Post by Eaglehawk on Dec 13, 2019 6:55:44 GMT
Carolina Parakeet - Conuropsis carolinensis
Extinct: 1918
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Psittaciformes
Superfamily: Psittacoidea
Family: Psittacidae
Subfamily: Arinae
Tribe: Arini
Genus: † Conuropsis
Species: † C. carolinensis
The Carolina parakeet (Conuropsis carolinensis) or Carolina conure was a small green Neotropical parrot with a bright yellow head, reddish orange face and pale beak native to the eastern, midwest and plains states of the United States and was the only indigenous parrot within its range. It was found from southern New York and Wisconsin to Kentucky, Tennessee and the Gulf of Mexico, from the Atlantic seaboard to as far west as eastern Colorado. It lived in old-growth forests along rivers and in swamps. It was called puzzi la née ("head of yellow") or pot pot chee by the Seminole and kelinky in Chickasaw. Though formerly prevalent within its range, the bird had become rare by the middle of the 19th century. The last confirmed sighting in the wild was of the ludovicianus subspecies in 1910. The last known specimen perished in captivity at Cincinnati Zoo in 1918 and the species was declared extinct in 1939.
The earliest reference to these parrots was in 1583 in Florida reported by Sir George Peckham in A True Report of the Late Discoveries of the Newfound Lands of expeditions conducted by English explorer Sir Humphrey Gilbert who notes that explorers in North America "doe testifie that they have found in those countryes; ... parrots." They were first scientifically described in English naturalist Mark Catesby's two volume Natural History of Carolina, Florida and the Bahama Islands published in London in 1731 and 1743.
Carolina parakeets were probably toxic—American naturalist and painter John J. Audubon noted that cats apparently died from eating them, and they are known to have eaten the toxic seeds of cockleburs.
Taxonomy
Carolinensis is a species of the genus Conuropsis, one of numerous genera of New World long-tailed parrots in tribe Arini, which also includes the Central and South American macaws. Tribe Arini together with the Amazonian parrots and a few miscellaneous genera make up subfamily Arinae of Neotropical parrots in family Psittacidae of true parrots. The specific name Psittacus carolinensis was assigned by Swedish zoologist Carolus Linnaeus in the 10th edition of Systema Naturae published in 1758. The species was given its own genus Conuropsis by Italian zoologist and ornithologist Tommaso Salvadori in 1891 in his Catalogue of the Birds in the British Museum, volume 20. The name is derived from the Greek-ified conure ("parrot of the genus Conurus" an obsolete name of genus Aratinga) + -opsis ("likeness of") and Latinized Carolina (from Carolana, an English colonial province".
There are two recognized subspecies. The Louisiana subspecies of the Carolina parakeet, C. c. ludovicianus, was slightly different in color than the nominate subspecies, being more bluish-green and generally of a somewhat subdued coloration, and went extinct in much the same way, but at a somewhat earlier date (early 1910s). The Appalachian Mountains separated these birds from the eastern C. c. carolinensis.
According to a study of mitochondrial DNA recovered from museum specimens, their closest living relatives include some of the South American Aratinga parakeets: the Nanday parakeet, the sun parakeet, and the golden-capped parakeet. The authors note the bright yellow and orange plumage and blue wing feathers found in Conuropsis carolinensis are traits shared by another species, the jenday parakeet (A. jandaya), that was not sampled in the study but is generally thought to be closely related. Carolinensis is in a sister clade to that of Spix's macaw. The Carolina parakeet colonized North America about 5.5 million years ago. This was well before North America and South America were joined together by the formation of the Panama land bridge about 3.5 mya. Since the Carolina parakeets' more distant relations are geographically closer to its own historic range whilst its closest relatives are more geographically distant to it, these data are consistent with the generally accepted hypothesis that Central and North America were colonized at different times by distinct lineages of parrots – parrots that originally invaded South America from Antarctica some time after the breakup of Gondwana, where Neotropical parrots originated approximately 50 mya.
A fossil parrot, designated Conuropsis fratercula, was described based on a single humerus from the Miocene Sheep Creek Formation (possibly late Hemingfordian, c. 16 mya, possibly later) of Snake River, Nebraska. This was a smaller bird, three-quarters the size of the Carolina parakeet. "The present species is of peculiar interest as it represents the first known parrotlike bird to be described as a fossil from North America." (Wetmore 1926). However, it is not altogether certain that this species is correctly assigned to Conuropsis, but some authors, consider it a paleosubspecies of the Carolina parakeet.
Description
The Carolina parakeet was a small green parrot very similar in size and coloration to the extant jenday and sun conures. The majority of the plumage was green with lighter green underparts, a bright yellow head and orange forehead and face extending to behind the eyes and upper cheeks (lores). The shoulders were yellow, continuing down the outer edge of the wings. The primary feathers were mostly green, but with yellow edges on the outer primaries. Thighs were green towards the top and yellow towards the feet. Male and female adults were identical in plumage, however males were slightly larger than females (sexually dimorphic). The legs and feet were light brown. They share the zygodactyl feet of the parrot family. The skin around the eyes was white and the beak was pale flesh colored. These birds weighed about 3.5 oz. were 13 in. long, and had wingspans of 21-23 in.
Young Carolina parakeets differed slightly in coloration from adults. The face and entire body was green, with paler underparts. They lacked yellow or orange plumage on the face, wings, and thighs. Hatchlings were covered in mouse-gray down, until about 39–40 days when green wings and tails appear. Fledglings had full adult plumage at around 1 year of age. These birds were fairly long lived, at least in captivity - a pair was kept at the Cincinnati Zoo for over 35 years.
Range and Habitat
The Carolina parakeet had the northern-most range of any known parrot. It was found from southern New England and New York and Wisconsin to Kentucky, Tennessee and the Gulf of Mexico. Its also had a wide distribution west of the Mississippi River, as far west as eastern Colorado. Its range was described by early explorers thus: the 43rd parallel as the northern limit, the 26th as the most southern, the 73rd and 106th meridians as the eastern and western boundaries respectively, the range included all or portions of at least 28 states. Its habitats were old-growth wetland forests along rivers and in swamps especially in the Mississippi-Missouri drainage basin with large hollow trees including cypress and sycamore to use as roosting and nesting sites.
Only very rough estimates of the birds' former prevalence can be made: with an estimated range of 20,000 to 2.5 million km2, and population density of 0.5 to 2.0 parrots per km2, population estimates range from tens of thousands to a few million birds (though the densest populations occurred in Florida covering 170,000 km2, so there may have been hundreds of thousands of the birds in that state alone).
The species may have appeared as a very rare vagrant in places as far north as Southern Ontario. A few bones, including a pygostyle found at the Calvert Site in Southern Ontario, came from the Carolina parakeet. The possibility remains open that this specimen was taken to Southern Ontario for ceremonial purposes.
Behavior and Diet
The bird lived in huge, noisy flocks of as many as 200-300 birds. They built their nests in hollow trees, laying two to five (most accounts say two) 1.6 in round white eggs. It mostly ate the seeds of forest trees and shrubs including those of cypress, hackberry, beech, sycamore, elm, pine, maple, oak, and other plants such as thistles and sandspurs (Cenchrus species). It also ate fruits including apples, grapes and figs (often from orchards by the time of its decline). They were especially noted for their predilection for cockleburs (Xanthium strumarium), a plant which contains a toxic glucoside, and was an invasive pest in southern farms and fields.
Extinction
There are no scientific studies or surveys of this bird by American naturalists; most information about it is from anecdotal accounts and museum specimens. Therefore details of its prevalence and decline are unverified or speculative. There are extensive accounts of the pre-colonial and early colonial prevalence of this bird. The existence of flocks of gregarious, very colorful and raucous parrots could hardly have gone unnoted by European explorers, as parrots were virtually unknown in seafaring European nations in the 16th and 17th centuries. Later accounts in the latter half of the 19th century onward noted the birds' sparseness and absence.
The birds' range collapsed from east to west with settlement and clearing of the eastern and southern deciduous forests. John J. Audubon commented as early as 1832 on the decline of the birds. The bird was rarely reported outside Florida after 1860. The last reported sighting east of the Mississippi River (except Florida) was in 1878 in Kentucky. By the turn-of-the-century it was restricted to the swamps of central Florida. The last known wild specimen was killed in Okeechobee County, Florida, in 1904, and the last captive bird died at the Cincinnati Zoo on February 21, 1918. This was the male specimen, called "Incas", who died within a year of his mate, "Lady Jane". Additional reports of the bird were made in Okeechobee County, Florida, until the late 1920s, but these are not supported by specimens. It was not until 1939, however, that the American Ornithologists' Union declared that the Carolina parakeet had become extinct. The IUCN has listed the species as extinct since 1918.
n 1937, three parakeets resembling this species were sighted and filmed in the Okefenokee Swamp of Georgia. However, the American Ornithologists' Union analyzed the film and concluded that they had probably filmed feral parakeets. About 720 skins and 16 skeletons are housed in museums around the world and analyzable DNA has been extracted from them.
The evidence is rather conclusive that extinction of the Carolina parakeet was by anthropogenic activity, through a variety of means. Chief among them is deforestation in the 18th and 19th centuries. Hunting played a significant role, both for their colorful feathers used to adorn women's hats and to reduce predation on southern crops. This was partially offset by recognition of their value in controlling invasive cockleburs. Minor roles were played by capture for the pet trade and, it was hypothesized, by the introduction for crop pollination of European honeybees that competed for nest sites.
A factor that exacerbated their decline to extinction was the unfortunate flocking behavior that led them to return to the vicinity of dead and dying birds (e.g., birds downed by hunting), enabling wholesale slaughter. The final extinction of the species in the early years of the 20th century is somewhat of a mystery, as it happened so rapidly. Vigorous flocks with many juveniles and reproducing pairs were noted as late as 1896, and the birds were long-lived in captivity, but they had virtually disappeared by 1904. Sufficient nest sites remained intact, so deforestation was not the final cause. American ornithologist Noel F. Snyder speculates that the most likely cause seems to be that the birds succumbed to poultry disease, this in spite of the fact that no recent or historical records exist of New World parrot populations being afflicted by domestic poultry diseases. The modern poultry scourge Newcastle disease was not detected until 1926 in Indonesia, and only a subacute form of it was reported in the United States in 1938.
Carolina parakeet extinction was driven by human causes, DNA sequencing reveals
by Universitat Pompeu Fabra - Barcelona
The image of the Carolina parakeet (Conuropsis carolinensis) specimen. Credit: Marc Durà
Researchers from the Institute of Evolutionary Biology (IBE, a joint institute of the Pompeu Fabra University (UPF) and the Spanish National Research Council (CSIC)) in Barcelona and the Globe Institute at the University of Copenhagen have unveiled the genome of the Carolina parakeet, declared extinct at the beginning of the 20th century. Researchers explored the genome for signs found in endangered species but did not find them, suggesting that Carolina parakeet extinction was an abrupt process and thus solely attributable to human causes.
The Carolina parakeet (Conuropsis carolinensis) is an iconic North American bird declared extinct at the beginning of the 20th century after the death of the last specimen at the Cincinnati zoo in 1918. It was the member of the parrot family to live in the highest northern latitude of the planet, and was distributed from southern New England to the Gulf of Mexico, and all the way to eastern Colorado. It had a striking colour pattern: green in the body, yellow on its head and orange on its face.
Despite flying in noisy flocks of hundreds of individuals, it was extensively hunted during the last decades of the 19th century, in part for obtaining its feathers to decorate hats. Still, the cause of its extinction remains contentious. Although its excessive mortality could well be associated with its recent habitat destruction and active hunting, its survival could also been negatively affected by its range having become increasingly patchy or by the exposure to poultry pathogens.
Now, an international team of researchers, led by IBE Research Professor Carles Lalueza-Fox and Globe Institute Professor M. Thomas P. Gilbert has reconstructed the first complete genome of the extinct Carolina parakeet unveiling the evolutionary history and possible cause of extinction of this paradigmatic bird.
Researchers sampled the tibia bone and the toe pads of a naturalized specimen preserved in a private collection at Espinelves (Girona, Spain) that was collected by Catalan naturalist Marià Masferrer (1856-1923). In order to map the complete genome of the extinct bird, they had to sequence first the genome of a close living relative, the Aratinga solstitialis or sun parakeet from South America.
The genomic analysis of both genomes along with hundreds of other avian genomes determined that the Carolina parakeet and the sun parakeet diverged around 3 million years ago, coinciding with the closing of the Isthmus of Panama.
The Carolina parakeet showed a predilection for eating cockleburs, a plant that contains a powerful toxic that didn't affect the bird but made them notoriously toxic for predators. The genomic analysis unveiled a potential adaptation to this cocklebur diet in two extremely conserved proteins that are known to interact with this toxic.
Researchers also explored the genome for signs of inbreeding and population decline that are sometimes found in endangered species but did not find them, which suggests that its rapid extinction was mainly a human-mediated process. Now, experts wonder if de-extinguishing the Carolina parakeet would be possible. "Despite the Carolina parakeet appears in all de-extinction lists, we found hundreds of genetic changes predicted to be deleterious with the closest living relative, the sun parakeet, which indicates the enormous difficulties of undertaking such enterprises," says Lalueza-Fox.
The methodology developed to reconstruct the extinction history from the bird genome could be used in the future to foresee other possible human-related extinctions, and to further protect the endangered species by applying conservation plans in time. "We can use genomics to test the dynamics of other extinction processes and infer if they are entirely caused by humans, because long-term demographic declines leave specific signals in the genomes of the species," concludes Lalueza-Fox.
Interestingly, this project started in a catalan popular science programme, "Quèquicom," directed by UPF professor Jaume Vilalta. Pere Renom, Ph.D. student at the IBE and reporter of the TV3 programme back then, discovered that one Carolina parakeet specimen, which was collected by a Catalan naturalist at the beginning of the 20th century in the U.S., was preserved at a private collection in Espinelves (Girona, Spain). Renom contacted Lalueza-Fox to film the whole process of the genome reconstruction from the stuffed specimen to talk about de-extinction for the TV3 show. "Renom contacted me asking if I would be interested in trying to retrieve DNA from the specimen, and the story ended up two years later with the first complete genome of this North American bird done at the IBE," Lalueza-Fox explains.
The complete story of the discovery can be seen at the "Quèquicom" episode called "Desextinció: reviure una espècie," recently awarded with the Spanish Prismas prize as the best video of scientific dissemination of 2019.
Journal Reference:
Pere Gelabert, et. al. Evolutionary History, Genomic Adaptation to Toxic Diet, and Extinction of the Carolina Parakeet, Current Biology; December 2019. DOI: doi.org/10.1016/j.cub.2019.10.066
Summary
As the only endemic neotropical parrot to have recently lived in the northern hemisphere, the Carolina parakeet (Conuropsis carolinensis) was an iconic North American bird. The last surviving specimen died in the Cincinnati Zoo in 1918. The cause of its extinction remains contentious: besides excessive mortality associated to habitat destruction and active hunting, their survival could have been negatively affected by its range having become increasingly patchy or by the exposure to poultry pathogens. In addition, the Carolina parakeet showed a predilection for cockleburs, an herbaceous plant that contains a powerful toxin, carboxyatractyloside, or CAT, which did not seem to affect them but made the birds notoriously toxic to most predators. To explore the demographic history of this bird, we generated the complete genomic sequence of a preserved specimen held in a private collection in Espinelves (Girona, Spain), as well as of a close extant relative, Aratinga solstitialis. We identified two non-synonymous genetic changes in two highly conserved proteins known to interact with CAT that could underlie a specific dietary adaptation to this toxin. Our genomic analyses did not reveal evidence of a dramatic past demographic decline in the Carolina parakeet; also, its genome did not exhibit the long runs of homozygosity that are signals of recent inbreeding and are typically found in endangered species. As such, our results suggest its extinction was an abrupt process and thus likely solely attributable to human causes.
www.cell.com/current-biology/fulltext/S0960-9822(19)31438-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982219314381%3Fshowall%3Dtrue
Extinct: 1918
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Psittaciformes
Superfamily: Psittacoidea
Family: Psittacidae
Subfamily: Arinae
Tribe: Arini
Genus: † Conuropsis
Species: † C. carolinensis
The Carolina parakeet (Conuropsis carolinensis) or Carolina conure was a small green Neotropical parrot with a bright yellow head, reddish orange face and pale beak native to the eastern, midwest and plains states of the United States and was the only indigenous parrot within its range. It was found from southern New York and Wisconsin to Kentucky, Tennessee and the Gulf of Mexico, from the Atlantic seaboard to as far west as eastern Colorado. It lived in old-growth forests along rivers and in swamps. It was called puzzi la née ("head of yellow") or pot pot chee by the Seminole and kelinky in Chickasaw. Though formerly prevalent within its range, the bird had become rare by the middle of the 19th century. The last confirmed sighting in the wild was of the ludovicianus subspecies in 1910. The last known specimen perished in captivity at Cincinnati Zoo in 1918 and the species was declared extinct in 1939.
The earliest reference to these parrots was in 1583 in Florida reported by Sir George Peckham in A True Report of the Late Discoveries of the Newfound Lands of expeditions conducted by English explorer Sir Humphrey Gilbert who notes that explorers in North America "doe testifie that they have found in those countryes; ... parrots." They were first scientifically described in English naturalist Mark Catesby's two volume Natural History of Carolina, Florida and the Bahama Islands published in London in 1731 and 1743.
Carolina parakeets were probably toxic—American naturalist and painter John J. Audubon noted that cats apparently died from eating them, and they are known to have eaten the toxic seeds of cockleburs.
Taxonomy
Carolinensis is a species of the genus Conuropsis, one of numerous genera of New World long-tailed parrots in tribe Arini, which also includes the Central and South American macaws. Tribe Arini together with the Amazonian parrots and a few miscellaneous genera make up subfamily Arinae of Neotropical parrots in family Psittacidae of true parrots. The specific name Psittacus carolinensis was assigned by Swedish zoologist Carolus Linnaeus in the 10th edition of Systema Naturae published in 1758. The species was given its own genus Conuropsis by Italian zoologist and ornithologist Tommaso Salvadori in 1891 in his Catalogue of the Birds in the British Museum, volume 20. The name is derived from the Greek-ified conure ("parrot of the genus Conurus" an obsolete name of genus Aratinga) + -opsis ("likeness of") and Latinized Carolina (from Carolana, an English colonial province".
There are two recognized subspecies. The Louisiana subspecies of the Carolina parakeet, C. c. ludovicianus, was slightly different in color than the nominate subspecies, being more bluish-green and generally of a somewhat subdued coloration, and went extinct in much the same way, but at a somewhat earlier date (early 1910s). The Appalachian Mountains separated these birds from the eastern C. c. carolinensis.
According to a study of mitochondrial DNA recovered from museum specimens, their closest living relatives include some of the South American Aratinga parakeets: the Nanday parakeet, the sun parakeet, and the golden-capped parakeet. The authors note the bright yellow and orange plumage and blue wing feathers found in Conuropsis carolinensis are traits shared by another species, the jenday parakeet (A. jandaya), that was not sampled in the study but is generally thought to be closely related. Carolinensis is in a sister clade to that of Spix's macaw. The Carolina parakeet colonized North America about 5.5 million years ago. This was well before North America and South America were joined together by the formation of the Panama land bridge about 3.5 mya. Since the Carolina parakeets' more distant relations are geographically closer to its own historic range whilst its closest relatives are more geographically distant to it, these data are consistent with the generally accepted hypothesis that Central and North America were colonized at different times by distinct lineages of parrots – parrots that originally invaded South America from Antarctica some time after the breakup of Gondwana, where Neotropical parrots originated approximately 50 mya.
A fossil parrot, designated Conuropsis fratercula, was described based on a single humerus from the Miocene Sheep Creek Formation (possibly late Hemingfordian, c. 16 mya, possibly later) of Snake River, Nebraska. This was a smaller bird, three-quarters the size of the Carolina parakeet. "The present species is of peculiar interest as it represents the first known parrotlike bird to be described as a fossil from North America." (Wetmore 1926). However, it is not altogether certain that this species is correctly assigned to Conuropsis, but some authors, consider it a paleosubspecies of the Carolina parakeet.
Description
The Carolina parakeet was a small green parrot very similar in size and coloration to the extant jenday and sun conures. The majority of the plumage was green with lighter green underparts, a bright yellow head and orange forehead and face extending to behind the eyes and upper cheeks (lores). The shoulders were yellow, continuing down the outer edge of the wings. The primary feathers were mostly green, but with yellow edges on the outer primaries. Thighs were green towards the top and yellow towards the feet. Male and female adults were identical in plumage, however males were slightly larger than females (sexually dimorphic). The legs and feet were light brown. They share the zygodactyl feet of the parrot family. The skin around the eyes was white and the beak was pale flesh colored. These birds weighed about 3.5 oz. were 13 in. long, and had wingspans of 21-23 in.
Young Carolina parakeets differed slightly in coloration from adults. The face and entire body was green, with paler underparts. They lacked yellow or orange plumage on the face, wings, and thighs. Hatchlings were covered in mouse-gray down, until about 39–40 days when green wings and tails appear. Fledglings had full adult plumage at around 1 year of age. These birds were fairly long lived, at least in captivity - a pair was kept at the Cincinnati Zoo for over 35 years.
Range and Habitat
The Carolina parakeet had the northern-most range of any known parrot. It was found from southern New England and New York and Wisconsin to Kentucky, Tennessee and the Gulf of Mexico. Its also had a wide distribution west of the Mississippi River, as far west as eastern Colorado. Its range was described by early explorers thus: the 43rd parallel as the northern limit, the 26th as the most southern, the 73rd and 106th meridians as the eastern and western boundaries respectively, the range included all or portions of at least 28 states. Its habitats were old-growth wetland forests along rivers and in swamps especially in the Mississippi-Missouri drainage basin with large hollow trees including cypress and sycamore to use as roosting and nesting sites.
Only very rough estimates of the birds' former prevalence can be made: with an estimated range of 20,000 to 2.5 million km2, and population density of 0.5 to 2.0 parrots per km2, population estimates range from tens of thousands to a few million birds (though the densest populations occurred in Florida covering 170,000 km2, so there may have been hundreds of thousands of the birds in that state alone).
The species may have appeared as a very rare vagrant in places as far north as Southern Ontario. A few bones, including a pygostyle found at the Calvert Site in Southern Ontario, came from the Carolina parakeet. The possibility remains open that this specimen was taken to Southern Ontario for ceremonial purposes.
Behavior and Diet
The bird lived in huge, noisy flocks of as many as 200-300 birds. They built their nests in hollow trees, laying two to five (most accounts say two) 1.6 in round white eggs. It mostly ate the seeds of forest trees and shrubs including those of cypress, hackberry, beech, sycamore, elm, pine, maple, oak, and other plants such as thistles and sandspurs (Cenchrus species). It also ate fruits including apples, grapes and figs (often from orchards by the time of its decline). They were especially noted for their predilection for cockleburs (Xanthium strumarium), a plant which contains a toxic glucoside, and was an invasive pest in southern farms and fields.
Extinction
There are no scientific studies or surveys of this bird by American naturalists; most information about it is from anecdotal accounts and museum specimens. Therefore details of its prevalence and decline are unverified or speculative. There are extensive accounts of the pre-colonial and early colonial prevalence of this bird. The existence of flocks of gregarious, very colorful and raucous parrots could hardly have gone unnoted by European explorers, as parrots were virtually unknown in seafaring European nations in the 16th and 17th centuries. Later accounts in the latter half of the 19th century onward noted the birds' sparseness and absence.
The birds' range collapsed from east to west with settlement and clearing of the eastern and southern deciduous forests. John J. Audubon commented as early as 1832 on the decline of the birds. The bird was rarely reported outside Florida after 1860. The last reported sighting east of the Mississippi River (except Florida) was in 1878 in Kentucky. By the turn-of-the-century it was restricted to the swamps of central Florida. The last known wild specimen was killed in Okeechobee County, Florida, in 1904, and the last captive bird died at the Cincinnati Zoo on February 21, 1918. This was the male specimen, called "Incas", who died within a year of his mate, "Lady Jane". Additional reports of the bird were made in Okeechobee County, Florida, until the late 1920s, but these are not supported by specimens. It was not until 1939, however, that the American Ornithologists' Union declared that the Carolina parakeet had become extinct. The IUCN has listed the species as extinct since 1918.
n 1937, three parakeets resembling this species were sighted and filmed in the Okefenokee Swamp of Georgia. However, the American Ornithologists' Union analyzed the film and concluded that they had probably filmed feral parakeets. About 720 skins and 16 skeletons are housed in museums around the world and analyzable DNA has been extracted from them.
The evidence is rather conclusive that extinction of the Carolina parakeet was by anthropogenic activity, through a variety of means. Chief among them is deforestation in the 18th and 19th centuries. Hunting played a significant role, both for their colorful feathers used to adorn women's hats and to reduce predation on southern crops. This was partially offset by recognition of their value in controlling invasive cockleburs. Minor roles were played by capture for the pet trade and, it was hypothesized, by the introduction for crop pollination of European honeybees that competed for nest sites.
A factor that exacerbated their decline to extinction was the unfortunate flocking behavior that led them to return to the vicinity of dead and dying birds (e.g., birds downed by hunting), enabling wholesale slaughter. The final extinction of the species in the early years of the 20th century is somewhat of a mystery, as it happened so rapidly. Vigorous flocks with many juveniles and reproducing pairs were noted as late as 1896, and the birds were long-lived in captivity, but they had virtually disappeared by 1904. Sufficient nest sites remained intact, so deforestation was not the final cause. American ornithologist Noel F. Snyder speculates that the most likely cause seems to be that the birds succumbed to poultry disease, this in spite of the fact that no recent or historical records exist of New World parrot populations being afflicted by domestic poultry diseases. The modern poultry scourge Newcastle disease was not detected until 1926 in Indonesia, and only a subacute form of it was reported in the United States in 1938.
Carolina parakeet extinction was driven by human causes, DNA sequencing reveals
by Universitat Pompeu Fabra - Barcelona
The image of the Carolina parakeet (Conuropsis carolinensis) specimen. Credit: Marc Durà
Researchers from the Institute of Evolutionary Biology (IBE, a joint institute of the Pompeu Fabra University (UPF) and the Spanish National Research Council (CSIC)) in Barcelona and the Globe Institute at the University of Copenhagen have unveiled the genome of the Carolina parakeet, declared extinct at the beginning of the 20th century. Researchers explored the genome for signs found in endangered species but did not find them, suggesting that Carolina parakeet extinction was an abrupt process and thus solely attributable to human causes.
The Carolina parakeet (Conuropsis carolinensis) is an iconic North American bird declared extinct at the beginning of the 20th century after the death of the last specimen at the Cincinnati zoo in 1918. It was the member of the parrot family to live in the highest northern latitude of the planet, and was distributed from southern New England to the Gulf of Mexico, and all the way to eastern Colorado. It had a striking colour pattern: green in the body, yellow on its head and orange on its face.
Despite flying in noisy flocks of hundreds of individuals, it was extensively hunted during the last decades of the 19th century, in part for obtaining its feathers to decorate hats. Still, the cause of its extinction remains contentious. Although its excessive mortality could well be associated with its recent habitat destruction and active hunting, its survival could also been negatively affected by its range having become increasingly patchy or by the exposure to poultry pathogens.
Now, an international team of researchers, led by IBE Research Professor Carles Lalueza-Fox and Globe Institute Professor M. Thomas P. Gilbert has reconstructed the first complete genome of the extinct Carolina parakeet unveiling the evolutionary history and possible cause of extinction of this paradigmatic bird.
Researchers sampled the tibia bone and the toe pads of a naturalized specimen preserved in a private collection at Espinelves (Girona, Spain) that was collected by Catalan naturalist Marià Masferrer (1856-1923). In order to map the complete genome of the extinct bird, they had to sequence first the genome of a close living relative, the Aratinga solstitialis or sun parakeet from South America.
The genomic analysis of both genomes along with hundreds of other avian genomes determined that the Carolina parakeet and the sun parakeet diverged around 3 million years ago, coinciding with the closing of the Isthmus of Panama.
The Carolina parakeet showed a predilection for eating cockleburs, a plant that contains a powerful toxic that didn't affect the bird but made them notoriously toxic for predators. The genomic analysis unveiled a potential adaptation to this cocklebur diet in two extremely conserved proteins that are known to interact with this toxic.
Researchers also explored the genome for signs of inbreeding and population decline that are sometimes found in endangered species but did not find them, which suggests that its rapid extinction was mainly a human-mediated process. Now, experts wonder if de-extinguishing the Carolina parakeet would be possible. "Despite the Carolina parakeet appears in all de-extinction lists, we found hundreds of genetic changes predicted to be deleterious with the closest living relative, the sun parakeet, which indicates the enormous difficulties of undertaking such enterprises," says Lalueza-Fox.
The methodology developed to reconstruct the extinction history from the bird genome could be used in the future to foresee other possible human-related extinctions, and to further protect the endangered species by applying conservation plans in time. "We can use genomics to test the dynamics of other extinction processes and infer if they are entirely caused by humans, because long-term demographic declines leave specific signals in the genomes of the species," concludes Lalueza-Fox.
Interestingly, this project started in a catalan popular science programme, "Quèquicom," directed by UPF professor Jaume Vilalta. Pere Renom, Ph.D. student at the IBE and reporter of the TV3 programme back then, discovered that one Carolina parakeet specimen, which was collected by a Catalan naturalist at the beginning of the 20th century in the U.S., was preserved at a private collection in Espinelves (Girona, Spain). Renom contacted Lalueza-Fox to film the whole process of the genome reconstruction from the stuffed specimen to talk about de-extinction for the TV3 show. "Renom contacted me asking if I would be interested in trying to retrieve DNA from the specimen, and the story ended up two years later with the first complete genome of this North American bird done at the IBE," Lalueza-Fox explains.
The complete story of the discovery can be seen at the "Quèquicom" episode called "Desextinció: reviure una espècie," recently awarded with the Spanish Prismas prize as the best video of scientific dissemination of 2019.
Journal Reference:
Pere Gelabert, et. al. Evolutionary History, Genomic Adaptation to Toxic Diet, and Extinction of the Carolina Parakeet, Current Biology; December 2019. DOI: doi.org/10.1016/j.cub.2019.10.066
Summary
As the only endemic neotropical parrot to have recently lived in the northern hemisphere, the Carolina parakeet (Conuropsis carolinensis) was an iconic North American bird. The last surviving specimen died in the Cincinnati Zoo in 1918. The cause of its extinction remains contentious: besides excessive mortality associated to habitat destruction and active hunting, their survival could have been negatively affected by its range having become increasingly patchy or by the exposure to poultry pathogens. In addition, the Carolina parakeet showed a predilection for cockleburs, an herbaceous plant that contains a powerful toxin, carboxyatractyloside, or CAT, which did not seem to affect them but made the birds notoriously toxic to most predators. To explore the demographic history of this bird, we generated the complete genomic sequence of a preserved specimen held in a private collection in Espinelves (Girona, Spain), as well as of a close extant relative, Aratinga solstitialis. We identified two non-synonymous genetic changes in two highly conserved proteins known to interact with CAT that could underlie a specific dietary adaptation to this toxin. Our genomic analyses did not reveal evidence of a dramatic past demographic decline in the Carolina parakeet; also, its genome did not exhibit the long runs of homozygosity that are signals of recent inbreeding and are typically found in endangered species. As such, our results suggest its extinction was an abrupt process and thus likely solely attributable to human causes.
www.cell.com/current-biology/fulltext/S0960-9822(19)31438-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982219314381%3Fshowall%3Dtrue