Pied Raven
Encyclopedia
The Pied Raven was a colour morph of the North Atlantic subspecies
of the Common Raven
which was only found on the Faroe Islands
and has disappeared
since the mid twentieth century. It had large areas of white feathering, most frequently on the head, the wings and the belly, and its beak was light brown. Apart from that, it looked like the black birds (morpha typicus).
In modern Faroese
, the bird was called hvítravnur ("White Raven"), older name gorpur bringu hvíti ("White-chested Corbie"). Normal individuals of the subspecies
varius, which is found on Iceland
and the Faroe Islands, already show a tendency towards more extensive white feather
bases compared with the nominate subspecies. But only on the Faroes, a mutation
in the melanin
metabolism
would become fixed in the population, causing some birds to have about half of their feathers entirely white. While albinotic specimens sometimes occur in bird populations, the Pied Raven seems not to have been based on such occasional "sports", but on a constantly or at least regularly present part of the local raven population.
As these birds freely interacted and interbred with the black ones which are still found on the islands, they did not constitute a distinct subspecies. However, they illustrate two aspects of population genetics: genetic drift
, which in small populations will shift allele
frequencies over time (in this case, causing the occasionally occurring mutation to spread and become a permanent part of the gene pool
of ravens on the Faroes), and how a new, distinct subspecies may evolve
over time from a distinct part of the population. Had the black and pied ravens mated preferentially
with their own morph, in time the pied part of the population might have prevailed, as its coloration probably would have provided better camouflage
when preying on seabirds (most of which are also black-and-white).
The first record of the Pied Raven seems to be in the pre-1500 kvæði
Fuglakvæði eldra ("The elder ballad of birds") which mentions 40 local species, including the Great Auk
. Later, the Pied Raven is mentioned in the reports of Lucas Debes
(1673) and Jens Christian Svabo
(1781/82). Carl Julian von Graba in 1828 speaks of ten individuals he saw himself and states that these birds, while less numerous than the black morph, were quite common.
Díðrikur á Skarvanesi
, the first Faroe painter, painted the Fuglar series, a number of portrayal of birds. On his 18 fuglar ("18 birds"), the animal in the lower right corner can be identified as a Pied Raven. The painting is currently on display in the Listaskálin museum of Faroe art in Tórshavn
.
As exemplified by Skarvanesi's painting, which obviously was done from stuffed birds, the Pied Raven was an object of interest to collectors. During the nineteenth century, the pied birds were selectively shot because they could fetch high prices; the sýslumaður (sherriff) of Streymoy
, Hans Christopher Müller once paid two Danish rigsdaler
for a stuffed specimen from Nólsoy
. Such sums, a healthy amount of money for the impoverished Faroe farmers, made shooting a Pied Raven a profitable enterprise. Additionally, ravens in general were hunted as pests. In the mid nineteenth century, every Faroe male of hunting age was ordered by royal decree to shoot at least one raven or two other predatory birds per year or be fined four skilling
s. One of the last Pied Raven specimens was shot on November 2, 1902 on Mykines
. In the autumn of 1916, another bird was seen at Velbastaður
and on Koltur
. The last known individual was found in the winter of 1947 on Nólsoy, and disappeared late in 1948. As these last sightings raised widespread interest, it seems probable that after 1948, no Pied Raven has been seen.
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The Pied Raven, being a colour variation, only differed in one or very few alleles (as opposed to numerous genes in a true subspecies) from the black birds. The "piebald" allele(s) was or were recessive
or (if more than one) only caused the novel coloration if they were all present. This is evidenced by the last sightings which occurred in the absence of a regular breeding population of piebald birds, and the observations of H. C. Müller. Thus, it is not certain that the form is indeed extinct, if one can speak of "extinction" in any but a population genetical
sense anyway. Theoretically, the allele(s) could still be present but hidden in black individuals of the subspecies and thus, a Pied Raven could once again be born one day. As the raven population on the Faroes has declined to a few hundred birds at best over the recent decades, this does not seem very likely.
Today, 15 museum specimens of the Pied Raven are known: Six in Copenhagen
(Zoologisk Museum), four in New York
, two in Uppsala
, one in Leiden, one in Braunschweig
(Naturhistorisches Museum) and one in Dresden
. On June 12, 1995, the Postverk Føroya
issued the postal stamp FR 276, which featured a Pied Raven. It was designed by the famous Faroese artist and scientific illustrator Astrid Andreasen
.
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the Common Raven
Common Raven
The Common Raven , also known as the Northern Raven, is a large, all-black passerine bird. Found across the northern hemisphere, it is the most widely distributed of all corvids...
which was only found on the Faroe Islands
Faroe Islands
The Faroe Islands are an island group situated between the Norwegian Sea and the North Atlantic Ocean, approximately halfway between Scotland and Iceland. The Faroe Islands are a self-governing territory within the Kingdom of Denmark, along with Denmark proper and Greenland...
and has disappeared
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
since the mid twentieth century. It had large areas of white feathering, most frequently on the head, the wings and the belly, and its beak was light brown. Apart from that, it looked like the black birds (morpha typicus).
Description
Faroese language
Faroese , is an Insular Nordic language spoken by 48,000 people in the Faroe Islands and about 25,000 Faroese people in Denmark and elsewhere...
, the bird was called hvítravnur ("White Raven"), older name gorpur bringu hvíti ("White-chested Corbie"). Normal individuals of the subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
varius, which is found on Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...
and the Faroe Islands, already show a tendency towards more extensive white feather
Feather
Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...
bases compared with the nominate subspecies. But only on the Faroes, a mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
in the melanin
Melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...
metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
would become fixed in the population, causing some birds to have about half of their feathers entirely white. While albinotic specimens sometimes occur in bird populations, the Pied Raven seems not to have been based on such occasional "sports", but on a constantly or at least regularly present part of the local raven population.
As these birds freely interacted and interbred with the black ones which are still found on the islands, they did not constitute a distinct subspecies. However, they illustrate two aspects of population genetics: genetic drift
Genetic drift
Genetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
, which in small populations will shift allele
Allele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...
frequencies over time (in this case, causing the occasionally occurring mutation to spread and become a permanent part of the gene pool
Gene pool
In population genetics, a gene pool is the complete set of unique alleles in a species or population.- Description :A large gene pool indicates extensive genetic diversity, which is associated with robust populations that can survive bouts of intense selection...
of ravens on the Faroes), and how a new, distinct subspecies may 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...
over time from a distinct part of the population. Had the black and pied ravens mated preferentially
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 their own morph, in time the pied part of the population might have prevailed, as its coloration probably would have provided better camouflage
Camouflage
Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...
when preying on seabirds (most of which are also black-and-white).
Faroese literature
In the Middle Ages many poems and stories were handed down orally. These works were split into the following divisions: sagnir , ævintyr and kvæði . These were eventually written down in the 19th century.In the 13th century the Færeyinga saga was written in Iceland...
Fuglakvæði eldra ("The elder ballad of birds") which mentions 40 local species, including the Great Auk
Great Auk
The Great Auk, Pinguinus impennis, formerly of the genus Alca, was a large, flightless alcid that became extinct in the mid-19th century. It was the only modern species in the genus Pinguinus, a group of birds that formerly included one other species of flightless giant auk from the Atlantic Ocean...
. Later, the Pied Raven is mentioned in the reports of Lucas Debes
Lucas Debes
Lucas Jacobsøn Debes was a Danish priest, topographer and celebrated writer about the Faroe Islands. He wrote the first book about the Faroes, which was printed and draw the first detailed map of the islands.-His Arrival to Tórshavn:Debes came to the Faroe Islands in 1652 as a curate...
(1673) and Jens Christian Svabo
Jens Christian Svabo
Jens Christian Svabo was a pioneering Faroese linguist, scholar, and ethnographer. Svabo was born in Miðvágur, Vágar, the Faroe Islands to a minister and his wife. Svabo studied history, music, and theology in Miðvágur and later in Tórshavn. Between 1765 and 1800 he lived in Denmark and studied...
(1781/82). Carl Julian von Graba in 1828 speaks of ten individuals he saw himself and states that these birds, while less numerous than the black morph, were quite common.
Díðrikur á Skarvanesi
Díðrikur á Skarvanesi
Díðrikur á Skarvanesi also called Díðrikur í Kárastovu , was born in Dímun and was the first known painter in the Faroe Islands that art historians know of....
, the first Faroe painter, painted the Fuglar series, a number of portrayal of birds. On his 18 fuglar ("18 birds"), the animal in the lower right corner can be identified as a Pied Raven. The painting is currently on display in the Listaskálin museum of Faroe art in Tórshavn
Tórshavn
Tórshavn is the capital and largest town of the Faroe Islands. It is located in the southern part on the east coast of Streymoy. To the north west of the town lies the high mountain Húsareyn, and to the southwest, the high Kirkjubøreyn...
.
Disappearance
Streymoy
Streymoy is the largest and most populated island of the Faroe Islands. The capital, Tórshavn is located there. The name means "island of currents".- Geography :...
, Hans Christopher Müller once paid two Danish rigsdaler
Danish rigsdaler
The rigsdaler was the name of several currencies used in Denmark until 1873. The similarly named Reichsthaler, riksdaler and rijksdaalder were used in Germany and Austria-Hungary, Sweden and the Netherlands, respectively....
for a stuffed specimen from Nólsoy
Nólsoy
Nólsoy is an island and village in central Faroe Islands, located to the east of the capital Tórshavn in Streymoy. There is only one settlement on the island: Nólsoy on the north-west coast on Stongin, a peninsula attached to the rest of the island by a metres-wide isthmus...
. Such sums, a healthy amount of money for the impoverished Faroe farmers, made shooting a Pied Raven a profitable enterprise. Additionally, ravens in general were hunted as pests. In the mid nineteenth century, every Faroe male of hunting age was ordered by royal decree to shoot at least one raven or two other predatory birds per year or be fined four skilling
Swedish skilling
The skilling was the Scandinavian equivalent of the schilling or shilling. It was used as a subdivision of the Swedish riksdaler, the Danish rigsdaler, the Norwegian rigsdaler, and the Norwegian speciedaler.-Denmark:...
s. One of the last Pied Raven specimens was shot on November 2, 1902 on Mykines
Mykines
Mykines is the western-most of the main 18 islands in the Faroe Islands. See also the only settlement on the island, Mykines.Only 11 people live in village Mykines all year around. The oldest inhabitant is 75 and the youngest is 6 years old....
. In the autumn of 1916, another bird was seen at Velbastaður
Velbastaður
Velbastaður is a village on the island of Streymoy in the Faroe Islands.*Population: 164*Postal code : FO 176*Location: *Municipality: Torshavnar...
and on Koltur
Koltur
Koltur is an island in the Faroe Islands, located to the west of Streymoy and to the north of Hestur. The island has just one settlement: Koltur. It was abandoned in the 1980s by the sheep-farmers whose flocks grazed on the southern part of the island. Since then only two people have returned , and...
. The last known individual was found in the winter of 1947 on Nólsoy, and disappeared late in 1948. As these last sightings raised widespread interest, it seems probable that after 1948, no Pied Raven has been seen.
Recessive
In genetics, the term "recessive gene" refers to an allele that causes a phenotype that is only seen in a homozygous genotype and never in a heterozygous genotype. Every person has two copies of every gene on autosomal chromosomes, one from mother and one from father...
or (if more than one) only caused the novel coloration if they were all present. This is evidenced by the last sightings which occurred in the absence of a regular breeding population of piebald birds, and the observations of H. C. Müller. Thus, it is not certain that the form is indeed extinct, if one can speak of "extinction" in any but a population genetical
Population genetics
Population genetics is the study of allele frequency distribution and change under the influence of the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow. It also takes into account the factors of recombination, population subdivision and population...
sense anyway. Theoretically, the allele(s) could still be present but hidden in black individuals of the subspecies and thus, a Pied Raven could once again be born one day. As the raven population on the Faroes has declined to a few hundred birds at best over the recent decades, this does not seem very likely.
Today, 15 museum specimens of the Pied Raven are known: Six in Copenhagen
Copenhagen
Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...
(Zoologisk Museum), four in New York
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
, two in Uppsala
Uppsala
- Economy :Today Uppsala is well established in medical research and recognized for its leading position in biotechnology.*Abbott Medical Optics *GE Healthcare*Pfizer *Phadia, an offshoot of Pharmacia*Fresenius*Q-Med...
, one in Leiden, one in Braunschweig
Braunschweig
Braunschweig , is a city of 247,400 people, located in the federal-state of Lower Saxony, Germany. It is located north of the Harz mountains at the farthest navigable point of the Oker river, which connects to the North Sea via the rivers Aller and Weser....
(Naturhistorisches Museum) and one in Dresden
Dresden
Dresden is the capital city of the Free State of Saxony in Germany. It is situated in a valley on the River Elbe, near the Czech border. The Dresden conurbation is part of the Saxon Triangle metropolitan area....
. On June 12, 1995, the Postverk Føroya
Postverk Føroya
Posta is the postal service of the Faroe Islands and was founded on 1 April 1976 under the Home Rule of the Faroe Islands. On 16 December 2005, it became a public joint stock company under the name P/F Postverk Føroya ....
issued the postal stamp FR 276, which featured a Pied Raven. It was designed by the famous Faroese artist and scientific illustrator Astrid Andreasen
Astrid Andreasen
Astrid Jóhanna Andreasen is a Faroese textile and graphical artist, marine researcher and postage stamp designer. As a scientific illustrator, she specialises in marine animals....
.