breeding population of some 2,000-3,000 pairs of Scopoli's shearwaters . As

186-442: A follicle in the skin . The basal part of the calamus is without vanes. This part is embedded within the skin follicle and has an opening at the base (proximal umbilicus) and a small opening on the side (distal umbilicus). Hatchling birds of some species have a special kind of natal down feathers (neossoptiles) which are pushed out when the normal feathers (teleoptiles) emerge. Flight feathers are stiffened so as to work against

279-727: A better sense of smell. A third stage of bird evolution starting with Ornithothoraces (the "bird-chested" avialans) can be associated with the refining of aerodynamics and flight capabilities, and the loss or co-ossification of several skeletal features. Particularly significant are the development of an enlarged, keeled sternum and the alula , and the loss of grasping hands. † Anchiornis † Archaeopteryx † Xiaotingia † Rahonavis † Jeholornis † Jixiangornis † Balaur † Zhongjianornis † Sapeornis † Confuciusornithiformes † Protopteryx † Pengornis Ornithothoraces † Enantiornithes Feather Feathers are epidermal growths that form

372-432: A bird's head, neck and trunk. Filoplumes are entirely absent in ratites . In some passerines, filoplumes arise exposed beyond the pennaceous feathers on the neck. The remiges, or flight feathers of the wing, and rectrices, or flight feathers of the tail, are the most important feathers for flight. A typical vaned feather features a main shaft, called the rachis . Fused to the rachis are a series of branches, or barbs ;

465-473: A definition similar to "all theropods closer to birds than to Deinonychus ", with Troodon being sometimes added as a second external specifier in case it is closer to birds than to Deinonychus . Avialae is also occasionally defined as an apomorphy-based clade (that is, one based on physical characteristics). Jacques Gauthier , who named Avialae in 1986, re-defined it in 2001 as all dinosaurs that possessed feathered wings used in flapping flight , and

558-451: A distinctive outer covering, or plumage , on both avian (bird) and some non-avian dinosaurs and other archosaurs . They are the most complex integumentary structures found in vertebrates and an example of a complex evolutionary novelty. They are among the characteristics that distinguish the extant birds from other living groups. Although feathers cover most of the bird's body, they arise only from certain well-defined tracts on

651-442: A group called Paraves . Some basal members of Deinonychosauria, such as Microraptor , have features which may have enabled them to glide or fly. The most basal deinonychosaurs were very small. This evidence raises the possibility that the ancestor of all paravians may have been arboreal , have been able to glide, or both. Unlike Archaeopteryx and the non-avialan feathered dinosaurs, who primarily ate meat, studies suggest that

744-634: A group of warm-blooded vertebrates constituting the class Aves ( Latin: [ˈaveːs] ), characterised by feathers , toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart , and a strong yet lightweight skeleton . Birds live worldwide and range in size from the 5.5 cm (2.2 in) bee hummingbird to the 2.8 m (9 ft 2 in) common ostrich . There are over 11,000 living species and they are split into 44 orders . More than half are passerine or "perching" birds. Birds have wings whose development varies according to species;

837-449: A large rachis but few barbs. Rictal bristles are found around the eyes and bill. They may serve a similar purpose to eyelashes and vibrissae in mammals . Although there is as yet no clear evidence, it has been suggested that rictal bristles have sensory functions and may help insectivorous birds to capture prey. In one study, willow flycatchers ( Empidonax traillii ) were found to catch insects equally well before and after removal of

930-467: A meal. As with fish, the top and bottom colors may be different, in order to provide camouflage during flight. Striking differences in feather patterns and colors are part of the sexual dimorphism of many bird species and are particularly important in the selection of mating pairs. In some cases, there are differences in the UV reflectivity of feathers across sexes even though no differences in color are noted in

1023-559: A means for determining the evolutionary relationships of bird families. Species that incubate their own eggs often lose their feathers on a region of their belly, forming a brooding patch . The colors of feathers are produced by pigments, by microscopic structures that can refract , reflect, or scatter selected wavelengths of light, or by a combination of both. Most feather pigments are melanins (brown and beige pheomelanins , black and grey eumelanins ) and carotenoids (red, yellow, orange); other pigments occur only in certain taxa –

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1116-544: A number of industrial applications as a medium for culturing microbes, biodegradable polymers, and production of enzymes. Feather proteins have been tried as an adhesive for wood board. Some groups of Native people in Alaska have used ptarmigan feathers as temper (non-plastic additives) in pottery manufacture since the first millennium BC in order to promote thermal shock resistance and strength. Eagle feathers have great cultural and spiritual value to Native Americans in

1209-462: A pennibrachium (a wing-like structure consisting of elongate feathers), while younger ones did not. This suggests that the pennibrachium was a secondary sex characteristic and likely had a sexual function. Several genes have been found to determine feather development. They will be key to understand the evolution of feathers. For instance, some genes convert scales into feathers or feather-like structures when expressed or induced in bird feet, such as

1302-710: A popular trend as a hairstyle accessory, with feathers formerly used as fishing lures now being used to provide color and style to hair. Feather products manufacturing in Europe has declined in the last 60 years, mainly due to competition from Asia. Feathers have adorned hats at many prestigious events such as weddings and Ladies Day at racecourses (Royal Ascot). The functional view on the evolution of feathers has traditionally focused on insulation, flight and display. Discoveries of non-flying Late Cretaceous feathered dinosaurs in China, however, suggest that flight could not have been

1395-450: A powder puff to apply the powder. Waterproofing can be lost by exposure to emulsifying agents due to human pollution. Feathers can then become waterlogged, causing the bird to sink. It is also very difficult to clean and rescue birds whose feathers have been fouled by oil spills . The feathers of cormorants soak up water and help to reduce buoyancy, thereby allowing the birds to swim submerged. Bristles are stiff, tapering feathers with

1488-436: A role in the evolution of powered flight. The coloration of feathers is believed to have evolved primarily in response to sexual selection . In fossil specimens of the paravian Anchiornis huxleyi and the pterosaur Tupandactylus imperator , the features are so well preserved that the melanosome (pigment cells) structure can be observed. By comparing the shape of the fossil melanosomes to melanosomes from extant birds,

1581-406: A sister group, the order Crocodilia , contain the only living representatives of the reptile clade Archosauria . During the late 1990s, Aves was most commonly defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica . However, an earlier definition proposed by Jacques Gauthier gained wide currency in the 21st century, and

1674-717: A time, sometimes for years, and rarely for life. Other species have breeding systems that are polygynous (one male with many females) or, rarely, polyandrous (one female with many males). Birds produce offspring by laying eggs which are fertilised through sexual reproduction . They are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching. Many species of birds are economically important as food for human consumption and raw material in manufacturing, with domesticated and undomesticated birds being important sources of eggs, meat, and feathers. Songbirds , parrots, and other species are popular as pets. Guano (bird excrement)

1767-711: A waste product of poultry farming, including chickens , geese , turkeys , pheasants , and ostriches . These feathers are dyed and manipulated to enhance their appearance, as poultry feathers are naturally often dull in appearance compared to the feathers of wild birds. Feather derives from the Old English "feþer", which is of Germanic origin; related to Dutch "veer" and German "Feder", from an Indo-European root shared by Sanskrit's "patra" meaning 'wing', Latin's "penna" meaning 'feather', and Greek's "pteron", "pterux" meaning 'wing'. Because of feathers being an integral part of quills , which were early pens used for writing,

1860-427: A waterproofing agent and a feather conditioner . Powder down has evolved independently in several taxa and can be found in down as well as in pennaceous feathers. They may be scattered in plumage as in the pigeons and parrots or in localized patches on the breast, belly, or flanks, as in herons and frogmouths. Herons use their bill to break the powder down feathers and to spread them, while cockatoos may use their head as

1953-402: Is actually more closely related to Ornithischia , to which it formed the sister group within the clade Ornithoscelida . The study also suggested that if the feather-like structures of theropods and ornithischians are of common evolutionary origin then it would be possible that feathers were restricted to Ornithoscelida. If so, then the origin of feathers would have likely occurred as early as

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2046-540: Is called ornithology . Birds are feathered theropod dinosaurs and constitute the only known living dinosaurs . Likewise, birds are considered reptiles in the modern cladistic sense of the term, and their closest living relatives are the crocodilians . Birds are descendants of the primitive avialans (whose members include Archaeopteryx ) which first appeared during the Late Jurassic . According to recent estimates, modern birds ( Neornithes ) evolved in

2139-506: Is called by some the Dyck texture. Melanin is often involved in the absorption of light; in combination with a yellow pigment, it produces a dull olive-green. In some birds, feather colors may be created, or altered, by secretions from the uropygial gland , also called the preen gland. The yellow bill colors of many hornbills are produced by such secretions. It has been suggested that there are other color differences that may be visible only in

2232-408: Is caused by defective pigment production, though structural coloration will not be affected (as can be seen, for example, in blue-and-white budgerigars ). The blues and bright greens of many parrots are produced by constructive interference of light reflecting from different layers of structures in feathers. In the case of green plumage, in addition to yellow, the specific feather structure involved

2325-568: Is considered presumptuous. During the 18th, 19th, and early 20th centuries, there was a booming international trade in plumes for extravagant women's hats and other headgear (including in Victorian fashion ). Frank Chapman noted in 1886 that feathers of as many as 40 species of birds were used in about three-fourths of the 700 ladies' hats that he observed in New York City. For instance, South American hummingbird feathers were used in

2418-429: Is harvested for use as a fertiliser. Birds figure throughout human culture. About 120 to 130 species have become extinct due to human activity since the 17th century, and hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry. The first classification of birds

2511-449: Is in a precarious state. Κουτελάκης Χαρ., Η «Οδύσσεια» του Ομήρου χωρίς Λαιστρυγόνες και τέρατα. Μια νέα προσέγγιση για την ανθρωπογεωγραφία της Μεσογείου, Αθήνα 30 Δεκ. 2019, σελ. 235-236. Κουτελάκης Χαρ., Παναγιά «Η Πάντων Χαρά» των Στροφάδων. Ένα εικονογραφικό παράλληλο στην Πάτμο, ΔωδΧρον. ΙΕ΄ (1993) 67-79. 37°15′N 21°00′E  /  37.250°N 21.000°E  / 37.250; 21.000 Bird Birds are

2604-427: Is likely that non-avian dinosaur species utilized plumage patterns for similar functions as modern birds before the origin of flight. In many cases, the physiological condition of the birds (especially males) is indicated by the quality of their feathers, and this is used (by the females) in mate choice . Additionally, when comparing different Ornithomimus edmontonicus specimens, older individuals were found to have

2697-503: Is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor. Over 40% of key traits found in modern birds evolved during the 60 million year transition from the earliest bird-line archosaurs to the first maniraptoromorphs , i.e. the first dinosaurs closer to living birds than to Tyrannosaurus rex . The loss of osteoderms otherwise common in archosaurs and acquisition of primitive feathers might have occurred early during this phase. After

2790-542: Is suppressed during embryological development of the alligator and so is not present in the scales of mature alligators. The presence of this homologous keratin in both birds and crocodilians indicates that it was inherited from a common ancestor. This may suggest that crocodilian scales, bird and dinosaur feathers, and pterosaur pycnofibres are all developmental expressions of the same primitive archosaur skin structures; suggesting that feathers and pycnofibers could be homologous. Molecular dating methods in 2011 show that

2883-516: Is synonymous to Avifilopluma. † Scansoriopterygidae † Eosinopteryx † Jinfengopteryx † Aurornis † Dromaeosauridae † Troodontidae Avialae Based on fossil and biological evidence, most scientists accept that birds are a specialised subgroup of theropod dinosaurs and, more specifically, members of Maniraptora , a group of theropods which includes dromaeosaurids and oviraptorosaurs , among others. As scientists have discovered more theropods closely related to birds,

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2976-535: Is used by many scientists including adherents to the PhyloCode . Gauthier defined Aves to include only the crown group of the set of modern birds. This was done by excluding most groups known only from fossils , and assigning them, instead, to the broader group Avialae, on the principle that a clade based on extant species should be limited to those extant species and their closest extinct relatives. Gauthier and de Queiroz identified four different definitions for

3069-609: The Argonauts . Zetes and Calaïs rescued Phineus from the Harpies. They succeeded in driving the monsters away but did not kill them, as a request from the goddess of the rainbow, Iris , who promised that Phineas would not be bothered by the Harpies again. They were turned back at the Strophades by Iris while continuing their pursuit of the creatures. It is a popular etymology based on word similarities. Stormy winds prevailed on

3162-479: The Indian peacock have been used in traditional medicine for snakebite, infertility, and coughs. Members of Scotland's Clan Campbell are known to wear feathers on their bonnets to signify authority within the clan. Clan chiefs wear three, chieftains wear two and an armiger wears one. Any member of the clan who does not meet the criteria is not authorized to wear feathers as part of traditional garb and doing so

3255-722: The Late Cretaceous and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 million years ago, which killed off the pterosaurs and all non- ornithuran dinosaurs. Many social species preserve knowledge across generations ( culture ). Birds are social, communicating with visual signals, calls, and songs , and participating in such behaviour as cooperative breeding and hunting, flocking , and mobbing of predators. The vast majority of bird species are socially (but not necessarily sexually) monogamous , usually for one breeding season at

3348-471: The Middle Triassic , though this has been disagreed upon. The lack of feathers present in large sauropods and ankylosaurs could be that feathers were suppressed by genomic regulators. Several studies of feather development in the embryos of modern birds, coupled with the distribution of feather types among various prehistoric bird precursors, have allowed scientists to attempt a reconstruction of

3441-669: The Tiaojishan Formation of China, which has been dated to the late Jurassic period ( Oxfordian stage), about 160 million years ago. The avialan species from this time period include Anchiornis huxleyi , Xiaotingia zhengi , and Aurornis xui . The well-known probable early avialan, Archaeopteryx , dates from slightly later Jurassic rocks (about 155 million years old) from Germany . Many of these early avialans shared unusual anatomical features that may be ancestral to modern birds but were later lost during bird evolution. These features include enlarged claws on

3534-627: The United States and First Nations peoples in Canada as religious objects. In the United States, the religious use of eagle and hawk feathers is governed by the eagle feather law , a federal law limiting the possession of eagle feathers to certified and enrolled members of federally recognized Native American tribes. In South America, brews made from the feathers of condors are used in traditional medications. In India, feathers of

3627-494: The ornithischian dinosaurs Tianyulong and Psittacosaurus . The exact nature of these structures is still under study. However, it is believed that the stage-1 feathers (see Evolutionary stages section below) such as those seen in these two ornithischians likely functioned in display. In 2014, the ornithischian Kulindadromeus was reported as having structures resembling stage-3 feathers. The likelihood of scales evolving on early dinosaur ancestors are high. However, this

3720-401: The penguins , ratites and screamers. In most birds the feathers grow from specific tracts of skin called pterylae ; between the pterylae there are regions which are free of feathers called apterylae (or apteria ). Filoplumes and down may arise from the apterylae. The arrangement of these feather tracts, pterylosis or pterylography, varies across bird families and has been used in the past as

3813-401: The α-keratins of mammalian hair , horns and hooves . The exact signals that induce the growth of feathers on the skin are not known, but it has been found that the transcription factor cDermo-1 induces the growth of feathers on skin and scales on the leg. There are two basic types of feather: vaned feathers which cover the exterior of the body, and down feathers which are underneath

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3906-847: The Strophades, they were identified as the dwelling-place of the Harpies . Virgil states that the Harpy drove the Trojans from the Strophades ( Aeneid iii, 209 passim. ). The islands are mentioned in The Divine Comedy (see List of cultural references in The Divine Comedy ) and in passing in Chapter 10 of Rabelais ' Fifth Book of Pantagruel . According to legend, the islands' name, meaning "Islands of Turning," refers to Zetes and Calaïs , sons of Boreas , who voyaged with

3999-451: The ability to expand from a compressed, stored state to trap large amounts of compartmentalized, insulating air. Feathers of large birds (most often geese ) have been and are used to make quill pens. Historically, the hunting of birds for decorative and ornamental feathers has endangered some species and helped to contribute to the extinction of others. Today, feathers used in fashion and in military headdresses and clothes are obtained as

4092-445: The air in the downstroke but yield in other directions. It has been observed that the orientation pattern of β-keratin fibers in the feathers of flying birds differs from that in flightless birds: the fibers are better aligned along the shaft axis direction towards the tip, and the lateral walls of rachis region show structure of crossed fibers. Feathers insulate birds from water and cold temperatures. They may also be plucked to line

4185-416: The ancestral state of dinosaurs. In 2010, a carcharodontosaurid named Concavenator corcovatus was found to have remiges on the ulna suggesting it might have had quill-like structures on the ams. However, Foth et al. 2014 disagress with the publication where they point out that the bumps on the ulna of Concavenator are on the anterolateral which is unlike remiges which are in a posterolateral on

4278-428: The appearance of Maniraptoromorpha, the next 40 million years marked a continuous reduction of body size and the accumulation of neotenic (juvenile-like) characteristics. Hypercarnivory became increasingly less common while braincases enlarged and forelimbs became longer. The integument evolved into complex, pennaceous feathers . The oldest known paravian (and probably the earliest avialan) fossils come from

4371-421: The barbs themselves are also branched and form the barbules . These barbules have minute hooks called barbicels for cross-attachment. Down feathers are fluffy because they lack barbicels, so the barbules float free of each other, allowing the down to trap air and provide excellent thermal insulation. At the base of the feather, the rachis expands to form the hollow tubular calamus (or quill ) which inserts into

4464-509: The birds that descended from them. Despite being currently one of the most widely used, the crown-group definition of Aves has been criticised by some researchers. Lee and Spencer (1997) argued that, contrary to what Gauthier defended, this definition would not increase the stability of the clade and the exact content of Aves will always be uncertain because any defined clade (either crown or not) will have few synapomorphies distinguishing it from its closest relatives. Their alternative definition

4557-399: The color and pattern of the feathers on Anchiornis and Tupandactylus could be determined. Anchiornis was found to have black-and-white-patterned feathers on the forelimbs and hindlimbs, with a reddish-brown crest. This pattern is similar to the coloration of many extant bird species, which use plumage coloration for display and communication, including sexual selection and camouflage. It

4650-421: The darker birds confirmed Gloger's rule . Although sexual selection plays a major role in the development of feathers, in particular, the color of the feathers it is not the only conclusion available. New studies are suggesting that the unique feathers of birds are also a large influence on many important aspects of avian behavior, such as the height at which different species build their nests. Since females are

4743-665: The earliest members of Aves, is removed from this group, becoming a non-avian dinosaur instead. These proposals have been adopted by many researchers in the field of palaeontology and bird evolution , though the exact definitions applied have been inconsistent. Avialae, initially proposed to replace the traditional fossil content of Aves, is often used synonymously with the vernacular term "bird" by these researchers. † Coelurus † Ornitholestes † Ornithomimosauria † Alvarezsauridae † Oviraptorosauria   Paraves Most researchers define Avialae as branch-based clade, though definitions vary. Many authors have used

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4836-490: The evolution of feathers—theropods with highly derived bird-like characteristics occurred at a later time than Archaeopteryx —suggesting that the descendants of birds arose before the ancestor. However, the discovery of Anchiornis huxleyi in the Late Jurassic Tiaojishan Formation (160 MYA) in western Liaoning in 2009 resolved this paradox. By predating Archaeopteryx , Anchiornis proves

4929-614: The evolution of proto-birds like Archaeopteryx and Microraptor zhaoianus . Another theory posits that the original adaptive advantage of early feathers was their pigmentation or iridescence, contributing to sexual preference in mate selection. Dinosaurs that had feathers or protofeathers include Pedopenna daohugouensis and Dilong paradoxus , a tyrannosauroid which is 60 to 70 million years older than Tyrannosaurus rex . The majority of dinosaurs known to have had feathers or protofeathers are theropods , however featherlike "filamentous integumentary structures" are also known from

5022-512: The existence of a modernly feathered theropod ancestor, providing insight into the dinosaur-bird transition. The specimen shows distribution of large pennaceous feathers on the forelimbs and tail, implying that pennaceous feathers spread to the rest of the body at an earlier stage in theropod evolution. The development of pennaceous feathers did not replace earlier filamentous feathers. Filamentous feathers are preserved alongside modern-looking flight feathers – including some with modifications found in

5115-538: The expense of health. A bird's feathers undergo wear and tear and are replaced periodically during the bird's life through molting . New feathers, known when developing as blood, or pin feathers , depending on the stage of growth, are formed through the same follicles from which the old ones were fledged. The presence of melanin in feathers increases their resistance to abrasion. One study notes that melanin based feathers were observed to degrade more quickly under bacterial action, even compared to unpigmented feathers from

5208-419: The face that were used as tactile sensors. While feathers have been suggested as having evolved from reptilian scales , there are numerous objections to that idea, and more recent explanations have arisen from the paradigm of evolutionary developmental biology . Theories of the scale-based origins of feathers suggest that the planar scale structure was modified for development into feathers by splitting to form

5301-411: The feathers of extant diving birds – in 80 million year old amber from Alberta. Two small wings trapped in amber dating to 100 mya show plumage existed in some bird predecessors. The wings most probably belonged to enantiornithes , a diverse group of avian dinosaurs. A large phylogenetic analysis of early dinosaurs by Matthew Baron, David B. Norman and Paul Barrett (2017) found that Theropoda

5394-451: The first avialans were omnivores . The Late Jurassic Archaeopteryx is well known as one of the first transitional fossils to be found, and it provided support for the theory of evolution in the late 19th century. Archaeopteryx was the first fossil to display both clearly traditional reptilian characteristics—teeth, clawed fingers, and a long, lizard-like tail—as well as wings with flight feathers similar to those of modern birds. It

5487-417: The gate today). The last monk to inhabit the monastery was Father Grigorios, who settled there in 1976. The only other inhabitant of the island at the time was the lighthouse keeper, but in 1985 the lighthouse became automated, leaving him alone. On the 18th of November 1997, a magnitude 6.6 earthquake struck the island, causing severe damage to the historic monastery. This was the only time that Grigorios fled

5580-427: The identification of species in forensic studies, particularly in bird strikes to aircraft. The ratios of hydrogen isotopes in feathers help in determining the geographic origins of birds. Feathers may also be useful in the non-destructive sampling of pollutants. The poultry industry produces a large amount of feathers as waste, which, like other forms of keratin, are slow to decompose. Feather waste has been used in

5673-476: The island after a shipwreck. The monastery is built similarly to a fortress and survived raids from pirates through the centuries. In the past many monks lived in the monastery, among them Dionysios of Zakynthos (patron saint of Zakynthos , who died in 1622). In 1717, the Ottomans attacked the fortress, a Deacon supposedly killed 18 Turks (the parapets had cannons on them, two of which are still in existence at

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5766-545: The island at times, in the form of a tornado, which the ancients used to identify with the phrase "στροφάδες άελλαι". This is confirmed by the names of the two main winds, the north (Ziti) and the south (Kalai). The monastery of the Blessed Mother of God on Stamfani island, was built in 1241 at the request of Princess Irene Laskarina (daughter of the Nicaean Emperor Theodore I ) who survived on

5859-520: The island for several days, though he returned to attempt to rebuild. Father Grigorios was forced to leave the island due to ill health in 2014 and retired to his home village of Agalas , Zakynthos, where he died in 2017. There is a modern sculpture monument at the monastery, which commemorates the many monks who were killed in Turkish raids. Currently, the monastery buildings are in a state of some disrepair, mainly due to earthquake damage. The main tower

5952-483: The nest and provide insulation to the eggs and young. The individual feathers in the wings and tail play important roles in controlling flight. Some species have a crest of feathers on their heads. Although feathers are light, a bird's plumage weighs two or three times more than its skeleton, since many bones are hollow and contain air sacs. Color patterns serve as camouflage against predators for birds in their habitats, and serve as camouflage for predators looking for

6045-582: The nest. The height study found that birds that nest in the canopies of trees often have many more predator attacks due to the brighter color of feathers that the female displays. Another influence of evolution that could play a part in why feathers of birds are so colorful and display so many patterns could be due to that birds developed their bright colors from the vegetation and flowers that thrive around them. Birds develop their bright colors from living around certain colors. Most bird species often blend into their environment, due to some degree of camouflage, so if

6138-621: The nests of other species also have host-specific feather lice and these seem to be transmitted only after the young cuckoos leave the host nest. Birds maintain their feather condition by preening and bathing in water or dust . It has been suggested that a peculiar behavior of birds, anting , in which ants are introduced into the plumage, helps to reduce parasites, but no supporting evidence has been found. Bird feathers have long been used for fletching arrows . Colorful feathers such as those belonging to pheasants have been used to decorate fishing lures . Feathers are also valuable in aiding

6231-523: The only known groups without wings are the extinct moa and elephant birds . Wings, which are modified forelimbs , gave birds the ability to fly, although further evolution has led to the loss of flight in some birds , including ratites , penguins , and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds , have further evolved for swimming. The study of birds

6324-462: The original primary function as the feathers simply would not have been capable of providing any form of lift. There have been suggestions that feathers may have had their original function in thermoregulation, waterproofing, or even as sinks for metabolic wastes such as sulphur. Recent discoveries are argued to support a thermoregulatory function, at least in smaller dinosaurs. Some researchers even argue that thermoregulation arose from bristles on

6417-402: The outermost half) can be seen in the evolution of maniraptoromorphs, and this process culminated in the appearance of the pygostyle , an ossification of fused tail vertebrae. In the late Cretaceous, about 100 million years ago, the ancestors of all modern birds evolved a more open pelvis, allowing them to lay larger eggs compared to body size. Around 95 million years ago, they evolved

6510-463: The parasite species being specific to the host and coevolving with the host, making them of interest in phylogenetic studies. Feather holes are chewing traces of lice (most probably Brueelia spp. lice) on the wing and tail feathers. They were described on barn swallows , and because of easy countability, many evolutionary, ecological, and behavioral publications use them to quantify the intensity of infestation. Parasitic cuckoos which grow up in

6603-492: The past to dress some of the miniature birds featured in singing bird boxes . This trade caused severe losses to bird populations (for example, egrets and whooping cranes ). Conservationists led a major campaign against the use of feathers in hats. This contributed to passage of the Lacey Act in 1900, and to changes in fashion. The ornamental feather market then largely collapsed. More recently, rooster plumage has become

6696-536: The previously clear distinction between non-birds and birds has become blurred. By the 2000s, discoveries in the Liaoning Province of northeast China, which demonstrated many small theropod feathered dinosaurs , contributed to this ambiguity. The consensus view in contemporary palaeontology is that the flying theropods, or avialans , are the closest relatives of the deinonychosaurs , which include dromaeosaurids and troodontids . Together, these form

6789-432: The prime caregivers, evolution has helped select females to display duller colors down so that they may blend into the nesting environment. The position of the nest and whether it has a greater chance of being under predation has exerted constraints on female birds' plumage. A species of bird that nests on the ground, rather than the canopy of the trees, will need to have much duller colors in order not to attract attention to

6882-466: The rachis and herringbone pattern of the barbs. In the clade Deinonychosauria, the continued divergence of feathers is also apparent in the families Troodontidae and Dromaeosauridae . Branched feathers with rachis, barbs, and barbules were discovered in many members including Sinornithosaurus millenii , a dromaeosaurid found in the Yixian formation (124.6 MYA). Previously, a temporal paradox existed in

6975-654: The recent common ancestors of birds, Oviraptorosauria and Deinonychosauria . In 1998, the discovery of a feathered oviraptorosaurian, Caudipteryx zoui , challenged the notion of feathers as a structure exclusive to Avialae. Buried in the Yixian Formation in Liaoning, China, C. zoui lived during the Early Cretaceous Period. Present on the forelimbs and tails, their integumentary structure has been accepted as pennaceous vaned feathers based on

7068-412: The rictal bristles. Grebes are peculiar in their habit of ingesting their own feathers and feeding them to their young. Observations on their diet of fish and the frequency of feather eating suggest that ingesting feathers, particularly down from their flanks, aids in forming easily ejectable pellets. Contour feathers are not uniformly distributed on the skin of the bird except in some groups such as

7161-452: The same biological name "Aves", which is a problem. The authors proposed to reserve the term Aves only for the crown group consisting of the last common ancestor of all living birds and all of its descendants, which corresponds to meaning number 4 below. They assigned other names to the other groups.   Lizards & snakes   Turtles   Crocodiles   Birds Under the fourth definition Archaeopteryx , traditionally considered one of

7254-413: The same species, than those unpigmented or with carotenoid pigments. However, another study the same year compared the action of bacteria on pigmentations of two song sparrow species and observed that the darker pigmented feathers were more resistant; the authors cited other research also published in 2004 that stated increased melanin provided greater resistance. They observed that the greater resistance of

7347-433: The scale-feather converters Sox2 , Zic1 , Grem1 , Spry2 , and Sox18 . Feathers and scales are made up of two distinct forms of keratin , and it was long thought that each type of keratin was exclusive to each skin structure (feathers and scales). However, feather keratin is also present in the early stages of development of American alligator scales. This type of keratin, previously thought to be specific to feathers,

7440-551: The second toe which may have been held clear of the ground in life, and long feathers or "hind wings" covering the hind limbs and feet, which may have been used in aerial maneuvering. Avialans diversified into a wide variety of forms during the Cretaceous period. Many groups retained primitive characteristics , such as clawed wings and teeth, though the latter were lost independently in a number of avialan groups, including modern birds (Aves). Increasingly stiff tails (especially

7533-612: The skin. They aid in flight, thermal insulation, and waterproofing. In addition, coloration helps in communication and protection . The study of feathers is called plumology (or plumage science ). People use feathers in many ways that are practical, cultural, and religious. Feathers are both soft and excellent at trapping heat ; thus, they are sometimes used in high-class bedding , especially pillows , blankets , and mattresses . They are also used as filling for winter clothing and outdoor bedding, such as quilted coats and sleeping bags . Goose and eider down have great loft ,

7626-535: The species habitat is full of colors and patterns, the species would eventually evolve to blend in to avoid being eaten. Birds' feathers show a large range of colors, even exceeding the variety of many plants, leaf, and flower colors. The feather surface is the home for some ectoparasites, notably feather lice ( Phthiraptera ) and feather mites. Feather lice typically live on a single host and can move only from parents to chicks, between mating birds, and, occasionally, by phoresy . This life history has resulted in most of

7719-467: The subfamily of feather β-keratins found in extant birds started to diverge 143 million years ago, suggesting the pennaceous feathers of Anchiornis were not made of the feather β-keratins present in extant birds. However, a study of fossil feathers from the dinosaur Sinosauropteryx and other fossils revealed traces of beta-sheet proteins, using infrared spectroscopy and sulfur-X-ray spectroscopy. The presence of abundant alpha-proteins in some fossil feathers

7812-412: The ulna of some birds, they consider it more likely that these are attachments for interosseous ligaments. This was refuted by Cuesta Fidalgo and her colleagues, they pointed out that these bumps on the ulna are posterolateral which is unlike that of interosseous ligaments. Since the 1990s, dozens of feathered dinosaurs have been discovered in the clade Maniraptora , which includes the clade Avialae and

7905-497: The ultraviolet region, but studies have failed to find evidence. The oil secretion from the uropygial gland may also have an inhibitory effect on feather bacteria. The reds, orange and yellow colors of many feathers are caused by various carotenoids. Carotenoid-based pigments might be honest signals of fitness because they are derived from special diets and hence might be difficult to obtain, and/or because carotenoids are required for immune function and hence sexual displays come at

7998-438: The vaned feathers. The pennaceous feathers are vaned feathers. Also called contour feathers, pennaceous feathers arise from tracts and cover the entire body. A third rarer type of feather, the filoplume , is hairlike and are closely associated with pennaceous feathers and are often entirely hidden by them, with one or two filoplumes attached and sprouting from near the same point of the skin as each pennaceous feather, at least on

8091-422: The visible range. The wing feathers of male club-winged manakins Machaeropterus deliciosus have special structures that are used to produce sounds by stridulation . Some birds have a supply of powder down feathers that grow continuously, with small particles regularly breaking off from the ends of the barbules. These particles produce a powder that sifts through the feathers on the bird's body and acts as

8184-480: The webbing; however, that developmental process involves a tubular structure arising from a follicle and the tube splitting longitudinally to form the webbing. The number of feathers per unit area of skin is higher in smaller birds than in larger birds, and this trend points to their important role in thermal insulation, since smaller birds lose more heat due to the relatively larger surface area in proportion to their body weight. The miniaturization of birds also played

8277-675: The word pen itself is derived from the Latin penna , meaning feather. The French word plume can mean feather , quill , or pen . Feathers are among the most complex integumentary appendages found in vertebrates and are formed in tiny follicles in the epidermis , or outer skin layer, that produce keratin proteins . The β-keratins in feathers, beaks and claws – and the claws, scales and shells of reptiles – are composed of protein strands hydrogen-bonded into β-pleated sheets , which are then further twisted and crosslinked by disulfide bridges into structures even tougher than

8370-490: The yellow to red psittacofulvins (found in some parrots ) and the red turacin and green turacoverdin ( porphyrin pigments found only in turacos ). Structural coloration is involved in the production of blue colors, iridescence , most ultraviolet reflectance and in the enhancement of pigmentary colors. Structural iridescence has been reported in fossil feathers dating back 40 million years. White feathers lack pigment and scatter light diffusely; albinism in birds

8463-512: Was by assuming that primitive pterosaurs were scaly. A 2016 study analyzes the pulp morphology of the tail bristles of Psittacosaurus and finds they are similar to feathers but notes that they are also similar to the bristles on the head of the Congo peafowl , the beard of the turkey , and the spine on the head of the horned screamer . A reestimation of maximum likelihoods by paleontologist Thomas Holtz finds that filaments were more likely to be

8556-466: Was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae . Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system currently in use. Birds are categorised as the biological class Aves in Linnaean taxonomy . Phylogenetic taxonomy places Aves in the clade Theropoda as an infraclass or a subclass, more recently a subclass. Aves and

8649-674: Was shown to be an artefact of the fossilization process, as beta-protein structures are readily altered to alpha-helices during thermal degradation. In 2019, scientists found that genes for the production of feathers evolved at the base of archosauria, supporting that feathers were present at early ornithodirans and is consistent with the fossil record. Several non-avian dinosaurs had feathers on their limbs that would not have functioned for flight. One theory suggests that feathers originally evolved on dinosaurs due to their insulation properties; then, small dinosaur species which grew longer feathers may have found them helpful in gliding, leading to

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