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78-459: The gyrfalcon ( / ˈ dʒ ɜːr ˌ f ɔː ( l ) k ən / or / ˈ dʒ ɜːr ˌ f æ l k ən / ) ( Falco rusticolus ), also abbreviated as gyr , is a bird of prey from the genus Falco ( falcons and kestrels ) and the largest species of the family Falconidae . A high-latitude species, the gyrfalcon breeds on the Arctic coasts and tundra , the islands of northern North America and

156-672: A lammergeier might have killed Aeschylus by accident. Many stories of Brazilian indigenous peoples speak about children mauled by Uiruuetê, the Harpy Eagle in Tupi language . Various large raptors like golden eagles are reported attacking human beings, but its unclear if they intend to eat them or if they have ever been successful in killing one. Some fossil evidence indicates large birds of prey occasionally preyed on prehistoric hominids. The Taung Child , an early human found in Africa,

234-551: A commercial H5N2 influenza vaccine survived infection with a highly pathogenic H5N1 strain, whereas five unvaccinated falcons died. Thus, both wild and captive gyrfalcons can be protected from bird flu by vaccination. Bird of prey Birds of prey or predatory birds , also known as raptors , are hypercarnivorous bird species that actively hunt and feed on other vertebrates (mainly mammals , reptiles and other smaller birds). In addition to speed and strength, these predators have keen eyesight for detecting prey from

312-454: A distance or during flight, strong feet with sharp talons for grasping or killing prey, and powerful, curved beaks for tearing off flesh. Although predatory birds primarily hunt live prey, many species (such as fish eagles , vultures and condors ) also scavenge and eat carrion . Although the term "bird of prey" could theoretically be taken to include all birds that actively hunt and eat other animals, ornithologists typically use

390-467: A great deal of data is required. Dimorphisms can also be the product of intrasexual selection between males and females. It appears that both sexes of the species play a role in the sexual dimorphism within raptors; females tend to compete with other females to find good places to nest and attract males, and males competing with other males for adequate hunting ground so they appear as the most healthy mate. It has also been proposed that sexual dimorphism

468-573: A horizontal pursuit, rather than with the peregrine's speedy stoop from a height. Most prey is killed on the ground, whether they are captured there, or if the victim is a flying bird, forced to the ground. The diet is to some extent opportunistic, but a majority breed and hunt coinciding with ptarmigan and seabird colonies. Avian prey can range in size from redpolls around 20 g (0.71 oz) to geese and capercaillies up to 4 kg (8.8 lb) in weight, but ptarmigans ( Lagopus mutus ) and Willow Grouses ( L. lagopus ) are often chief prey in

546-465: A larger image to be projected onto the retina. The visual acuity of some large raptors such as eagles and Old World vultures are the highest known among vertebrates; the wedge-tailed eagle has twice the visual acuity of a typical human and six times that of the common ostrich , the vertebrate with the largest eyes. There are two regions in the retina, called the deep and shallow fovea, that are specialized for acute vision. These regions contain

624-452: A nonsynonymous point substitution was perfectly associated with the white/melanic polymorphism. In general, geographic variation follows Bergmann's rule for size and the demands of crypsis for plumage coloration. Several subspecies have been named according to perceived differences between populations but none of these are consistent and thus no living subspecies are currently accepted. The Icelandic population described as F. r. islandus

702-401: A relatively simple structure to both bones. The fifth distal tarsal disappears relatively early in evolution, with the remainder becoming the cuneiform and cuboid bones. Reptiles usually retain two centralia, while mammals typically have only one (the navicular). In birds, the tarsus has disappeared, with the proximal tarsals having fused with the tibia, the centralia having disappeared, and

780-459: A wingspan from 110 to 130 cm (43 to 51 in). Females are bulkier and larger, at 51 to 65 cm (20 to 25 + 1 ⁄ 2  in) long, 124 to 160 cm (49 to 63 in) wingspan, and of 1,180 to 2,100 g (2 lb 9 + 1 ⁄ 2  oz to 4 lb 10 oz) weight, with average weights of 1,585 or 1,752 g (3 lb 8 oz or 3 lb 13 + 3 ⁄ 4  oz). An outsized female from eastern Siberia

858-413: Is 58.46 mm × 45 mm ( 2 + 1 ⁄ 4  in ×  1 + 3 ⁄ 4  in); the average weight is 62 g ( 2 + 1 ⁄ 8  oz). The incubation period averages 35 days, with the chicks hatching at a weight of around 52 g ( 1 + 7 ⁄ 8  oz). The nestlings are brooded usually for 10 to 15 days and leave the nest at 7 to 8 weeks. At 3 to 4 months of age,

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936-600: Is a deprecated superorder within Raptores, formerly composed of the orders Falconiformes and Strigiformes. The clade was invalidated after 2012. Falconiformes is now placed in Eufalconimorphae , while Strigiformes is placed in Afroaves . The order Accipitriformes is believed to have originated 44 million years ago when it split from the common ancestor of the secretarybird ( Sagittarius serpentarius ) and

1014-729: Is a simplified phylogeny of Telluraves which is the clade where the birds of prey belong to along with passerines and several near-passerine lineages. The orders in bold text are birds of prey orders; this is to show the paraphyly of the group as well as their relationships to other birds. Accipitriformes (hawks, vultures, and relatives) [REDACTED] Strigiformes (owls) [REDACTED] Coraciimorphae (woodpeckers, rollers, hornbills, etc.) [REDACTED] Cariamiformes (seriemas) [REDACTED] Falconiformes (falcons) [REDACTED] Psittacopasserae (parrots and songbirds) [REDACTED] A recent phylogenomic study from Wu et al. (2024) has found an alternative phylogeny for

1092-492: Is an order of telluravian birds consisting of the living seriemas and extinct terror birds . Jarvis et al. 2014 suggested including them in the category of birds of prey, and McClure et al. 2019 considered seriemas to be birds of prey. The Peregrine Fund also considers seriemas to be birds of prey. Like most birds of prey, seriemas and terror birds prey on vertebrates . However, seriemas were not traditionally considered birds of prey. There were traditionally classified in

1170-549: Is believed to have been killed by an eagle-like bird similar to the crowned eagle . The Haast's eagle may have preyed on early humans in New Zealand , and this conclusion would be consistent with Maori folklore . Leptoptilos robustus might have preyed on both Homo floresiensis and anatomically modern humans, and the Malagasy crowned eagle , teratorns , Woodward's eagle and Caracara major are similar in size to

1248-445: Is commonly believed that the dimorphisms found in raptors occur due to sexual selection or environmental factors. In general, hypotheses in favor of ecological factors being the cause for sexual dimorphism in raptors are rejected. This is because the ecological model is less parsimonious , meaning that its explanation is more complex than that of the sexual selection model. Additionally, ecological models are much harder to test because

1326-516: Is derived from the Latin word rapio , meaning "to seize or take by force". The common names for various birds of prey are based on structure, but many of the traditional names do not reflect the evolutionary relationships between the groups. Many of these English language group names originally referred to particular species encountered in Britain . As English-speaking people travelled further,

1404-411: Is merely the product of disruptive selection , and is merely a stepping stone in the process of speciation, especially if the traits that define gender are independent across a species. Sexual dimorphism can be viewed as something that can accelerate the rate of speciation. In non-predatory birds, males are typically larger than females. However, in birds of prey, the opposite is the case. For instance,

1482-494: Is perhaps the most distinct. The predominantly white Arctic forms are parapatric and seamlessly grade into the subarctic populations. The Icelandic types are presumed to have less gene flow with their neighbors; they show less variation in plumage colors. Comprehensive phylogeographic studies to determine the proper status of the Icelandic population have yet to be performed. A population genetic study, however, identified

1560-471: Is required to determine the ecological factors contributing to these distributions relative to plumage differences, a study using demographic data suggested that plumage color distribution in Greenland may be influenced by nesting chronology with white individuals and pairs laying eggs earlier in the breeding season and producing more offspring. A paleosubspecies , Falco rusticolus swarthi , existed during

1638-717: Is the Late Latin term for a falcon, Falco , from falx a sickle , referencing the talons of the bird. The species name is from the Latin rusticolus , a countryside-dweller, from rus , "country" and colere , "to dwell". The bird's common name comes from French gerfaucon ; in Medieval Latin , it is gyrofalco . The first part of the word may come from Old High German gîr ( cf. modern German Geier ; ultimately from Proto-Germanic * girį̄ ("greed")) for " vulture ", referring to its size in comparison with other falcons ; or from

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1716-485: The Eurosiberian region, where it is mainly a resident species. Some gyrfalcons disperse more widely after the breeding season or in winter, and individual vagrancy can take birds for long distances. Its plumage varies with location, with birds being coloured from all-white to dark brown. These colour variations are called morphs . Like other falcons, it shows sexual dimorphism , with the female much larger than

1794-612: The Late Pleistocene (125,000 to 13,000 years ago). Fossils found in Little Box Elder Cave ( Converse County, Wyoming ), Dark Canyon Cave ( Eddy County, New Mexico ), and McKittrick, California were initially described as Falco swarthi ("Swarth falcon" or more properly "Swarth's gyrfalcon") on account of their distinct size. They have meanwhile proven to be largely inseparable from those of living gyrfalcons, except for being somewhat larger. Swarth's gyrfalcon

1872-845: The Latin gȳrus for "circle" or "curved path", in turn from the Ancient Greek γῦρος , gûros , meaning "circle" – from the species' circling as it searches for prey, distinct from the hunting of other falcons in its range. The male gyrfalcon is called a gyrkin in falconry. The gyrfalcon is the largest falcon in the world, being about the same size as the largest buteos but probably slightly heavier. Males are 48 to 61 centimetres (19 to 24 inches) long, weigh 805 to 1,350 grams (1 pound 12 + 1 ⁄ 2  ounces to 2 pounds 15 + 1 ⁄ 2  ounces), with average weights reported as 1,130 or 1,170 g (2 lb 8 oz or 2 lb 9 + 1 ⁄ 2  oz) and have

1950-497: The kestrel is a type of falcon in which males are the primary providers, and the females are responsible for nurturing the young. In this species, the smaller the kestrels are, the less food is needed and thus, they can survive in environments that are harsher. This is particularly true in the male kestrels. It has become more energetically favorable for male kestrels to remain smaller than their female counterparts because smaller males have an agility advantage when it comes to defending

2028-641: The merlin ( Falco columbarius ). The taxonomy of Carl Linnaeus grouped birds (class Aves) into orders, genera, and species, with no formal ranks between genus and order. He placed all birds of prey into a single order, Accipitres , subdividing this into four genera: Vultur (vultures), Falco (eagles, hawks, falcons, etc.), Strix (owls), and Lanius (shrikes). This approach was followed by subsequent authors such as Gmelin , Latham and Turton . Louis Pierre Vieillot used additional ranks: order, tribe, family, genus, species. Birds of prey (order Accipitres) were divided into diurnal and nocturnal tribes;

2106-399: The peregrine falcon , which it is known to compete with (and occasionally hunt). It differs from the buzzard in general structure, having pointed wings. The gyrfalcon is a very polymorphic species, so its plumage varies greatly. The archetypal morphs are called "white", "silver", "brown", and "black", though they can be coloured on a spectrum from all-white to very dark. The brown form of

2184-485: The subtalar joint , to the calcaneus or heel bone. Together, the talus and calcaneus form the hindfoot. The five irregular bones of the midfoot—the cuboid , navicular , and three cuneiform bones—form the arches of the foot which serves as a shock absorber. The midfoot is connected to the hind- and forefoot by muscles and the plantar fascia . The complex motion of the subtalar joint occurs in three planes and produces subtalar inversion and eversion . Along with

2262-475: The Haast's eagle, implying that they similarly could pose a threat to a human being. Birds of prey have incredible vision and rely heavily on it for a number of tasks. They utilize their high visual acuity to obtain food, navigate their surroundings, distinguish and flee from predators, mating, nest construction, and much more. They accomplish these tasks with a large eye in relation to their skull, which allows for

2340-577: The Iceland population as genetically unique relative to other sampled populations in both eastern and western Greenland, Canada, Alaska, and Norway. Further, within Greenland, differing levels of gene flow between western and eastern sampling locations were identified, with apparent asymmetric dispersal in western Greenland from north to south. This dispersal bias is in agreement with the distribution of plumage colour variants with white gyrfalcons in much higher proportion in north Greenland. Although further work

2418-602: The Jurchen; under the last Liao emperor , tax collectors were entitled to use force to procure sufficient gyrfalcons. This was one cause of the Jurchen rebellion, whose leader Aguda annihilated the Liao empire in 1125, and established the Jin dynasty in its stead. Falcons are known to be very susceptible to avian influenza . Therefore, an experiment was done with hybrid gyr- saker falcons, which found that five falcons vaccinated with

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2496-489: The accipitrid species. The phylogeny of Accipitriformes is complex and difficult to unravel. Widespread paraphylies were observed in many phylogenetic studies. More recent and detailed studies show similar results. However, according to the findings of a 2014 study, the sister relationship between larger clades of Accipitriformes was well supported (e.g. relationship of Harpagus kites to buzzards and sea eagles and these latter two with Accipiter hawks are sister taxa of

2574-428: The allele distributions for the color polymorphism form clines and in darker birds of unknown origin, theoretically any allele combination might be present. For instance, a mating of a pair of captive gyrfalcons is documented to have produced a clutch of four young: one white, one silver, one brown, and one black. Molecular work suggests plumage color is associated with the melanocortin 1 receptor gene ( MC1R ), where

2652-456: The back and wings being most common. Other subpopulations have varying amounts of the darker morphs: the Icelandic birds tend towards pale, whereas the Eurasian populations are considerably darker and typically incorporate no white birds. Natural separation into regional subspecies is prevented by gyrfalcons' habit of flying long distances whilst exchanging alleles between subpopulations; thus,

2730-697: The bills of birds of prey shown by hunters. In Britain, kites and buzzards were seen as destroyers of game and killed, for instance in 1684–5 alone as many as 100 kites were killed. Rewards for their killing were also in force in the Netherlands from 1756. From 1705 to 1800, it has been estimated that 624087 birds of prey were killed in a part of Germany that included Hannover, Luneburg, Lauenburg and Bremen with 14125 claws deposited just in 1796–97. Many species also develop lead poisoning after accidental consumption of lead shot when feeding on animals that had been shot by hunters. Lead pellets from direct shooting that

2808-531: The biogeographic realms of the Southern Hemisphere. The appearance of migratory behaviour occurred in the tropics parallel with the range expansion of migratory species to temperate habitats. Similar results of southern origin in other taxonomic groups can be found in the literature. Distribution and biogeographic history highly determine the origin of migration in birds of prey. Based on some comparative analyses, diet breadth also has an effect on

2886-586: The birds have escaped from also cause reduced fitness and premature deaths. Some evidence supports the contention that the African crowned eagle occasionally views human children as prey, with a witness account of one attack (in which the victim, a seven-year-old boy, survived and the eagle was killed), and the discovery of part of a human child skull in a nest. This would make it the only living bird known to prey on humans, although other birds such as ostriches and cassowaries have killed humans in self-defense and

2964-559: The birds to make a comeback. The gyrfalcon has long associated with humans, primarily for hunting and in the art of falconry . It is the official bird of Canada's Northwest Territories . The white falcon in the crest of the Icelandic Republic 's coat of arms is a variety of gyrfalcon. The white phase gyrfalcon is the official mascot of the United States Air Force Academy . In the medieval era,

3042-437: The bones of the lower limb. These are followed by a second row of four bones, referred to as the centralia (singular: centrale ), and then a row of five distal tarsals, each articulating with a single metatarsal. In the great majority of tetrapods, including all of those alive today, this simple pattern is modified by the loss and fusion of some of the bones. In reptiles and mammals, there are normally just two proximal tarsals,

3120-462: The calcaneus (equivalent to the amphibian fibulare) and the talus (probably derived from a fusion of multiple bones). In mammals, including humans, the talus forms a hinge joint with the tibia, a feature especially well developed in the artiodactyls . The calcaneus is also modified, forming a heel for the attachment of the Achilles tendon . Neither of these adaptations is found in reptiles, which have

3198-523: The clade containing Aquilinae and Harpiinae). The diurnal birds of prey are formally classified into six families of two different orders (Accipitriformes and Falconiformes). These families were traditionally grouped together in a single order Falconiformes but are now split into two orders, the Falconiformes and Accipitriformes . The Cathartidae are sometimes placed in a separate order Cathartiformes . Formerly, they were sometimes placed in

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3276-475: The dark side of slate grey . A color variety that arose in captive breeding is "black chick". The gyrfalcon is a member of the hierofalcon complex. In this group, ample evidence indicates hybridisation and incomplete lineage sorting , which confounds analyses of DNA sequence data to a massive extent. The radiation of the entire living diversity of hierofalcons took place around the Eemian Stage at

3354-486: The early 2000s, it was observed that as possible climate change began to temper the Arctic summers, peregrine falcons were expanding their range north to parts of Greenland , and competing with gyrfalcons. Although it is specially adapted for high-Arctic life, and larger than the peregrine, the gyrfalcon is less aggressive and more conflict-averse, and so is less able to compete with peregrines, which can attack and overwhelm

3432-439: The evolution of migratory behaviour in this group, but its relevance needs further investigation. The evolution of migration in animals seems to be a complex and difficult topic with many unanswered questions. A recent study discovered new connections between migration and the ecology, life history of raptors. A brief overview from abstract of the published paper shows that "clutch size and hunting strategies have been proved to be

3510-471: The existing literature combining anatomical, genetic, and behavioural studies showed that, in general, raptors have functional olfactory systems that they are likely to use in a range of different contexts. Birds of prey have been historically persecuted both directly and indirectly. In the Danish Faroe Islands , there were rewards Naebbetold (by royal decree from 1741) given in return for

3588-493: The familiar names were applied to new birds with similar characteristics. Names that have generalised this way include: kite ( Milvus milvus ), sparrowhawk or sparhawk ( Accipiter nisus ), goshawk ( Accipiter gentilis ), kestrel ( Falco tinninculus ), hobby ( Falco subbuteo ), harrier (simplified from "hen-harrier", Circus cyaneus ), buzzard ( Buteo buteo ). Some names have not generalised, and refer to single species (or groups of closely related (sub)species), such as

3666-579: The genetic lineage of the Altai falcon . However, recent genetic research has not found distinct genetic clusters differentiating Altai falcons from eastern saker falcons ( Falco cherrug milvipes ), nor evidence supporting the hybridization theory. Instead, this research suggests that gyrfalcons may have evolved from eastern saker falcons, explaining their close genetic relationship. Some correlation exists between locality and colour morph. Greenland gyrfalcons are lightest, with white plumage flecked with grey on

3744-667: The gyrfalcon is distinguished from the peregrine by the cream streaking on the nape and crown and by the absence of a well-defined malar stripe and cap. The black morph is similar but has a strongly black-spotted underside, rather than finely barred as in the peregrine and the brown-morph gyrfalcon. White form gyrfalcons are the only predominantly white falcons. Silver gyrfalcons resemble a light grey lanner falcon of larger size. The species shows no sex-based colour differences; juveniles are darker and browner than adults. The black color seems to be sex-linked and to occur mostly in females; it proved difficult for breeders to get males darker than

3822-528: The gyrfalcon was considered a royal bird. The geographer and historian Ibn Sa'id al-Maghribi (d. 1286) described certain northern Atlantic islands west of Ireland where these falcons would be brought from, and how the Egyptian Sultan paid 1,000 dinars for each gyrfalcon (or, if it arrived dead, 500 dinars). Due to its rarity and the difficulties involved in obtaining it, in European falconry

3900-626: The gyrfalcon was reserved for kings and nobles; very rarely was a man of lesser rank seen with a gyrfalcon on his fist. In the 12th century AD China, swan-hunting with gyrfalcons (海東青 hǎidōngqīng in Chinese) obtained from the Jurchen tribes became fashionable among the Khitan nobility. When demand for gyrfalcons exceeded supply, the Liao Emperor imposed a tax payment-in-kind of gyrfalcons on

3978-466: The gyrs. However, it remains on the IUCN's Red List with a Conservation Status of Least Concern . The gyrfalcon almost invariably nests on cliff faces. Breeding pairs do not build their own nests, and often use a bare cliff ledge or the abandoned nest of other birds, particularly golden eagles and common ravens . The clutch can range from 1 to 5 eggs, but is usually 2 to 4. The average size of an egg

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4056-400: The highest density of photoreceptors, and provide the highest points of visual acuity. The deep fovea points forward at an approximate 45° angle, while the shallow fovea points approximately 15° to the right or left of the head axis. Several raptor species repeatedly cock their heads into three distinct positions while observing an object. First, is straight ahead with their head pointed towards

4134-425: The highly acute deep fovea. Like all birds, raptors possess tetrachromacy , however, due to their emphasis on visual acuity, many diurnal birds of prey have little ability to see ultraviolet light as this produces chromatic aberration which decreases the clarity of vision. Tarsus (skeleton) The tarsus articulates with the bones of the metatarsus, which in turn articulate with the proximal phalanges of

4212-415: The horizontal plane and 57 degrees anteromedially (forward-inward). In vitro talonavicular motion is 7 degrees flexion-extension and 17 degrees pronation-supination; while calcaneocuboid motion is 2 degrees flexion-extension and 7 degrees pronation-supination. The motions of the subtalar and transverse talar joints interact to make the foot either flexible or rigid. With the subtalar joint in eversion,

4290-660: The immature gyrfalcons become independent of their parents, though they may associate with their siblings through the following winter. The only natural predators of gyrfalcons are golden eagles , and even they rarely engage with these formidable falcons. Gyrfalcons have been recorded as aggressively harassing animals that come near their nests, although common ravens are the only predators known to successfully pick off gyrfalcon eggs and hatchlings. Even brown bears have been reportedly dive-bombed. Humans, whether accidentally (automobile collisions or poisoning of carrion to kill mammalian scavengers) or intentionally (through hunting), are

4368-480: The leading cause of death for gyrfalcons. Gyrfalcons that survive into adulthood can live up to 20 years of age. As F. rusticolus has such a wide range, it is not considered a threatened species by the IUCN . It is not much affected by habitat destruction , but pollution, for instance by pesticides , depressed its numbers in the mid-20th century, and until 1994 it was considered " Near Threatened ". Improving environmental standards in developed countries have allowed

4446-460: The limit of load that they can carry, gyrfalcons mainly take young hares, but both male and female falcons can take down adult hares up 4.5 kg (9.9 lb) in weight and bring dismembered pieces to their nest. Other mammalian prey can include water voles , muskrats , stoats , minks , Arctic fox pups, and rarely also bats . Prey other than birds and mammals are extremely rare, but brown trout ( Salmo trutta ) have been recorded as prey. In

4524-416: The male. For centuries, the gyrfalcon has been valued as a hunting bird . Typical prey includes the ptarmigan and waterfowl , which it may attack in flight; and it also hunts fish and small mammals . The gyrfalcon was formally described by Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under its current binomial name Falco rusticolus . The genus name

4602-603: The most important variables in shaping distribution areas, and also the geographic dissimilarities may mask important relationships between life history traits and migratory behaviours. The West Palearctic-Afrotropical and the North-South American migratory systems are fundamentally different from the East Palearctic-Indomalayan system, owing to the presence versus absence of ecological barriers." Maximum entropy modelling can help in answering

4680-821: The narrower definition followed in this page, excluding many piscivorous predators such as storks , cranes , herons , gulls , skuas , penguins , and kingfishers , as well as many primarily insectivorous birds such as passerines (e.g. shrikes ), nightjars , frogmouths , songbirds such as crows and ravens , alongside opportunistic predators from predominantly frugivorous or herbivorous ratites such as cassowaries and rheas . Some extinct predatory telluravian birds had talons similar to those of modern birds of prey, including mousebird relatives ( Sandcoleidae ), and Messelasturidae indicating possible common descent . Some Enantiornithes also had such talons, indicating possible convergent evolution , as enanthiornithines weren't even modern birds . The term raptor

4758-444: The nest and hunting. Larger females are favored because they can incubate larger numbers of offspring, while also being able to brood a larger clutch size. It is a long-standing belief that birds lack any sense of smell, but it has become clear that many birds do have functional olfactory systems . Despite this, most raptors are still considered to primarily rely on vision, with raptor vision being extensively studied. A 2020 review of

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4836-629: The object. Second and third are sideways to the right or left of the object, with their head axis positioned approximately 40° adjacent to the object. This movement is believed to be associated with lining up the incoming image to fall on the deep fovea. Raptors will choose which head position to use depending on the distance to the object. At distances as close as 8m, they used primarily binocular vision. At distances greater than 21m, they spent more time using monocular vision. At distances greater than 40m, they spent 80% or more time using their monocular vision. This suggests that raptors tilt their head to rely on

4914-470: The oldest dates published so far in the case of birds of prey. For example, a previous reconstruction of migratory behaviour in one Buteo clade with a result of the origin of migration around 5 million years ago was also supported by that study. Migratory species of raptors may have had a southern origin because it seems that all of the major lineages within Accipitridae had an origin in one of

4992-412: The order Ciconiiformes . The secretary bird and/or osprey are sometimes listed as subfamilies of Acciptridae: Sagittariinae and Pandioninae, respectively. Australia's letter-winged kite is a member of the family Accipitridae , although it is a nocturnal bird. The nocturnal birds of prey—the owls —are classified separately as members of two extant families of the order Strigiformes : Below

5070-503: The order Gruiformes . And they are still not considered birds of prey in general parlance. Their bodies are also shaped completely differently from birds of prey. They have long legs and long necks. While secretarybirds also have long legs, they otherwise resemble raptors. Seriemas do not. Their beak is hooked, but too long. Migratory behaviour evolved multiple times within accipitrid raptors. The earliest event occurred nearly 14 to 12 million years ago. This result seems to be one of

5148-813: The owls remained monogeneric (family Ægolii, genus Strix ), whilst the diurnal raptors were divided into three families: Vulturini, Gypaëti, and Accipitrini. Thus Vieillot's families were similar to the Linnaean genera, with the difference that shrikes were no longer included amongst the birds of prey. In addition to the original Vultur and Falco (now reduced in scope), Vieillot adopted four genera from Savigny: Phene , Haliæetus , Pandion , and Elanus . He also introduced five new genera of vultures ( Gypagus , Catharista , Daptrius , Ibycter , Polyborus ) and eleven new genera of accipitrines ( Aquila , Circaëtus , Circus , Buteo , Milvus , Ictinia , Physeta , Harpia , Spizaëtus , Asturina , Sparvius ). Falconimorphae

5226-833: The placement of the birds of prey. Their analysis has found support in a clade consisting of the Strigiformes and Accipitriformes in new clade Hieraves . Hieraves was also recovered to be the sister clade to Australaves (which it includes the Cariamiformes and Falconiformes along with Psittacopasserae ). Below is their phylogeny from the study. Coraciimorphae (woodpeckers, rollers, hornbills, etc.) [REDACTED] Strigiformes (owls) [REDACTED] Accipitriformes (hawks, vultures, and relatives) [REDACTED] Cariamiformes (seriemas) [REDACTED] Falconiformes (falcons) [REDACTED] Psittacopasserae (parrots and songbirds) [REDACTED] Cariamiformes

5304-464: The question: why species winters at one location while the others are elsewhere. Temperature and precipitation related factors differ in the limitation of species distributions. "This suggests that the migratory behaviours differ among the three main migratory routes for these species" which may have important conservational consequences in the protection of migratory raptors. Birds of prey (raptors) are known to display patterns of sexual dimorphism . It

5382-450: The right foot, about which subtalar motion occurs. So, during subtalar inversion, the calcaneus also rotates clockwise and translates forward along the axis of the screw. Average subtalar motion is 20-30 degrees inversion and 5-10 degrees eversion. Functional motion during the gait cycle is 10-15 degrees (the heel strikes the ground in slight inversion followed by quick eversion). The talonavicular and calcaneocuboid joints (i.e. between

5460-546: The sea and landbirds which make up much of the American gyrfalcon's diet today. The gyrfalcon was originally thought to be a bird of tundra and mountains only; however, in June 2011, it was revealed to spend considerable periods during the winter on sea ice far from land. It feeds only on birds and mammals , the latter of which it takes more regularly than many other Falco species. Like other hierofalcons, it usually hunts in

5538-527: The start of the Late Pleistocene . It represents lineages that expanded into the Holarctic and adapted to local conditions; this is in contrast to less northerly populations of northeastern Africa (where the radiation probably originated) that evolved into the saker falcon . Previous beliefs held that gyrfalcons hybridized with sakers in the Altai Mountains , and this gene flow contributed to

5616-430: The talus and navicular bones, and the calcaneus and cuboid bones) form the so-called transverse tarsal joint or Chopart's joint. It has two axes of motion. Inversion and eversion occur about a longitudinal axis oriented 15 degrees upward from the horizontal plane and 9 degrees medially from the longitudinal axis of the foot. Flexion and extension occur primarily about an oblique axis oriented 52 degrees upward from

5694-418: The toes. The joint between the tibia and fibula above and the tarsus below is referred to as the ankle joint proper . In humans the largest bone in the tarsus is the calcaneus, which is the weight-bearing bone within the heel of the foot. The talus bone or ankle bone is connected superiorly to the two bones of the lower leg, the tibia and fibula, to form the ankle joint or talocrural joint; inferiorly, at

5772-405: The transverse tarsal joint (i.e. talonavicular and calcaneocuboid joint), the subtalar joint transforms tibial rotation into forefoot supination and pronation . The axis of rotation in the joint is directed upward 42 degrees from the horizontal plane and 16 degrees medially from the midline of the foot. However, together, the subtalar facets form a screw or Archimedean spiral , right-handed in

5850-478: The tundra. Seabirds such as auks , gulls and seaducks may predominate in coastal areas, and waders and ducks such as mallards ( Anas platyrhynchos ) on wetlands. Other avian prey include corvids , smaller passerines , doves , and other birds of preys . Mammalian prey can be locally important, mainly Arctic ground squirrels (Spermophilus parryii) and Arctic hares (Lepus arcticus), and occasionally Norway lemming ( Lemmus lemmus ) in peak years. Due to

5928-467: The two joints of the transverse joint are parallel, which make movements in this joint possible. With the subtalar joint in inversion, the axes of the transverse joint are convergent, movements in this joint are thus locked and the midfoot rigid. In primitive tetrapods , such as Trematops , the tarsus consists of three rows of bones. There are three proximal tarsals, the tibiale , intermedium , and fibulare , named for their points of articulation with

6006-434: Was found to have scaled 2,600 g (5 lb 12 oz). Among standard measurements, the wing chord is 34.5 to 41 cm (13.6 to 16.1 in), the tail is 19.5 to 29 cm (7.7 to 11.4 in), the culmen is 2 to 2.8 cm ( 3 ⁄ 4 to 1 + 1 ⁄ 8  in) and the tarsus is 4.9 to 7.5 cm ( 1 + 7 ⁄ 8 to 3 in). The gyrfalcon is larger, broader-winged and longer-tailed than

6084-461: Was on the upper end of the present gyrfalcon's size range, with some stronger females even surpassing it. It seems to have had some adaptations to the temperate semiarid climate that predominated in its range during the last ice age . Ecologically more similar to current Siberian populations (which are generally composed of smaller birds) or to the prairie falcon , this temperate steppe population must have preyed on landbirds and mammals rather than

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