Editing Falcon (section)

===Overview===
Falcons are roughly divisible into three or four groups. The first contains the [[kestrel]]s (probably excepting the [[American kestrel]]);<ref name=Groombridge/> 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 kestrel|fox]] and [[greater kestrel]]s 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 animal|terrestrial]] [[vertebrate]]s and [[invertebrate]]s of appropriate size, such as [[rodent]]s, [[reptile]]s, or [[insect]]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 [[Cheek|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 [[morph (zoology)|morph]]s), 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]]ary relatedness,<ref group=note>For example, tail colour in the [[common kestrel|common]] and [[lesser kestrel]]s is absolutely identical, yet they do not seem closely related.</ref> the tails of the large falcons are quite uniformly dark grey with inconspicuous black banding and small, white tips, though this is probably [[plesiomorph]]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 [[phaeomelanin]]s, which impart reddish or brown colors, and generally more strongly patterned plumage reminiscent of [[hawk]]s. 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]]s in their entirety.

A study of [[mtDNA]] [[cytochrome b|cytochrome ''b'']] [[DNA sequence|sequence]] data of some kestrels<ref name=Groombridge/> identified a clade containing the common kestrel and related "[[Cheek|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 [[clade]], as also suggested by their numerous [[apomorph]]ies.
[[File:FalconHeadBeak.png|thumb|Most members of the genus ''Falco'' show a "tooth" on the upper [[mandible]].]]
Other studies<ref name=Helbig/><ref name=Wink1998/><ref name=Wink2000/><ref name=Wink2004/><ref name=Nittinger/> have confirmed that the hierofalcon are a [[monophyly|monophyletic]] group–and that [[hybrid (biology)|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 (evolution)|basal]] among living falcons.<ref name=Helbig/><ref name=Wink1998/> The discovery of a [[Numt|NUMT]] proved this earlier theory erroneous.<ref name=Wink2000/> 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.<ref name=Nittinger/><ref name=Johnson/>

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 (biology)|morphology]] of the [[Syrinx (bird anatomy)|syrinx]], which contributes well to resolving the overall [[phylogeny]] of the [[Falconidae]],<ref name=Griffiths1999/><ref name=Griffiths2004/> 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 [[biogeographical]]ly), as well as at least most of the "typical" hobbies, are confirmed to be [[monophyly|monophyletic]] as suspected.<ref name=Helbig/><ref name=Wink1998/>

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 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.<ref name=Nittinger/>