|Adult in Northern Territory, Australia|
17–19, see text
|Global range of F. peregrinus
Breeding summer visitor
and see text
The peregrine falcon (Falco peregrinus), also known as the peregrine, and historically as the duck hawk in North America, is a widespread bird of prey (raptor) in the family Falconidae. A large, crow-sized falcon, it has a blue-grey back, barred white underparts, and a black head. The peregrine is renowned for its speed, reaching over 320 km/h (200 mph) during its characteristic hunting stoop (high-speed dive), making it the fastest bird in the world, as well as the fastest member of the animal kingdom. According to a National Geographic TV program, the highest measured speed of a peregrine falcon is 389 km/h (242 mph). As is typical for bird-eating raptors, peregrine falcons are sexually dimorphic, with females being considerably larger than males. According to one study, it has the fastest visual processing speed of any animal tested so far, and can register discrete changes up to 129 Hz or cycles per second. Analogically, film is a series of still images projected onto a screen. Those still images need to be changing at roughly 24 frames per second before humans see them as fluid and no longer as individual, discrete pictures. The film would have to be refreshing at 129 frames per second before peregrine falcons stopped seeing flashing, still images and started seeing fluid motion.
The peregrine's breeding range includes land regions from the Arctic tundra to the tropics. It can be found nearly everywhere on Earth, except extreme polar regions, very high mountains, and most tropical rainforests; the only major ice-free landmass from which it is entirely absent is New Zealand. This makes it the world's most widespread raptor, and one of the most widely found bird species. In fact, the only land-based bird species found over a larger geographic area is not always naturally occurring, but one widely introduced by humans, the rock pigeon, which in turn now supports many peregrine populations as a prey species. The peregrine is a highly successful example of urban wildlife in much of its range, taking advantage of tall buildings as nest sites and an abundance of prey such as pigeons and ducks. Both the English and scientific names of this species mean "wandering falcon," referring to the migratory habits of many northern populations. Experts recognize 17 to 19 subspecies, which vary in appearance and range; disagreement exists over whether the distinctive Barbary falcon is represented by two subspecies of Falco peregrinus, or is a separate species, F. pelegrinoides. The two species' divergence is relatively recent, during the time of the last ice age, therefore the genetic differential between them (and also the difference in their appearance) is relatively tiny. They are only about 0.6–0.8% genetically differentiated.
Although its diet consists almost exclusively of medium-sized birds, the peregrine will occasionally hunt small mammals, small reptiles, or even insects. Reaching sexual maturity at one year, it mates for life and nests in a scrape, normally on cliff edges or, in recent times, on tall human-made structures. The peregrine falcon became an endangered species in many areas because of the widespread use of certain pesticides, especially DDT. Since the ban on DDT from the early 1970s, populations have recovered, supported by large-scale protection of nesting places and releases to the wild.
The peregrine falcon is a well-respected falconry bird due to its strong hunting ability, high trainability, versatility, and availability via captive breeding. It is effective on most game bird species, from small to large.
The peregrine falcon has a body length of 34 to 58 cm (13–23 in) and a wingspan from 74 to 120 cm (29–47 in). The male and female have similar markings and plumage, but as in many birds of prey the peregrine falcon displays marked sexual dimorphism in size, with the female measuring up to 30% larger than the male. Males weigh 330 to 1,000 g (0.73–2.20 lb) and the noticeably larger females weigh 700 to 1,500 g (1.5–3.3 lb). In most subspecies, males weigh less than 700 g (1.5 lb) and females weigh more than 800 g (1.8 lb), with cases of females weighing about 50% more than their male breeding mates not uncommon. The standard linear measurements of peregrines are: the wing chord measures 26.5 to 39 cm (10.4–15.4 in), the tail measures 13 to 19 cm (5.1–7.5 in) and the tarsus measures 4.5 to 5.6 cm (1.8–2.2 in).
The back and the long pointed wings of the adult are usually bluish black to slate grey with indistinct darker barring (see "Subspecies" below); the wingtips are black. The white to rusty underparts are barred with thin clean bands of dark brown or black. The tail, coloured like the back but with thin clean bars, is long, narrow, and rounded at the end with a black tip and a white band at the very end. The top of the head and a "moustache" along the cheeks are black, contrasting sharply with the pale sides of the neck and white throat. The cere is yellow, as are the feet, and the beak and claws are black. The upper beak is notched near the tip, an adaptation which enables falcons to kill prey by severing the spinal column at the neck. The immature bird is much browner with streaked, rather than barred, underparts, and has a pale bluish cere and orbital ring.
Taxonomy and systematics
Falco peregrinus was first described under its current binomial name by English ornithologist Marmaduke Tunstall in his 1771 work Ornithologia Britannica. The scientific name Falco peregrinus is a Medieval Latin phrase that was used by Albertus Magnus in 1225. The specific name is taken from the fact that juvenile birds were taken while journeying to their breeding location rather than from the nest, as falcon nests were difficult to get at. The Latin term for falcon, falco, is related to falx, meaning "sickle", in reference to the silhouette of the falcon's long, pointed wings in flight.
The peregrine falcon belongs to a genus whose lineage includes the hierofalcons[note 1] and the prairie falcon (F. mexicanus). This lineage probably diverged from other falcons towards the end of the Late Miocene or in the Early Pliocene, about 5–8 million years ago (mya). As the peregrine-hierofalcon group includes both Old World and North American species, it is likely that the lineage originated in western Eurasia or Africa. Its relationship to other falcons is not clear, as the issue is complicated by widespread hybridization confounding mtDNA sequence analyses. For example, a genetic lineage of the saker falcon (F. cherrug) is known which originated from a male saker producing fertile young with a female peregrine ancestor, and the descendants further breeding with sakers.
Today, peregrines are regularly paired in captivity with other species such as the lanner falcon (F. biarmicus) to produce the "perilanner", a somewhat popular bird in falconry as it combines the peregrine's hunting skill with the lanner's hardiness, or the gyrfalcon to produce large, strikingly coloured birds for the use of falconers. As can be seen, the peregrine is still genetically close to the hierofalcons, though their lineages diverged in the Late Pliocene (maybe some 2.5–2 mya in the Gelasian).
Numerous subspecies of Falco peregrinus have been described, with 19 accepted by the 1994 Handbook of the Birds of the World, which considers the Barbary falcon of the Canary Islands and coastal North Africa to be two subspecies (pelegrinoides and babylonicus) of Falco peregrinus, rather than a distinct species, F. pelegrinoides. The following map shows the general ranges of these 19 subspecies
- Falco peregrinus anatum, described by Bonaparte in 1838, is known as the American peregrine falcon, or "duck hawk"; its scientific name means "duck peregrine falcon". At one time, it was partly included in leucogenys. It is mainly found in the Rocky Mountains today. It was formerly common throughout North America between the tundra and northern Mexico, where current reintroduction efforts seek to restore the population. Most mature anatum, except those that breed in more northern areas, winter in their breeding range. Most vagrants that reach western Europe seem to belong to the more northern and strongly migratory tundrius, only considered distinct since 1968. It is similar to peregrinus but is slightly smaller; adults are somewhat paler and less patterned below, but juveniles are darker and more patterned below. Males weigh 500 to 700 g (1.1–1.5 lb), while females weigh 800 to 1,100 g (1.8–2.4 lb). It has become extinct in eastern North America, and populations there are hybrids as a result of reintroductions of birds from elsewhere.
- Falco peregrinus babylonicus, described by P.L. Sclater in 1861, is found in eastern Iran along the Hindu Kush and Tian Shan to Mongolian Altai ranges. A few birds winter in northern and northwestern India, mainly in dry semi-desert habitats. It is paler than pelegrinoides, and somewhat similar to a small, pale lanner falcon (Falco biarmicus). Males weigh 330 to 400 grams (12 to 14 oz), while females weigh 513 to 765 grams (18.1 to 27.0 oz).
- Falco peregrinus brookei, described by Sharpe in 1873, is also known as the Mediterranean peregrine falcon or the Maltese falcon.[note 2] It includes caucasicus and most specimens of the proposed race punicus, though others may be pelegrinoides (Barbary falcons), or perhaps the rare hybrids between these two which might occur around Algeria. They occur from the Iberian Peninsula around the Mediterranean, except in arid regions, to the Caucasus. They are non-migratory. It is smaller than the nominate subspecies, and the underside usually has rusty hue. Males weigh around 445 g (0.981 lb), while females weigh up to 920 g (2.03 lb).
- Falco peregrinus calidus, described by John Latham in 1790, was formerly called leucogenys and includes caeruleiceps. It breeds in the Arctic tundra of Eurasia, from Murmansk Oblast to roughly Yana and Indigirka Rivers, Siberia. It is completely migratory, and travels south in winter as far as South Asia and sub-Saharan Africa. It is often seen around wetland habitats. It is paler than peregrinus, especially on the crown. Males weigh 588 to 740 g (1.296–1.631 lb), while females weigh 925 to 1,333 g (2.039–2.939 lb).
- Falco peregrinus cassini, described by Sharpe in 1873, is also known as the Austral peregrine falcon. It includes kreyenborgi, the pallid falcon,[note 3] a leucistic morph occurring in southernmost South America, which was long believed to be a distinct species. Its range includes South America from Ecuador through Bolivia, northern Argentina, and Chile to Tierra del Fuego and the Falkland Islands. It is non-migratory. It is similar to nominate, but slightly smaller with a black ear region. The variation kreyenborgi is medium grey above, has little barring below, and has a head pattern like the saker falcon, but the ear region is white.
- Falco peregrinus ernesti, described by Sharpe in 1894, is found from the Sunda Islands to Philippines and south to eastern New Guinea and the nearby Bismarck Archipelago. Its geographical separation from nesiotes requires confirmation. It is non-migratory. It differs from the nominate subspecies in the very dark, dense barring on its underside and its black ear coverts.
- Falco peregrinus furuitii, described by Momiyama in 1927, is found on the Izu and Ogasawara Islands south of Honshū, Japan. It is non-migratory. It is very rare, and may only remain on a single island. It is a dark form, resembling pealei in colour, but darker, especially on the tail.
- Falco peregrinus japonensis, described by Gmelin in 1788, includes kleinschmidti, pleskei, and harterti, and seems to refer to intergrades with calidus. It is found from northeast Siberia to Kamchatka (though it is possibly replaced by pealei on the coast there) and Japan. Northern populations are migratory, while those of Japan are resident. It is similar to peregrinus, but the young are even darker than those of anatum.
- Falco peregrinus macropus, described by Swainson in 1837, is the Australian peregrine falcon. It is found in Australia in all regions except the southwest. It is non-migratory. It is similar to brookei in appearance, but is slightly smaller and the ear region is entirely black. The feet are proportionally large.
- Falco peregrinus madens, described by Ripley and Watson in 1963, is unusual in having some sexual dichromatism. If the Barbary falcon (see below) is considered a distinct species, it is sometimes placed therein. It is found in the Cape Verde Islands, and is non-migratory; it is endangered with only six to eight pairs surviving. Males have a rufous wash on crown, nape, ears, and back; underside conspicuously washed pinkish-brown. Females are tinged rich brown overall, especially on the crown and nape.
- Falco peregrinus minor, first described by Bonaparte in 1850. It was formerly often known as perconfusus. It is sparsely and patchily distributed throughout much of sub-Saharan Africa and widespread in Southern Africa. It apparently reaches north along the Atlantic coast as far as Morocco. It is non-migratory and dark coloured. This is the smallest subspecies of peregrine, with smaller males weighing as little as approximately 300 g (11 oz).
- Falco peregrinus nesiotes, described by Mayr in 1941, is found in Fiji and probably also Vanuatu and New Caledonia. It is non-migratory.
- Falco peregrinus pealei, described by Ridgway in 1873, is also known as Peale's falcon, and includes rudolfi. It is found in the Pacific Northwest of North America, northwards from the Puget Sound along the British Columbia coast (including Haida Gwaii), along the Gulf of Alaska and the Aleutian Islands to the far eastern Bering Sea coast of Russia, and may also occur on the Kuril Islands and the coasts of Kamchatka. It is non-migratory. It is the largest subspecies, and it looks like an oversized and darker tundrius or like a strongly barred and large anatum. The bill is very wide. Juveniles occasionally have pale crowns. Males weigh 700 to 1,000 g (1.5–2.2 lb), while females weigh 1,000 to 1,500 g (2.2–3.3 lb).
- Falco peregrinus pelegrinoides, first described by Temminck in 1829, is found in the Canary Islands through North Africa and the Near East to Mesopotamia. It is most similar to brookei, but is markedly paler above, with a rusty neck, and is a light buff with reduced barring below. It is smaller than the nominate subspecies; females weigh around 610 g (1.34 lb).
- Falco peregrinus peregrinator, described by Sundevall in 1837, is known as the Indian peregrine falcon, black shaheen, Indian shaheen[note 4] or shaheen falcon. It was formerly sometimes known as Falco atriceps or Falco shaheen. Its range includes South Asia from across the Indian subcontinent to Sri Lanka and Southeastern China. In India, the shaheen is reported from all states except Uttar Pradesh, mainly from rocky and hilly regions. The Shaheen is also reported from the Andaman and Nicobar Islands in the Bay of Bengal. It has a clutch size of 3 to 4 eggs, with the chicks fledging time of 48 days with an average nesting success of 1.32 chicks per nest. In India, apart from nesting on cliffs, it has also been recorded as nesting on man-made structures such as buildings and cellphone transmission towers. A population estimate of 40 breeding pairs in Sri Lanka was made in 1996. It is non-migratory, and is small and dark, with rufous underparts. In Sri Lanka this species is found to favour the higher hills while the migrant calidus is more often seen along the coast.
- Falco peregrinus peregrinus, the nominate (first-named) subspecies, described by Tunstall in 1771, breeds over much of temperate Eurasia between the tundra in the north and the Pyrenees, Mediterranean region and Alpide belt in the south. It is mainly non-migratory in Europe, but migratory in Scandinavia and Asia. Males weigh 580 to 750 g (1.28–1.65 lb), while females weigh 925 to 1,300 g (2.039–2.866 lb). It includes brevirostris, germanicus, rhenanus, and riphaeus.
- Falco peregrinus radama, described by Hartlaub in 1861, is found in Madagascar and the Comoros. It is non-migratory.
- Falco peregrinus submelanogenys, described by Mathews in 1912, is the Southwest Australian peregrine falcon. It is found in southwest Australia and is non-migratory.
- Falco peregrinus tundrius, described by C.M. White in 1968, was at one time included in leucogenys. It is found in the Arctic tundra of North America to Greenland, and migrates to wintering grounds in Central and South America. Most vagrants that reach western Europe belong to this subspecies, which was previously united with anatum. It is the New World equivalent to calidus. It is smaller than anatum. It is also paler than anatum; most have a conspicuous white forehead and white in ear region, but the crown and "moustache" are very dark, unlike in calidus. Juveniles are browner, and less grey, than in calidus, and paler, sometimes almost sandy, than in anatum. Males weigh 500 to 700 g (1.1–1.5 lb), while females weigh 800 to 1,100 g (1.8–2.4 lb). Despite its current recognition as a valid subspecies, a population genetic study of both pre-decline (i.e., museum) and recovered contemporary populations failed to distinguish genetically the anatum and tundrius subspecies.
These birds inhabit arid regions from the Canary Islands along the rim of the Sahara through the Middle East to Central Asia and Mongolia.
Barbary falcons have a red neck patch but otherwise differ in appearance from the peregrine proper merely according to Gloger's Rule, relating pigmentation to environmental humidity. The Barbary falcon has a peculiar way of flying, beating only the outer part of its wings like fulmars sometimes do; this also occurs in the peregrine, but less often and far less pronounced. The Barbary falcon's shoulder and pelvis bones are stout by comparison with the peregrine, and its feet are smaller. Barbary falcons breed at different times of year than neighboring