Barbary Falcon
Encyclopedia
The Barbary Falcon is a medium-sized falcon
about the size of a crow
. This bird of prey
breeds in the Canary Islands
and on the coasts of north Africa
. It is mainly resident.
of semi-desert and dry open hills. It typically lays its eggs in cliff-ledge nests.
The Barbary Falcon is similar to the Peregrine Falcon
, but smaller at 33–39 cm length with a wingspan of 76–98 cm. The female is larger than the male. It resembles its relative in general structure.
Adults have paler grey-blue upperparts than the Peregrine, and often have a buff wash to the barred underparts, whereas the larger species has a white background colour. The nape is rufous, but this is difficult to see.
Sexes are similar, apart from size, but the young birds have brown upperparts and streaked underparts. The streaking is lighter than in the juvenile Peregrine.
The call is a high-pitched "rek-rek-rek".
. The genetic distance is slight and the species form a close-knit and somewhat paraphyletic group in DNA sequence analyses. They differ more in behavior, ecology and anatomy
than usual for conspecifics. They are able to produce fertile hybrids, but they are generally allopatric and only co-occur during breeding season in small areas around Punjab
, Khorasan
, and possibly the Maghreb
and the Mongolian Altai, and there is clear evidence of assortative mating
with hybridization hardly ever occurring under natural conditions. In short, though they occupy adjacent territories, they breed at different times of year and Barbary Falcons virtually never breed with Peregrines in nature.
Assuming a genetic distance of 2% in hierofalcons corresponds to a divergence roughly 200,000-130,000 years ago, the 0.6-0.7% genetic distance in the Peregine-Barbary Falcon ("peregrinoid") complex suggests its current taxa evolve
d in the Late Pleistocene
some 100,000 years ago or less, but before the Upper Paleolithic
. The presumed time of divergence between Peregrine and Barbary Falcons approximately coincides with the start of the last ice age, when desertification
was prominent in North Africa and the Middle East, and the Persian Gulf
became a landlocked inland sea that slowly dried up. Populations of ancestral "peregrinoid" falcons living in marginal habitat at the fringe of the African-Middle Eastern desert belt either adapted (and might have become isolated e.g. in the Persian Gulf region, which turned into semiarid habitat surrounded by vast deserts), or left for better habitat, or became extinct. During interstadials, deserts receded and the aridland and humidland populations could expand to contact again, causing some limited gene flow. This scenario by and large parallels the proposed evolutionary history of the Saker Falcon
in relation to the other hierofalcons; indeed, that group shows similar patterns of molecular paraphyly though it is of somewhat earlier origin.
The fossil record adds little to the issue. A humerus
some 9,000 years old (i.e., after the last ice age) from the Aswan
area in Sudan
, where Falco peregrinus minor occurs today, was identified to belong to the Peregrine. The Barbary Falcon is one of the rare cases that may arguably be considered a species under the Biological, but certainly not under the Phylogenetic Species Concept rather than the other way around as usual. This case demonstrates that what makes a "species" is not only its descent, but also occurs to a population in the course of evolution, how it adapts, and how this affects its reproductive isolation
(or lack thereof) from sister taxa.
Falcon
A falcon is any species of raptor in the genus Falco. The genus contains 37 species, widely distributed throughout Europe, Asia, and North America....
about the size of a crow
Crow
Crows form the genus Corvus in the family Corvidae. Ranging in size from the relatively small pigeon-size jackdaws to the Common Raven of the Holarctic region and Thick-billed Raven of the highlands of Ethiopia, the 40 or so members of this genus occur on all temperate continents and several...
. This bird of prey
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....
breeds in the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
and on the coasts of north Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
. It is mainly resident.
Description
It is a birdBird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
of semi-desert and dry open hills. It typically lays its eggs in cliff-ledge nests.
The Barbary Falcon is similar to the Peregrine Falcon
Peregrine Falcon
The Peregrine Falcon , also known as the Peregrine, and historically as the Duck Hawk in North America, is a widespread bird of prey in the family Falconidae. A large, crow-sized falcon, it has a blue-gray back, barred white underparts, and a black head and "moustache"...
, but smaller at 33–39 cm length with a wingspan of 76–98 cm. The female is larger than the male. It resembles its relative in general structure.
Adults have paler grey-blue upperparts than the Peregrine, and often have a buff wash to the barred underparts, whereas the larger species has a white background colour. The nape is rufous, but this is difficult to see.
Sexes are similar, apart from size, but the young birds have brown upperparts and streaked underparts. The streaking is lighter than in the juvenile Peregrine.
The call is a high-pitched "rek-rek-rek".
Taxonomy
The Barbary Falcon differ in appearance from the Peregrine Falcon according to Gloger's RuleGloger's rule
Gloger's Rule is a zoological rule which states that within a species of endotherms, more heavily pigmented forms tend to be found in more humid environments, e.g. near the equator. It was named after the zoologist Constantin Wilhelm Lambert Gloger, who first remarked upon this phenomenon in 1833...
. The genetic distance is slight and the species form a close-knit and somewhat paraphyletic group in DNA sequence analyses. They differ more in behavior, ecology and anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
than usual for conspecifics. They are able to produce fertile hybrids, but they are generally allopatric and only co-occur during breeding season in small areas around Punjab
Punjab region
The Punjab , also spelled Panjab |water]]s"), is a geographical region straddling the border between Pakistan and India which includes Punjab province in Pakistan and the states of the Punjab, Haryana, Himachal Pradesh, Chandigarh and some northern parts of the National Capital Territory of Delhi...
, Khorasan
Iran
Iran , officially the Islamic Republic of Iran , is a country in Southern and Western Asia. The name "Iran" has been in use natively since the Sassanian era and came into use internationally in 1935, before which the country was known to the Western world as Persia...
, and possibly the Maghreb
Maghreb
The Maghreb is the region of Northwest Africa, west of Egypt. It includes five countries: Morocco, Algeria, Tunisia, Libya, and Mauritania and the disputed territory of Western Sahara...
and the Mongolian Altai, and there is clear evidence of assortative mating
Assortative mating
Assortative mating , and the related concept Disassortative mating, is the phenomenon where a sexually reproducing organism chooses to mate with individuals that are similar or dissimilar to itself in some specific manner...
with hybridization hardly ever occurring under natural conditions. In short, though they occupy adjacent territories, they breed at different times of year and Barbary Falcons virtually never breed with Peregrines in nature.
Assuming a genetic distance of 2% in hierofalcons corresponds to a divergence roughly 200,000-130,000 years ago, the 0.6-0.7% genetic distance in the Peregine-Barbary Falcon ("peregrinoid") complex suggests its current taxa evolve
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
d in the Late Pleistocene
Late Pleistocene
The Late Pleistocene is a stage of the Pleistocene Epoch. The beginning of the stage is defined by the base of the Eemian interglacial phase before the final glacial episode of the Pleistocene 126,000 ± 5,000 years ago. The end of the stage is defined exactly at 10,000 Carbon-14 years BP...
some 100,000 years ago or less, but before the Upper Paleolithic
Upper Paleolithic
The Upper Paleolithic is the third and last subdivision of the Paleolithic or Old Stone Age as it is understood in Europe, Africa and Asia. Very broadly it dates to between 40,000 and 10,000 years ago, roughly coinciding with the appearance of behavioral modernity and before the advent of...
. The presumed time of divergence between Peregrine and Barbary Falcons approximately coincides with the start of the last ice age, when desertification
Desertification
Desertification is the degradation of land in drylands. Caused by a variety of factors, such as climate change and human activities, desertification is one of the most significant global environmental problems.-Definitions:...
was prominent in North Africa and the Middle East, and the Persian Gulf
Persian Gulf
The Persian Gulf, in Southwest Asia, is an extension of the Indian Ocean located between Iran and the Arabian Peninsula.The Persian Gulf was the focus of the 1980–1988 Iran-Iraq War, in which each side attacked the other's oil tankers...
became a landlocked inland sea that slowly dried up. Populations of ancestral "peregrinoid" falcons living in marginal habitat at the fringe of the African-Middle Eastern desert belt either adapted (and might have become isolated e.g. in the Persian Gulf region, which turned into semiarid habitat surrounded by vast deserts), or left for better habitat, or became extinct. During interstadials, deserts receded and the aridland and humidland populations could expand to contact again, causing some limited gene flow. This scenario by and large parallels the proposed evolutionary history of the Saker Falcon
Saker Falcon
The Saker Falcon is a very large falcon. This species breeds from eastern Europe eastwards across Asia 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...
in relation to the other hierofalcons; indeed, that group shows similar patterns of molecular paraphyly though it is of somewhat earlier origin.
The fossil record adds little to the issue. A humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
some 9,000 years old (i.e., after the last ice age) from the Aswan
Aswan
Aswan , formerly spelled Assuan, is a city in the south of Egypt, the capital of the Aswan Governorate.It stands on the east bank of the Nile at the first cataract and is a busy market and tourist centre...
area in Sudan
Sudan
Sudan , officially the Republic of the Sudan , is a country in North Africa, sometimes considered part of the Middle East politically. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the...
, where Falco peregrinus minor occurs today, was identified to belong to the Peregrine. The Barbary Falcon is one of the rare cases that may arguably be considered a species under the Biological, but certainly not under the Phylogenetic Species Concept rather than the other way around as usual. This case demonstrates that what makes a "species" is not only its descent, but also occurs to a population in the course of evolution, how it adapts, and how this affects its reproductive isolation
Reproductive isolation
The mechanisms of reproductive isolation or hybridization barriers are a collection of mechanisms, behaviors and physiological processes that prevent the members of two different species that cross or mate from producing offspring, or which ensure that any offspring that may be produced is not...
(or lack thereof) from sister taxa.