Falcons () are

birds of prey Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...

in the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Falco'', which includes about 40

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

. Some small species of falcons with long, narrow

wing A wing is a type of fin that produces both Lift (force), lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform (aeronautics), planform. Wing efficiency is expressed as lift-to-d ...

s are called hobbies, and some that hover while hunting are called kestrels. Falcons are widely distributed on all continents of the world except

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

, though closely related raptors did occur there in the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

. 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 broadwing. This makes flying easier while still learning the aerial skills required to be effective hunters like the adults. The falcons are the largest genus in the Falconinae

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

of Falconidae, which also includes two other subfamilies comprising caracaras and a few other species of "falcons". All these birds kill prey with their beaks, using a tomial "tooth" on the side of their beaks—unlike the hawks,

eagle Eagle is the common name for the golden eagle, bald eagle, and other birds of prey in the family of the Accipitridae. Eagles belong to several groups of Genus, genera, some of which are closely related. True eagles comprise the genus ''Aquila ( ...

s and other larger birds of prey from the unrelated family Accipitridae, who use talons on their feet. The largest falcon is the

gyrfalcon The gyrfalcon ( or ) (), 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, ...

at up to in length. The smallest falcon species is the pygmy falcon, which measures just . As with hawks and owls, falcons exhibit

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

, with the females typically larger than the males, thus allowing a wider range of prey species. As is the case with many birds of prey, falcons have exceptional powers of

vision Vision, Visions, or The Vision may refer to: Perception Optical perception * Visual perception, the sense of sight * Visual system, the physical mechanism of eyesight * Computer vision, a field dealing with how computers can be made to gain und ...

; the visual acuity of one species has been measured at 2.6 times that of human eyes. They are fast fliers, with the Peregrine falcons having been recorded diving at speeds of , making them the fastest-moving creatures on Earth; the fastest recorded dive attained a vertical speed of .

Taxonomy

The

''Falco'' was introduced in 1758 by the Swedish naturalist

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

in the tenth edition of his ''

Systema Naturae ' (originally in Latin written ' with the Orthographic ligature, ligature æ) is one of the major works of the Sweden, Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the syste ...

''. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

is the merlin (''Falco columbarius''). The genus name is

Late Latin Late Latin is the scholarly name for the form of Literary Latin of late antiquity.Roberts (1996), p. 537. English dictionary definitions of Late Latin date this period from the 3rd to 6th centuries CE, and continuing into the 7th century in ...

meaning a "falcon" from , , meaning "a sickle", referring to the claws of the bird. In

Middle English Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman Conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English pe ...

and

Old French Old French (, , ; ) was the language spoken in most of the northern half of France approximately between the late 8th The traditional term for a male falcon is ''tercel'' ( British spelling) or ''tiercel'' (American English">American spelling), from the Latin (3 (number)">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 (). A falcon chick, especially one reared for falconry, still in its downy stage, is known as an ''eyas'' (sometimes spelled ''eyass''). The word arose by mistaken division of

Old French Old French (, , ; ) was the language spoken in most of the northern half of France approximately between the late 8th -4; we might wonder whether there's a point at which it's appropriate to talk of the beginnings of French, that is, when it wa ...

, from Latin presumed (nestling) from (nest). The technique of hunting with trained captive birds of prey is known as falconry. Compared to other birds of prey, the fossil record of the falcons is not well distributed in time. For years, the oldest fossils tentatively assigned to this genus were from the Late

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

, less than 10 million years ago. This coincides with a period in which many modern genera of birds became recognizable in the fossil record. As of 2021, the oldest falconid fossil is estimated to be 55 million years old. Given the distribution of fossil and living ''Falco'' taxa, falcons are 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.

Overview

Falcons are roughly divisible into three or four groups. The first contains the kestrels (probably excepting the American kestrel); usually small and stocky falcons of mainly brown upperside colour and sometimes sexually dimorphic; three African species that are generally gray in colour stand apart from the typical members of this group. The fox and greater kestrels can be told apart at first glance by their tail colours, 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. Kestrels feed chiefly on terrestrial

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

s and invertebrates of appropriate size, such as

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

s, or

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s. 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. They are very fast birds with a maximum speed of 390 kilometres per hour. Otherwise, they are somewhat intermediate between the other groups, being chiefly medium grey with some lighter or brownish colours 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 colour varies much in general but little according to

evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

ary relatedness,For example, tail colour in the

common Common may refer to: As an Irish surname, it is anglicised from Irish Gaelic surname Ó Comáin. Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common, a central public park in Boston, Massachusetts * Cambridge Com ...

and lesser kestrels is absolutely identical, yet they do not seem closely related. the tails of the large falcons are quite uniformly dark grey with inconspicuous black banding and small, white tips, though this is probably

plesiomorph In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral Phenotypic trait, character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorph ...

ic. 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 hierofalcon (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

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

s in their entirety. A study of mtDNA cytochrome ''b''

sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is cal ...

data of some kestrels 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 colour 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

, as also suggested by their numerous apomorphies. FalconHeadBeak

Other studies have confirmed that the hierofalcon are a

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

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 hierofalcon are basal among living falcons. The discovery of a NUMT proved this earlier theory erroneous. In reality, the hierofalcon 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. The phylogeny and delimitations of the peregrine and hobby 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 A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or Taxon, taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, M ...

of the Falconidae, is not very informative in the present genus. Nonetheless, a core group containing the peregrine and Barbary falcons, which, in turn, group with the hierofalcon and the more distant prairie falcon (which was sometimes placed with the hierofalcon, though it is entirely distinct biogeographically), as well as at least most of the "typical" hobbies, are confirmed to be

as suspected. 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

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Zanclean and

Piacenzian The Piacenzian is in the international geologic time scale the upper stage (stratigraphy), stage or latest age (geology), age of the Pliocene. It spans the time between 3.6 ± 0.005 year#SI prefix multipliers, Ma and 2.58 Ma (million years ago). T ...

and just into the Gelasian, that is from 2.4 to 5.3 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.

Species

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

Extinct species

* Réunion kestrel, ''Falco duboisi'' –

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

(about 1700)

Fossil record

*'' Falco medius'' (Late Miocene of Cherevichnyi, Ukraine) 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 *''?Falco'' sp. (Late Miocene of Idaho) IMNH 27937. A coracoid of a merlin-sized species. It does not seem close to ''F. columbarius'' or the Recent North American species (Becker 1987). *''Falco'' sp. (Early Pliocene of Kansas) *''Falco'' sp. (Early Pliocene of Bulgaria – Early Pleistocene of Spain and Czech Republic)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). *'' Falco oregonus'' (Early/Middle Pliocene of Fossil Lake, Oregon) – possibly not distinct from a living species *'' Falco umanskajae'' (Late Pliocene of Kryzhanovka, Ukraine) – includes " Falco odessanus", a '' nomen nudum'' *''? Falco bakalovi'' (Late Pliocene of Varshets, Bulgaria) *'' Falco antiquus'' (Middle Pleistocene of Noailles, France and possibly Horvőlgy, Hungary)Supposedly a saker falcon paleosubspecies (Mlíkovský 2002), but this is not too likely due to the probable Eemian origin of that species. * Cuban kestrel, ''Falco kurochkini'' (Late Pleistocene/Holocene of Cuba, West Indies) * '' Falco chowi'' (China) *'' Falco bulgaricus'' (Late Miocene of Hadzhidimovo, Bulgaria) 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. 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''.Nikita V. Zelenkov; Evgeny N. Kurochkin (2015). "КЛАСС AVES". In E.N. Kurochkin; A.V. Lopatin; N.V. Zelenkov. Ископаемые позвоночные России и сопредельных стран. Ископаемые рептилии и птицы. Часть 3 / Fossil vertebrates of Russia and adjacent countries. Fossil Reptiles and Birds. Part 3. GEOS. pp. 86–290. . 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". The

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'').

Notes

References

External links

Falconidae videos
on the Internet Bird Collection, ibc.lynxeds.com
The Raptor Resource Project
– Peregrine, owl, eagle and osprey cams, facts, and other resources, raptorresource.org * {{Authority control Birds of prey Extant Miocene first appearances Falconry National symbols of Saudi Arabia Taxa named by Carl Linnaeus National symbols of Kuwait