To observe gyrfalcons in the wild, the best time is usually the winter when they seasonally disperse from their breeding grounds. Open areas, similar to the arctic tundra, with food will usually have a visiting gyrfalcon in northern climates. Open water with overwintering waterfowl is especially good areas to see these birds. Large numbers of rock doves may also prove to be areas where gyrfalcons will hunt.
Normally, patience is required to view these birds, as they are rare, even in their normal range. To view one in the wild is special, to see one hunt in the wild is extraordinary.
Perception Channels: visual ; tactile ; acoustic ; chemical
In Canada, the gyrfalcon is not recorded as endangered, threatened, or species of special concern. Population estimates are currently thought to be under 50 000 birds total, with many of these being sub-adults and not sexually mature. Also, population levels have stayed fairly constant with little flucuation over the long term. This is perhaps due to the fact that habitat loss is not a major concern due to low human interaction in the north, the fact that there is no hunting season on these birds, and pesticides levels have been lower in these non-migrators.
In the United States this species has been given no special status as it is only a vagrant visitor and does not breed in the mainland USA. This species does however, nest in Alaska where populations seem to be stable.
Poaching, mainly in the form of capturing and selling birds to falconers is still a major concern. Due to tight restrictions on exporting in Canada, this does not occur very often or at least is not detected very often. Also, due to its habitat and its remoteness, these birds are not regularly captured.
Raptor monitoring, through surveys and banding is becoming more prevalent, however, do to their remoteness, not all areas are covered in as great of detail. This is due to the fact that birds of prey are good indicators to overall ecosystem health. By monitoring these large birds, we can determine if the ecosystem is on a downward slide early and try to restore it.(Poole and Bromley 1985;)
US Migratory Bird Act: protected
US Federal List: no special status
CITES: appendix i
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no reported negative impacts by the gyrfalcon on humans.
Falconry is one of the oldest sports dating back some 4000 years, the majority practiced in the middle east. The white phase of the gyrfalcon, historically was hunted only by royality, and even today is still considered the "bird of kings". In North America, collecting wild raptors is illegal, but they are captured for trade in portions of their range in the Old World. McLean (1984) reports the demand to be high from the middle east, while Trefry (2000, personal communication) suggests few gyrfalcons are bred in captivity. Unfortunately, many are captured illegally and sold on the black market.
Another economic aspect of this bird is its rarity to birdwatchers, many of whom are willing to travel to watch, study and photograph this bird. These travellers must be transported, fed, and sheltered, all of which have economics spinoffs to the communities where these birds are found.
To a small extent, these birds are hunted for food and feathers used for clothing or ceremonial purposes by native Inuit. This number is small and they are not hunted exclusively, only opprotunistically and are spiritually significant to the native people of the north (Holt 1999, personal communication; McLean 1984; Trefry 2000, personal communication)
Unlike eagles which use their large size to rob meals, and peregrine falcons which use gravity to gain tremendous speed, the gyrfalcon uses raw power to capture prey, usually in a tail chase. Usually low coursing flights are used in open habitat (no trees for concealment) where gyrfalcons will strike prey both in the air or on the ground . The majority of prey (by biomass) that consitutes the diet consists of ptarmigan (Lagopus sp.), Arctic ground squirrel (Spermophilus parryii) and Arctic hares (Lepus arcticus). Other prey includes other small mammals (mice and voles) as well as other birds (ducks, sparrows, buntings)
While hunting, this falcon uses keen eyesight to spot potential prey, as almost all animals in the north are cryptically colored to avoid detection. When potential prey is spotted a chase usually occurs where more than likely the prey will be knocked to the ground in a powerful blow from the talons and then pounced upon. Gyrfalcons are powerful enough to have sustained flight while hunting and occasionally wear their prey out until capture is easy. During nesting, the gyrfalcon will also cache meals with large prey such as Arctic hares between feedings. Rock doves (Columba livia), or pigeons as they are commonly known, although not native are preyed upon heavily in major centers by gyrfalcons during winter months (Lange and Dekker 1999; Stelfox and Fisher 1998; Cade 1982; Poole 1987).
The gyrfalcon (Falco rusticolus) is an arctic dwelling species with a holarctic distribution. It is rarely found south of 60 degrees. The majority of the breeding range is found north of 60 degrees while in parts of Eastern Canada it can be found breeding to 55 degrees, mainly along sea coasts. Although gyrfalcons are non-migratory, they will disperse from the breeding range during the winter season, very rarely reaching the northern limit of the United States (Poole 1987; Wheeler and Clark 1995; Cade 1982).
Biogeographic Regions: nearctic (Native ); palearctic (Native )
The gyrfalcon is typically found in northern latitudes away from the boreal forest. Although some individuals have been recorded nesting in trees, the majority of individuals of this species nest in the arctic tundra. Nesting habitat is usually among tall cliffs while the hunting and foraging areas are more diverse. Foraging areas may include coastal areas and beaches that are used heavily by waterfowl, stooping off cliffs at unsuspecting prey such as small birds beneath them, or on the open tundra where tail chases on ptarmigan and larger mammals is common.
Habitat fragmentation is currently not a threat to this species, due mainly to the short growing season and climate of the area. Since cliff faces are not disturbed and the tundra is not highly altered nor farmed, habitat for this species seems to be stable.
Winter can force this species to move regionally to feed. While in more southern climates, they prefer agricultural fields which remind them of their northern breeding grounds, typically perching low to the ground on fence posts (Pletz, E. 2000 personal communication; Poole 1987).
Terrestrial Biomes: tundra
Average lifespan
Status: wild: 162 months.
The world's largest falcon is polymorphic, being recognized in three color phases: white, grey, and dark. The dark phase is dark grey, almost black, in some individuals and groups of this morph are found in northern Canada. The white morph is generally found in Greenland, and is usually almost pure white with some markings usually on the wings. The grey morph is an intermediate and found throughout the range, typically two tones of grey are found on the body, most easily beind seen on the flight feathers versus the rest of the wing. This species is sexually dimorphic and thus has a wide ranging weight. Males weigh 800-1300g, averaging 53cm total length and females weigh 1400-2100g, averaging 56cm total length. The shape of the gyrfalcon is characteristically the same as most falcons. This includes long pointed wings (unlike the rounded wings of buteos), long tail and a notched bill. It also however, differs from other falcons by large size, shorter wings that only extend 2/3 down the tail when perched (compared with other falcons where the wings extend all the way to the tail), and broader wings. Adults characteristically have yellow ceres, eye-rings and legs while juveniles display these features in a blue color. As in all falcons, the eyes appear black. This species may perhaps only be confused with the Northern Goshawk (Accipiter gentilis) which inhabits dense forests, or the Peregrine Falcon (Falco peregrinus) which is somewhat smaller with a dark slaty-blue-black "helmet" and a lighter underside(Wheeler and Clark 1995; Cade 1982).
Range mass: 800 to 2100 g.
Other Physical Features: endothermic ; bilateral symmetry
Gyrfalcons nest in the remote northern portions of the world. Until recently, little was known about nesting sites, incubation times, fledging dates, or reproductive behavior. Although much has been discovered recently, many other aspects of the reproductive cycle have yet to be determined.
Males begin defending nesting territory in mid-winter, about the end of January, while females generally arrive at nesting sites near the beginning of March. Pair bonding occurs for about 6 weeks and subsequently the eggs are usually laid near the end of April.
Gyrfalcons do not construct their own stick nests in trees (although old common raven (Corvus corax) stick nests in trees are sometimes used), and usually find suitable nesting sites on cliff faces where there is a shelf with an overhang. Nest sites are used year after year and accumulate prey remain piles, while the rocks turn white from excessive guano.
The clutch can be from 2-7 eggs, however,the average size is 4, which is typically incubated by the female with some assistance from the male. Incubation has recently been determined to be 35 days and all birds in the clutch hatch within a 24-36 hour period.
Due to cold climate, chicks are covered in heavy down and are left to thermoregulate themselves after only 10 days as the female leaves the nest to join the male in hunting duties for the growing family (Cade 1982).
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
The gyrfalcon (/ˈdʒɜːrˌfɔː(l)kən/ or /ˈdʒɜːrˌfælkən/)[3] (Falco rusticolus), the largest of the falcon species, is a bird of prey. The abbreviation gyr is also used.[4] It breeds on Arctic coasts and tundra, and the islands of northern North America and the Eurosiberian region. It is mainly a resident there also, but some gyrfalcons disperse more widely after the breeding season, or in winter. 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 the male. For centuries, the gyrfalcon has been valued as a hunting bird. Typical prey includes the ptarmigan and waterfowl, which it may take in flight; it also takes fish and 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.[5] The genus name is the Late Latin term for a falcon, Falco, from falx a sickle, referencing the talons of the bird.[6] The species name is from the Latin rusticolus, a countryside-dweller, from rus, "country" and colere, "to dwell".[7] 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 compared to other falcons; or from 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.[nb 1] 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 (buzzards) 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 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).[8][9] An outsized female from eastern Siberia was found to have scaled 2,600 g (5 lb 12 oz).[9][10] 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).[11] The gyrfalcon is larger, broader-winged and longer-tailed than 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 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 has a strongly black-spotted underside, rather than finely barred as in the peregrine. 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 the dark side of slate grey. A color variety that arose in captive breeding is "black chick".[12]
Painting of a Greenland white morph (center), an intermediate (lower left), and black morph (back)
Light silver-morph
Male with a darker "silver" coloration
Painting of brown morph adult (center) and juveniles
Icelandic gyrfalcon, 1759
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 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. Gyrfalcons hybridize not infrequently with sakers in the Altai Mountains, and this gene flow seems to be the origin of the Altai falcon.[13][14][15][16]
Some correlation exists between locality and colour morph. Greenland gyrfalcons are lightest, with white plumage flecked with grey on 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, the allele distributions for the color polymorphism form clines and in darker birds[nb 2] 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 a nonsynonymous point substitution was perfectly associated with the white/melanic polymorphism.[17]
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[nb 3][18][19] but none of these are consistent and thus no living subspecies are currently accepted. The Icelandic population described as F. r. islandus 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.[18][20]
A population genetic study,[19] however, identified 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.[19] Although further work 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.[21]
A paleosubspecies, Falco rusticolus swarthi, existed during 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.[22][23][24][25]
Swarth's gyrfalcon was on the upper end of the present gyrfalcon's size range, with some stronger females even surpassing it.[23] 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 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.[26] 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 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 the tundra.[27][28][29][30][31][32] Seabirds such as auks, gulls and seaducks may predominate in coastal areas, and waders and ducks such as mallards (Anas platyrhynchos) on wetlands.[29][33] Other avian prey include corvids, smaller passerines, doves, and other birds of preys.[34][35]
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.[29] Due to 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.[27][36][37][38] Other mammalian prey can include water voles, muskrats, stoats, Arctic fox pups, and rarely also bats.[30][36][37][39] Prey other than birds and mammals are extremely rare, but brown trout (Salmo trutta) have been recorded as prey.[32]
In 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 the gyrs.[40] 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 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, 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 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.[1] 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 the birds to make a comeback.[1]
Falco rusticolus egg
Nestling in Alaska
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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.[41]
In the medieval era, 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).[42] Due to its rarity and the difficulties involved in obtaining it, in European falconry the gyrfalcon was reserved for kings and nobles; very rarely was a man of lesser rank seen with a gyrfalcon on his fist.[43]
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 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.[44]
Most historians agree that the coat of arms of Ukraine, the medieval symbol, was not intended to depict a trident, but most likely a stylized falcon. Depictions of a flying falcon with a cross above its head have been found in Old Ladoga, the first seat of Kievan Rurik dynasty,[45] of Scandinavian lineage.[46] For centuries falconry has been a royal sport in Europe. Also known also as the Norwegian falcon, it was considered a royal bird and is mentioned (uk: кречет) in one of the earliest epics of Ruthenia, the 12th century poem The Tale of Igor's Campaign. The gyrfalcon is related to other falcons. 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 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.[47]
The gyrfalcon (/ˈdʒɜːrˌfɔː(l)kən/ or /ˈdʒɜːrˌfælkən/) (Falco rusticolus), the largest of the falcon species, is a bird of prey. The abbreviation gyr is also used. It breeds on Arctic coasts and tundra, and the islands of northern North America and the Eurosiberian region. It is mainly a resident there also, but some gyrfalcons disperse more widely after the breeding season, or in winter. 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 the male. For centuries, the gyrfalcon has been valued as a hunting bird. Typical prey includes the ptarmigan and waterfowl, which it may take in flight; it also takes fish and mammals.
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