Falcon

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Falcon
Temporal range: Late Miocene to present.
Brown-Falcon,-Vic,-3.1.2008.jpg
Brown falcon (Falco berigora) in Victoria, Australia
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Falconiformes
Family: Falconidae
Subfamily: Falconinae
Genus: Falco
Linnaeus, 1758
Species

About 37; see text.

Synonyms

Falcons ( /ˈfɒlkən,ˈfɔːl-,ˈfæl-/ ) are birds of prey in the genus Falco, which includes about 40 species. Falcons are widely distributed on all continents of the world except Antarctica, though closely related raptors did occur there in the Eocene. [1]

Contents

Adult falcons have thin, tapered wings, which enable them to fly at high speed and change direction rapidly. Fledgling falcons, in their first year of flying, have longer flight feathers, which make their configuration more like that of a general-purpose bird such as a broad-wing. This makes flying easier while learning the exceptional skills required to be effective hunters as adults. There are many different types of falcon.

The falcons are the largest genus in the Falconinae subfamily of Falconidae, which itself also includes another subfamily comprising caracaras and a few other species. All these birds kill with their beaks, using a "tooth" on the side of their beaks—unlike the hawks, eagles, and other birds of prey in the Accipitridae, which use their feet.

The largest falcon is the gyrfalcon at up to 65 cm in length. The smallest falcons are the kestrels, of which the Seychelles kestrel measures just 25 cm. As with hawks and owls, falcons exhibit sexual dimorphism, with the females typically larger than the males, thus allowing a wider range of prey species. [2]

Some small falcons with long, narrow wings are called "hobbies" [3] and some which hover while hunting are called "kestrels". [3] [4]

As is the case with many birds of prey, falcons have exceptional powers of vision; the visual acuity of one species has been measured at 2.6 times that of a normal human. [5] Peregrine falcons have been recorded diving at speeds of 200 miles per hour (320 km/h), making them the fastest-moving creatures on Earth. The fastest recorded dive for one is 390 km/h. [6]

Etymology

The genus name Falco is from Late Latin falx, falcis, a sickle, referring to the claws of the bird. [7] The species name vespertinus is Latin for "of evening" from vesper, "evening". [8] In Middle English and Old French, the title faucon refers generically to several captive raptor species. [9]

The traditional term for a male falcon is tercel (British spelling) or tiercel (American spelling), from the Latin tertius (third) because of the belief that only one in three eggs hatched a male bird. Some sources give the etymology as deriving from the fact that a male falcon is about one-third smaller than a female [10] [11] [12] (Old French : tiercelet). A falcon chick, especially one reared for falconry, still in its downy stage, is known as an eyas [13] [14] (sometimes spelled eyass). The word arose by mistaken division of Old French un niais, from Latin presumed nidiscus (nestling) from nidus (nest). The technique of hunting with trained captive birds of prey is known as falconry.

Systematics and evolution

Compared to other birds of prey, the fossil record of the falcons is not well distributed in time. The oldest fossils tentatively assigned to this genus are from the Late Miocene, less than 10 million years ago.[ citation needed ] This coincides with a period in which many modern genera of birds became recognizable in the fossil record. The falcon lineage may, however, be somewhat older than this,[ citation needed ] and given the distribution of fossil and living Falco taxa, is probably of North American, African, or possibly Middle Eastern or European origin. Falcons are not closely related to other birds of prey, and their nearest relatives are parrots and songbirds. [15]

Overview

Falcons are roughly divisible into three or four groups. The first contains the kestrels (probably excepting the American kestrel); [9] usually small and stocky falcons of mainly brown upperside color and sometimes sexually dimorphic; three African species that are generally gray in color stand apart from the typical members of this group. Kestrels feed chiefly on terrestrial vertebrates and invertebrates of appropriate size, such as rodents, reptiles, or insects.

The second group contains slightly larger (on average) species, the hobbies and relatives. These birds are characterized by considerable amounts of dark slate-gray in their plumage; their malar areas are nearly always black. They feed mainly on smaller birds.

Third are the peregrine falcon and its relatives, variably sized powerful birds that also have a black malar area (except some very light color morphs), and often a black cap, as well. Otherwise, they are somewhat intermediate between the other groups, being chiefly medium gray with some lighter or brownish colors on their upper sides. They are, on average, more delicately patterned than the hobbies and, if the hierofalcons are excluded (see below), this group typically contains species with horizontal barring on their undersides. As opposed to the other groups, where tail color varies much in general but little according to evolutionary relatedness, [note 1] However, the fox and greater kestrels can be told apart at first glance by their tail colors, but not by much else; they might be very close relatives and are probably much closer to each other than the lesser and common kestrels. The tails of the large falcons are quite uniformly dark gray with inconspicuous black banding and small, white tips, though this is probably plesiomorphic. These large Falco species feed on mid-sized birds and terrestrial vertebrates.

Very similar to these, and sometimes included therein, are the four or so species of hierofalcons (literally, "hawk-falcons"). They represent taxa with, usually, more phaeomelanins, which impart reddish or brown colors, and generally more strongly patterned plumage reminiscent of hawks. Their undersides have a lengthwise pattern of blotches, lines, or arrowhead marks.

While these three or four groups, loosely circumscribed, are an informal arrangement, they probably contain several distinct clades in their entirety.

A study of mtDNA cytochrome b sequence data of some kestrels [9] identified a clade containing the common kestrel and related "malar-striped" species, to the exclusion of such taxa as the greater kestrel (which lacks a malar stripe), the lesser kestrel (which is very similar to the common, but also has no malar stripe), and the American kestrel, which has a malar stripe, but its color pattern–apart from the brownish back–and also the black feathers behind the ear, which never occur in the true kestrels, are more reminiscent of some hobbies. The malar-striped kestrels apparently split from their relatives in the Gelasian, roughly 2.0–2.5 million years ago (Mya), and are seemingly of tropical East African origin. The entire "true kestrel" group—excluding the American species—is probably a distinct and quite young clade, as also suggested by their numerous apomorphies.

Most members of the genus Falco show a "tooth" on the upper mandible FalconHeadBeak.png
Most members of the genus Falco show a "tooth" on the upper mandible

Other studies [16] [17] [18] [19] [20] have confirmed that the hierofalcons are a monophyletic group–and that hybridization is quite frequent at least in the larger falcon species. Initial studies of mtDNA cytochrome b sequence data suggested that the hierofalcons are basal among living falcons. [16] [17] The discovery of a NUMT proved this earlier theory erroneous. [18] In reality, the hierofalcons are a rather young group, originating at the same time as the start of the main kestrel radiation, about 2 Mya. Very little fossil history exists for this lineage. However, the present diversity of very recent origin suggests that this lineage may have nearly gone extinct in the recent past. [20] [21]

The phylogeny and delimitations of the peregrine and hobbies groups are more problematic. Molecular studies have only been conducted on a few species, and the morphologically ambiguous taxa have often been little researched. The morphology of the syrinx, which contributes well to resolving the overall phylogeny of the Falconidae, [22] [23] is not very informative in the present genus. Nonetheless, a core group containing the peregrine and Barbary falcons, which, in turn, group with the hierofalcons and the more distant prairie falcon (which was sometimes placed with the hierofalcons, though it is entirely distinct biogeographically), as well as at least most of the "typical" hobbies, are confirmed to be monophyletic as suspected. [16] [17]

Given that the American Falco species of today belong to the peregrine group, or are apparently more basal species, the initially most successful evolutionary radiation seemingly was a Holarctic one that originated possibly around central Eurasia or in (northern) Africa. One or several lineages were present in North America by the Early Pliocene at latest.

The origin of today's major Falco groups—the "typical" hobbies and kestrels, for example, or the peregrine-hierofalcon complex, or the aplomado falcon lineage—can be quite confidently placed from the Miocene-Pliocene boundary through the Zanclean and Piacenzian and just into the Gelasian, that is from 2.4–8.0 Mya, when the malar-striped kestrels diversified. Some groups of falcons, such as the hierofalcon complex and the peregrine-Barbary superspecies, have only evolved in more recent times; the species of the former seem to be 120,000 years old or so. [20]

Species

Common kestrel Common Kestrel 1.jpg
Common kestrel
New Zealand falcon NZ Falcon 2006-01-14.jpg
New Zealand falcon
Saker falcon, a typical hierofalcon Falco cherrug Qatar.jpg
Saker falcon, a typical hierofalcon

The sequence follows the taxonomic order of White et al. (1996), [24] except for adjustments in the kestrel sequence.

Fossil record

Several more paleosubspecies of extant species also been described; see species accounts for these.

"Sushkinia" pliocaena from the Early Pliocene of Pavlodar (Kazakhstan) appears to be a falcon of some sort. It might belong in this genus or a closely related one. [25] In any case, the genus name Sushkinia is invalid for this animal because it had already been allocated to a prehistoric dragonfly relative. In 2015 the bird genus was renamed Psushkinia . [34]

The supposed "Falco" pisanus was actually a pigeon of the genus Columba , possibly the same as Columba omnisanctorum, which, in that case, would adopt the older species name of the "falcon". [26] The Eocene fossil "Falco" falconellus (or "F." falconella) from Wyoming is a bird of uncertain affiliations, maybe a falconid, maybe not; it certainly does not belong in this genus. "Falco" readei is now considered a paleosubspecies of the yellow-headed caracara (Milvago chimachima).

See also

Notes

  1. For example, tail color in the common and lesser kestrels is absolutely identical, yet they do not seem closely related.
  2. IZAN 45-4033: left carpometacarpus. Small species; possibly closer to kestrels than to peregrine lineage or hierofalcons, but may be more basal altogether due to its age
  3. A hierofalcon (Mlíkovský 2002)? If so, probably not close to the living species, but an earlier divergence that left no descendants; might be more than one species due to large range in time and/or include common ancestor of hierofalcons and peregrine-Barbary complex (Nittinger et al. 2005).
  4. Supposedly a saker falcon paleosubspecies (Mlíkovský 2002), but this is not too likely due to the probable Eemian origin of that species.

Related Research Articles

Bird of prey any species of bird that primarily hunt and feed on relatively large vertebrates

Birds of prey or raptors include species of bird that primarily hunt and feed on vertebrates that are large relative to the hunter. Additionally, they have keen eyesight for detecting food at a distance or during flight, strong feet equipped with talons for grasping or killing prey, and powerful, curved beaks for tearing flesh. The term raptor is derived from the Latin word rapio, meaning to seize or take by force. In addition to hunting live prey, most also eat carrion, at least occasionally, and vultures and condors eat carrion as their main food source.

Falconidae family of birds

The falcons and caracaras are around 60 species of diurnal birds of prey that make up the order Falconiformes. The family is divided into two subfamilies, Polyborinae, which includes the caracaras and forest falcons, and Falconinae, the falcons, kestrels and falconets.

Peregrine falcon cosmopolitan species of falconid raptor

The peregrine falcon, 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, 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.

Merlin (bird) species of bird

The merlin is a small species of falcon from the Northern Hemisphere, with numerous subspecies throughout North America and Eurasia. A bird of prey once known colloquially as a pigeon hawk in North America, the merlin breeds in the northern Holarctic; some migrate to subtropical and northern tropical regions in winter. Males typically have wingspans of 53–58 centimetres (21–23 in), with females being slightly larger. They are swift fliers and skilled hunters who specialize in preying on small birds in the size range of sparrows to quail. The merlin has for centuries been well regarded as a falconry bird. In recent decades merlin populations in North America have been significantly increasing, with some merlins becoming so well adapted to city life that they forgo migration.

Hobby (bird) type of falcon

A hobby is a fairly small, very swift falcon with long, narrow wings. There are four birds called "hobby", and some others which, although termed "falcon", are very similar. All specialise in being superb aerialists. Although they take prey on the ground if the opportunity presents itself, most prey is caught on the wing; insects are often caught by hawking, and many different birds are caught in flight, where even the quick maneuvering swifts and swallows cannot escape a hobby.

Eurasian hobby species of falcon

The Eurasian hobby, or just simply hobby, is a small, slim falcon. It belongs to a rather close-knit group of similar falcons often considered a subgenus Hypotriorchis.

American kestrel North American falcon species

The American kestrel is the smallest and most common falcon in North America. It has a roughly two-to-one range in size over subspecies and sex, varying in size from about the weight of a blue jay to a mourning dove. It also ranges to South America, and is a well-established species that has evolved seventeen subspecies adapted to different environments and habitats throughout the Americas. It exhibits sexual dimorphism in size and plumage, although both sexes have a rufous back with noticeable barring. Its plumage is colorful and attractive, and juveniles are similar in plumage to adults.

Lanner falcon Bird of prey

The lanner falcon is a medium-sized bird of prey that breeds in Africa, southeast Europe and just into Asia. It prefers open habitat and is mainly resident, but some birds disperse more widely after the breeding season. A large falcon, it preys on birds and bats.

Barbary falcon species of bird

The Barbary falcon is a medium-sized falcon about the size of a crow. This bird of prey is mainly resident.

Saker falcon species of bird

The saker falcon is a large species of falcon. This species breeds from central Europe eastwards across the Palearctic to Manchuria. It is mainly migratory except in the southernmost parts of its range, wintering in Ethiopia, the Arabian peninsula, northern Pakistan and western China. The Saker falcon is the national bird of Hungary and Mongolia.

Bat falcon species of falcon

The bat falcon is a falcon that is a resident breeder in tropical Mexico, Central and South America, and Trinidad. It was long known as Falco albigularis; the names Falco fusco-coerulescens or Falco fuscocaerulescens, long used for the aplomado falcon, are now believed to refer to the present species.

Prairie falcon falcon species

The prairie falcon is a medium-large sized falcon of western North America. It is about the size of a peregrine falcon or a crow, with an average length of 40 cm (16 in), wingspan of approximately 1 meter (40 in), and average weight of 720 g (1.6 lb). As in all falcons, females are noticeably bigger than males. Though a separate species from the peregrine, the prairie falcon is basically an arid environment adaptation of the early peregrine falcon lineage, able to subsist on less food than the peregrine, and generally lighter in weight than a peregrine of similar wing span. Having evolved in a harsh desert environment with low prey density, the prairie falcon has developed into an aggressive and opportunistic hunter of a wide range of both mammal and bird prey. It will regularly take prey from the size of sparrows to approximately its own weight, and occasionally much larger. It is the only larger falcon native only to North America. It is resident from southern Canada, through western United States, and into northern Mexico. The prairie falcon is popular as a falconry bird, where with proper training it is regarded as being as effective as the more well known peregrine falcon.

Aplomado falcon species of falcon

The aplomado falcon is a medium-sized falcon of the Americas. The species' largest contiguous range is in South America, but not in the deep interior Amazon Basin. It was long known as Falco fusco-coerulescens or Falco fuscocaerulescens, but these names are now believed to refer to the bat falcon. Its resemblance in shape to the hobbies accounts for its old name orange-chested hobby. Aplomado is an unusual Spanish word for "lead-colored", referring to the blue-grey areas of the plumage – an approximate English translation would be "plumbeous falcon". Spanish names for the species include halcón aplomado and halcón fajado ; in Brazil it is known as falcão-de-coleira.

Orange-breasted falcon falcon species of the Americas

The orange-breasted falcon is a bird of the falcon family. It is probably closely related to and looks like a larger version of the bat falcon. These two, in turn, are probably closest to the aplomado falcon and constitute a rather old American lineage of Falco.

Laggar falcon falcon from Asia

The laggar falcon, also known as the jugger is a mid-sized bird of prey which occurs in the Indian subcontinent from extreme southeastern Iran, southeastern Afghanistan, Pakistan, through India, Nepal, Bhutan, Bangladesh and northwestern Myanmar.

The name kestrel is given to several members of the falcon genus, Falco. Kestrels are most easily distinguished by their typical hunting behaviour which is to hover at a height of around 10–20 metres (35–65 ft) over open country and swoop down on prey, usually small mammals, lizards or large insects. Other falcons are more adapted to active hunting in flight. Kestrels are notable for usually having mostly brown in their plumage.

Australian hobby species of falcon

The Australian hobby, also known as the little falcon, is one of six Australian members of the family Falconidae. This predominately diurnal bird of prey derives its name ‘longipennis’ from its long primary wing feathers. It occurs throughout Australia and other neighbouring countries with migrating individuals found on the islands of Indonesia and New Guinea

Hierofalcon subgenus of birds

The hierofalcons are four closely related species of falcon which make up the subgenus Hierofalco:

References

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Further reading