Definitions

falcon

falcon

[fawl-kuhn, fal-, faw-kuhn]
falcon, common name for members of the Falconidae, a heterogeneous family of long-winged birds of prey closely related to the hawk. Falcons (genus Falco) range in size from the 61/2-in. (16.5-cm) falconet to the 24-in. (60-cm) gyrfalcon, and in habits from the swift merlin to the sluggish caracara. True falcons, distinguished by their notched beaks, are widely distributed. In flight their wingbeats are rapid and powerful, and they swoop hundreds of feet at speeds of up to 200 mph (320 kph) to capture their prey—chiefly birds and small mammals. They kill cleanly, usually breaking the back of their victim. Some falcons eat insects; the long-legged caracaras (found in South America, with one species, the crested, or Audubon's, caracara ranging to the extreme S United States) feed also on carrion and sometimes rob other birds of their prey. The cosmopolitan peregrine falcon and the gyrfalcon of the arctic tundra have been much used in falconry. The commonest and smallest American falcon is the American kestrel, or sparrow hawk, F. sparverius (related to the European kestrel). Others are the merlin, or pigeon hawk (related to the European merlin), and the prairie falcon. Falcons build no nests but lay their eggs on the ground, on cliff ledges, or in the abandoned nests of hawks and crows. Falcons are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Falconiformes.
or duck hawk

Peregrine falcon (Falco peregrinus).

Falcon species (Falco peregrinus) found worldwide but rare today because of bioaccumulation of pesticides. Peregrines are 13–19 in. (33–48 cm) long and gray above, with black-barred whitish underparts. They fly high and dive at tremendous speed (up to 175 mph, or 280 kph—the greatest speeds attained by any bird), striking with clenched talons and killing by impact. They usually nest in a scrape on a high cliff ledge near water, where bird prey is plentiful. Breeding programs have reintroduced the species into the wild and introduced it into urban areas, where it finds a clifflike habitat among skyscrapers and preys chiefly on the rock dove (see pigeon). Despite the programs' success, the species remains vulnerable.

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Any of nearly 60 species of diurnal birds of prey in the family Falconidae, characterized by long, pointed wings and swift, powerful flight. The name is sometimes restricted to the more than 35 species of true falcons, genus Falco. Species range from 6 to 24 in. (15–60 cm) long. Females of the genus Falco are larger and bolder than males and are preferred for falconry. Falcons, found worldwide, commonly nest in treeholes or on cliff ledges. Some species capture birds in midair; others live on hares, mice, lizards, and insects. Seealso gyrfalcon, hawk, kestrel, merlin, peregrine falcon.

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(born June 6, 1868, Devonport, Devon, Eng.—died circa March 29, 1912, Antarctica) British explorer. He joined the Royal Navy in 1880, proved his competence leading an Antarctic expedition (1901–04), and was promoted to captain. In 1910 he embarked on a second expedition, and in October 1911 he and 11 others started overland for the South Pole. After their motor sledges broke down and seven men returned to base camp, Scott and four others trekked for 81 days to reach the pole in January 1912, only to find that Roald Amundsen had preceded them by about a month. Exhausted and beset by bad weather and insufficient supplies, the men died on the return trip, Scott and the last two survivors only 11 miles from their base camp. In England Scott was celebrated as a national hero for his courage, though his judgment has been questioned.

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(born June 6, 1868, Devonport, Devon, Eng.—died circa March 29, 1912, Antarctica) British explorer. He joined the Royal Navy in 1880, proved his competence leading an Antarctic expedition (1901–04), and was promoted to captain. In 1910 he embarked on a second expedition, and in October 1911 he and 11 others started overland for the South Pole. After their motor sledges broke down and seven men returned to base camp, Scott and four others trekked for 81 days to reach the pole in January 1912, only to find that Roald Amundsen had preceded them by about a month. Exhausted and beset by bad weather and insufficient supplies, the men died on the return trip, Scott and the last two survivors only 11 miles from their base camp. In England Scott was celebrated as a national hero for his courage, though his judgment has been questioned.

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A falcon (fɔlkən or fælkən) is any species of raptor in the genus Falco. The word comes from their Latin name falco, related to Latin falx ("sickle") because of the shape of these birds' wings.

Overview

Adult falcons have thin tapered wings, which enable them to fly at high speed and to change direction rapidly. Fledgling falcons, in their first year of flying, have longer flight feathers which makes their configuration more like that of a general-purpose bird such as a broadwing. This is to make it easier for them to fly while learning the exceptional skills required to be effective hunters in their adult configuration. A falcon's wings are shaped like a scythe. Although common misconceptions of the difference of a scythe and sickle are the cause of the misconception of the shape of the falcons wings.

Peregrine Falcons are the fastest-moving creatures on Earth. Other falcons include the Gyrfalcon, Lanner Falcon, and the Merlin. Some small insectivorous falcons with long narrow wings are called hobbies, and some which hover while hunting for small rodents are called kestrels. The falcons are part of the family Falconidae, which also includes the caracaras, Laughing Falcon, forest falcons, and falconets.

The traditional term for a male falcon is tercel (UK spelling) or tiercel (US spelling), from 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 approximately one third smaller than the female (Old French tiercelet).

A falcon chick, especially one reared for falconry, that is still in its downy stage is known as an eyas (sometimes spelt 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.

As is the case with many birds of prey, falcons are renowned for their exceptional powers of vision; one species has been found to have a visual acuity of 2.6 times that of a normal human.

In February 2005, the Canadian ornithologist Louis Lefebvre announced a method of measuring avian intelligence in terms of their innovation in feeding habits. The falcon and crow family scored highest on this scale.

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. 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 and given the distribution of fossil and living Falco taxa is probably of North American, African or possibly Middle Eastern or European in origin.

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 color and sometimes sexually dimorphic; three African species that are generally grey 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) and more elegant species, the hobbies and relatives. These birds are characterized by considerable amounts of dark slaty grey in their plumage; the malar area is nearly always black. They feed mainly on smaller birds.

Third are the Falcon and its relatives: powerful birds, often the size of small hawks, they also have a black malar area (except some very light color morphs), and often a black cap also. Otherwise, they are somewhat intermediate between the other groups, being chiefly medium grey with some lighter or brownish colours on the upper side. They are on average more delicately patterned than the hobbies and if the hierofalcons are excluded (see below), this group contains typically species with horizontal barring on the underside. As opposed to the other groups, where tail colour varies much in general but little according to evolutionary relatedness, the tails of the large falcons are quite uniformly dark grey with rather inconspicuous black banding and small white tips, though this is probably plesiomorphic. These large Falco feed on mid-sized birds and terrestrial vertebrates, taking prey of up to 5-pound sage grouse size.

Very similar to these and sometimes included therein are the 4 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. Notably, 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 (Groombridge et al. 2002) 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. The latter species has a malar stripe, but its color pattern - apart from the brownish back - and notably 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 2.5-2 mya, and are apparently 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.

Other studies have confirmed that the hierofalcons are a monophyletic group - and, incidentally, that hybridization is quite frequent at least in the larger species falcon species. Initial studies of mtDNA cytochrome b sequence data suggested that the hierofalcons are basal among living falcons. This is now known to be an erroneous result due to the presence of a numt (Wink & Sauer-Gürth 2000); in reality the hierofalcons are a rather young group, originating maybe at the same time as the start of the main kestrel radiaton, about 2 million years ago. This lineage seems to have gone nearly extinct at some point in the past; the present diversity is of very recent origin, though little is known about their fossil history (Nittinger et al. 2005, Johnson et al. 2007).

The phylogeny and delimitations of the Peregrine and hobbies groups is more problematic. Molecular studies have only been conducted on a few species, and namely 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, 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, even though it is entirely distinct biogeographically), as well as at least most of the "typical" hobbies, are confirmed to be monophyletic as suspected.

Given that the American Falcos of today belong to the Peregrine group or are apparently more basal species, it seems that the initially most successful evolutionary radiation was an 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.

In conclusion, the origin of today's major Falco groups - the "typical" hobbies and kestrels for example, or the Peregine-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 about 8 to 2.4 million years ago, when the malar-striped kestrels diversified. Some groups of falcons, such as the hierofalcon complex or the Peregrine-Barbary superspecies have only evolved in more recent times; the species of the former seem to be a mere 120.000 years old or so (Nittinger et al. 2005).

Species

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

Fossil record

  • Falco medius (Late Miocene of Cherevichnyi, Ukraine)
  • ?Falco sp. (Late Miocene of Idaho)
  • Falco sp. (Early Pliocene of Kansas)
  • Falco sp. (Early Pliocene of Bulgaria - Early Pleistocene of Spain and Czechia)
  • 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)
  • Cuban Kestrel, Falco kurochkini (Late Pleistocene/Holocene of Cuba, West Indies)
  • Falco chowi (China)

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 into this genus or a closely related one (Becker 1987). In any case, the genus name Sushkinia is invalid for this animal because it had already been allocated to a prehistoric dragonfly relative.

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" (Mlíkovský 2002). 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 into this genus. "Falco" readei is now considered a paleosubspecies of the Yellow-headed Caracara (Milvago chimachima).

Footnotes

References

  • (1987): Revision of "Falco" ramenta Wetmore and the Neogene evolution of the Falconidae. Auk 104(2): 270-276. PDF fulltext
  • (1970): Some birds of prey from the Upper Pliocene of Kansas. Auk 87(4): 795-797. PDF fulltext
  • (1999): Phylogeny of the Falconidae inferred from molecular and morphological data. Auk 116(1): 116–130. PDF fulltext
  • (2004): Phylogeny of the Falconidae (Aves): a comparison of the efficacy of morphological, mitochondrial, and nuclear data. Molecular Phylogenetics and Evolution 32(1): 101–109. (HTML abstract)
  • (2002): A molecular phylogeny of African kestrels with reference to divergence across the Indian Ocean. Molecular Phylogenetics and Evolution 25(2): 267–277. (HTML abstract)
  • (1994): Phylogenetic relationships among falcon species (genus Falco) according to DNA sequence variation of the cytochrome b gene. In: : Raptor conservation today: 593-599. PDF fulltext
  • (2007): Genetic structure among continental and island populations of gyrfalcons. Molecular Ecology 16:3145-3160. (HTML abstract)
  • (2000): The Meade Basin Rodent Project; a progress report. Kansas Geologial Survey Open-file Report 2000-61. Paludicola 3(1): 1-32.
  • (2002): Cenozoic Birds of the World, Part 1: Europe. Ninox Press, Prague. ISBN 80-901105-3-8 PDF fulltext
  • (2005): Out of Africa? Phylogenetic relationships between Falco biarmicus and other hierofalcons (Aves Falconidae). Journal of Zoological Systematics and Evolutionary Research 43(4): 321-331. PDF fulltext
  • (2003): Новый вид плиоценового сокола (Falconiformes, Falconidae) [A new species of Pliocene falcon (Falconiformes, Falconidae)] Vestnik zoologii 37(6): 85–87. [Russian with English abstract] PDF fulltext
  • (1994): Family Falconidae. In: (editors): Handbook of Birds of the World, Volume 2 (New World Vultures to Guineafowl): 216-275, plates 24-28. Lynx Edicions, Barcelona. ISBN 84-87334-15-6
  • (2000): Advances in the molecular systematics of African raptors. In: : Raptors at Risk: 135-147. WWGBP/Hancock House, Berlin/Blaine. PDF fulltext
  • (1998): Molecular systematics of holarctic raptors (Order Falconiformes). In: : Holarctic Birds of Prey: 29-48. Adenex & WWGBP. PDF fulltext
  • (2004): Phylogenetic relationships in the Hierofalco complex (Saker-, Gyr-, Lanner-, Laggar Falcon). In: : Raptors Worldwide: 499-504. WWGBP, Berlin. PDF fulltext

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