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The passenger pigeon or wild pigeon (''Ectopistes migratorius'') is an extinct species of
Swedish naturalist
The passenger pigeon was a member of the pigeon and dove family,
pigeon
Columbidae is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with small heads, relatively short necks and slender bills that in some species feature fleshy ceres. ...
that was endemic
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
. Its common name is derived from the French word ''passager'', meaning "passing by", due to the migratory habits of the species. The scientific name also refers to its migratory characteristics. The morphologically similar mourning dove
The mourning dove (''Zenaida macroura'') is a member of the dove Family (biology), family, Columbidae. The bird is also known as the American mourning dove, the rain dove, the chueybird, colloquially as the turtle dove, and it was once known a ...
(''Zenaida macroura'') was long thought to be its closest relative, and the two were at times confused, but genetic analysis has shown that the genus '' Patagioenas'' is more closely related to it than the ''Zenaida'' doves.
The passenger pigeon was sexually dimorphic
Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
in size and coloration. The male was in length, mainly gray on the upperparts, lighter on the underparts, with iridescent
Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear gradually to change colour as the angle of view or the angle of illumination changes. Iridescence is caused by wave interference of light in microstruc ...
bronze feathers on the neck, and black spots on the wings. The female was , and was duller and browner than the male overall. The juvenile was similar to the female, but without iridescence. It mainly inhabited the deciduous forests
In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, after flo ...
of eastern North America and was also recorded elsewhere, but bred primarily around the Great Lakes
The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, H ...
. The pigeon migrated in enormous flocks, constantly searching for food, shelter, and breeding grounds, and was once the most abundant bird in North America, numbering around 3 billion, and possibly up to 5 billion. A very fast flyer, the passenger pigeon could reach a speed of . The bird fed mainly on mast, and also fruits and invertebrates. It practiced communal roosting and communal breeding, and its extreme gregariousness may have been linked with searching for food and predator satiation.
Passenger pigeons were hunted by Native Americans, but hunting intensified after the arrival of Europeans, particularly in the 19th century. Pigeon meat was commercialized as cheap food, resulting in hunting
Hunting is the Human activity, human practice of seeking, pursuing, capturing, and killing wildlife or feral animals. The most common reasons for humans to hunt are to obtain the animal's body for meat and useful animal products (fur/hide (sk ...
on a massive scale for many decades. There were several other factors contributing to the decline and subsequent extinction of the species, including shrinking of the large breeding populations necessary for preservation of the species and widespread deforestation
Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...
, which destroyed its habitat
In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...
. A slow decline between about 1800 and 1870 was followed by a rapid decline between 1870 and 1890. In 1900, the last confirmed wild bird was shot in southern Ohio. The last captive birds were divided in three groups around the turn of the 20th century, some of which were photographed alive. Martha
Martha (Aramaic language, Aramaic: מָרְתָא) is a Bible, biblical figure described in the Gospels of Gospel of Luke, Luke and Gospel of John, John. Together with her siblings Lazarus of Bethany, Lazarus and Mary of Bethany, she is descr ...
, thought to be the last passenger pigeon, died on September 1, 1914, at the Cincinnati Zoo. The eradication of the species is a notable example of anthropogenic extinction.
Taxonomy
Swedish naturalist Carl Linnaeus
Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...
coined the binomial name ''Columba
Columba () or Colmcille (7 December 521 – 9 June 597 AD) was an Irish abbot and missionary evangelist credited with spreading Christianity in what is today Scotland at the start of the Hiberno-Scottish mission. He founded the important abbey ...
macroura'' for both the mourning dove
The mourning dove (''Zenaida macroura'') is a member of the dove Family (biology), family, Columbidae. The bird is also known as the American mourning dove, the rain dove, the chueybird, colloquially as the turtle dove, and it was once known a ...
and the passenger pigeon in the 1758 edition of his work ''Systema Naturae
' (originally in Latin written ' with the Orthographic ligature, ligature æ) is one of the major works of the Sweden, Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the syste ...
'' (the starting point of biological nomenclature
Nomenclature codes or codes of nomenclature are the various rulebooks that govern the naming of living organisms. Standardizing the Binomial nomenclature, scientific names of biological organisms allows researchers to discuss findings (including ...
), wherein he appears to have considered the two identical. This composite description cited accounts of these birds in two pre-Linnean books. One of these was Mark Catesby
Mark Catesby (24 March 1683 – 23 December 1749) was an English natural history, naturalist who studied the flora and fauna of the New World. Between 1729 and 1747, Catesby published his ''Natural History of Carolina, Florida and the Bahama ...
's description of the passenger pigeon, which was published in his 1731 to 1743 work ''Natural History of Carolina, Florida and the Bahama Islands'', which referred to this bird as ''Palumbus migratorius'', and was accompanied by the earliest published illustration of the species. Catesby's description was combined with the 1743 description of the mourning dove by George Edwards, who used the name ''C. macroura'' for that bird. There is nothing to suggest Linnaeus ever saw specimens of these birds himself, and his description is thought to be fully derivative of these earlier accounts and their illustrations. In his 1766 edition of ''Systema Naturae'', Linnaeus dropped the name ''C. macroura'', and instead used the name ''C. migratoria'' for the passenger pigeon, and ''C. carolinensis'' for the mourning dove. In the same edition, Linnaeus also named ''C. canadensis'', based on ''Turtur canadensis'', as used by Mathurin Jacques Brisson
Mathurin Jacques Brisson (; 30 April 1723 – 23 June 1806) was a French zoologist and natural philosophy, natural philosopher.
Brisson was born on 30 April 1723 at Fontenay-le-Comte in the Vendée department of western France. Note that page 14 ...
in 1760. Brisson's description was later shown to have been based on a female passenger pigeon.
In 1827, William Swainson
William Swainson Fellow of the Linnean Society, FLS, Fellow of the Royal Society, FRS (8 October 1789 – 6 December 1855), was an English ornithologist, Malacology, malacologist, Conchology, conchologist, entomologist and artist.
Life
Swains ...
moved the passenger pigeon from the genus ''Columba'' to the new monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...
genus ''Ectopistes'', due in part to the length of the wings and the wedge shape of the tail. In 1906 Outram Bangs
Outram Bangs (January 12, 1863 – September 22, 1932) was an American zoologist.
Biography
Bangs was born in Watertown, Massachusetts, as the second son of Edward and Annie Outram (Hodgkinson) Bangs. He studied at Harvard from 1880 to 1884, a ...
suggested that because Linnaeus had wholly copied Catesby's text when coining ''C. macroura'', this name should apply to the passenger pigeon, as ''E. macroura''. In 1918 Harry C. Oberholser suggested that ''C. canadensis'' should take precedence over ''C. migratoria'' (as ''E. canadensis''), as it appeared on an earlier page in Linnaeus' book. In 1952 Francis Hemming proposed that the International Commission on Zoological Nomenclature
The International Commission on Zoological Nomenclature (ICZN) is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 26 commissioners from 20 countries.
Orga ...
(ICZN) secure the specific name ''macroura'' for the mourning dove, and the name ''migratorius'' for the passenger pigeon, since this was the intended use by the authors on whose work Linnaeus had based his description. This was accepted by the ICZN, which used its plenary powers to designate the species for the respective names in 1955.
Evolution
The passenger pigeon was a member of the pigeon and dove family, Columbidae
Columbidae is a bird Family (biology), family consisting of doves and pigeons. It is the only family in the Order (biology), order Columbiformes. These are stout-bodied birds with small heads, relatively short necks and slender bills that in ...
. The oldest known fossil of the genus is an isolated humerus (USNM 430960) known from the Lee Creek Mine in North Carolina in sediments belonging to the Yorktown Formation, dating to the Zanclean
The Zanclean is the lowest stage or earliest age on the geologic time scale of the Pliocene. It spans the time between 5.332 ± 0.005 Ma (million years ago) and 3.6 ± 0.005 Ma. It is preceded by the Messinian Age of the Miocene Epoch, and f ...
stage of the Pliocene
The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58''Zenaida'' doves, based on morphological grounds, particularly the physically similar mourning dove (now ''Z. macroura''). It was even suggested that the mourning dove belonged to the genus ''Ectopistes'' and was listed as ''E. carolinensis'' by some authors, including Thomas Mayo Brewer. The passenger pigeon was supposedly descended from ''Zenaida'' pigeons that had adapted to the woodlands on the plains of central North America.
The passenger pigeon differed from the species in the genus ''Zenaida'' in being larger, lacking a facial stripe, being
The passenger pigeon was physically adapted for speed, endurance, and maneuverability in flight, and has been described as having a streamlined version of the typical pigeon shape, such as that of the generalized
The noise produced by flocks of passenger pigeons was described as deafening, audible for miles away, and the bird's voice as loud, harsh, and unmusical. It was also described by some as clucks, twittering, and cooing, and as a series of low notes, instead of an actual song. The birds apparently made croaking noises when building nests, and bell-like sounds when mating. During feeding, some individuals would give
The passenger pigeon was found across most of North America east of the
The passenger pigeon was one of the most social of all land birds. Estimated to have numbered three to five billion at the height of its population, it may have been the most numerous bird on Earth; researcher Arlie W. Schorger believed that it accounted for between 25 and 40 percent of the total land bird population in the United States. The passenger pigeon's historic population is roughly the equivalent of the number of birds that overwinter in the United States every year in the early 21st century. Even within their range, the size of individual flocks could vary greatly. In November 1859, 
A communally roosting species, the passenger pigeon chose roosting sites that could provide shelter and enough food to sustain their large numbers for an indefinite period. The time spent at one roosting site may have depended on the extent of human persecution, weather conditions, or other, unknown factors. Roosts ranged in size and extent, from a few acres to or greater. Some roosting areas would be reused for subsequent years, others would only be used once. The passenger pigeon roosted in such numbers that even thick tree branches would break under the strain. The birds frequently piled on top of each other's backs to roost. They rested in a slumped position that hid their feet. They slept with their bills concealed by the feathers in the middle of the breast while holding their tail at a 45-degree angle. Dung could accumulate under a roosting site to a depth of over .
If the pigeon became alert, it would often stretch out its head and neck in line with its body and tail, then nod its head in a circular pattern. When aggravated by another pigeon, it raised its wings threateningly, but passenger pigeons almost never actually fought. The pigeon bathed in shallow water, and afterwards lay on each side in turn and raised the opposite wing to dry it.
The passenger pigeon drank at least once a day, typically at dawn, by fully inserting its bill into lakes, small ponds, and streams. Pigeons were seen perching on top of each other to access water, and if necessary, the species could alight on open water to drink. One of the primary causes of natural mortality was the weather, and every spring many individuals froze to death after migrating north too early. In captivity, a passenger pigeon was capable of living at least 15 years;
The passenger pigeon foraged in flocks of tens or hundreds of thousands of individuals that overturned leaves, dirt, and snow with their bills in search of food. One observer described the motion of such a flock in search of mast as having a rolling appearance, as birds in the back of the flock flew overhead to the front of the flock, dropping leaves and grass in flight. The flocks had wide leading edges to better scan the landscape for food sources.
When nuts on a tree loosened from their caps, a pigeon would land on a branch and, while flapping vigorously to stay balanced, grab the nut, pull it loose from its cap, and swallow it whole. Collectively, a foraging flock was capable of removing nearly all fruits and nuts from their path. Birds in the back of the flock flew to the front in order to pick over unsearched ground; however, birds never ventured far from the flock and hurried back if they became isolated. It is believed that the pigeons used social cues to identify abundant sources of food, and a flock of pigeons that saw others feeding on the ground often joined them. During the day, the birds left the roosting forest to forage on more open land. They regularly flew away from their roost daily in search of food, and some pigeons reportedly traveled as far as , leaving the roosting area early and returning at night.
The passenger pigeon's very elastic mouth and throat and a joint in the lower bill enabled it to swallow acorns whole. It could store large quantities of food in its
Other than finding roosting sites, the migrations of the passenger pigeon were connected with finding places appropriate for this 
After observing captive birds, Wallace Craig found that this species did less charging and strutting than other pigeons (as it was awkward on the ground), and thought it probable that no food was transferred during their brief billing (unlike in other pigeons), and he therefore considered Audubon's description partially based on analogy with other pigeons as well as imagination.
Nests were built immediately after pair formation and took two to four days to construct; this process was highly synchronized within a colony. The female chose the nesting site by sitting on it and flicking her wings. The male then carefully selected nesting materials, typically twigs, and handed them to the female over her back. The male then went in search of more nesting material while the female constructed the nest beneath herself. Nests were built between above the ground, though typically above , and were made of 70 to 110 twigs woven together to create a loose, shallow bowl through which the egg could easily be seen. This bowl was then typically lined with finer twigs. The nests were about wide, high, and deep. Though the nest has been described as crude and flimsy compared to those of many other birds, remains of nests could be found at sites where nesting had taken place several years prior. Nearly every tree capable of supporting nests had them, often more than 50 per tree; one hemlock was recorded as holding 317 nests. The nests were placed on strong branches close to the tree trunks. Some accounts state that ground under the nesting area looked as if it had been swept clean, due to all the twigs being collected at the same time, yet this area would also have been covered in dung. As both sexes took care of the nest, the pairs were 
Generally, the eggs were laid during the first two weeks of April across the pigeon's range. Each female laid its egg immediately or almost immediately after the nest was completed; sometimes the pigeon was forced to lay it on the ground if the nest was not complete. The normal clutch size appears to have been a single egg, but there is some uncertainty about this, as two have also been reported from the same nests. Occasionally, a second female laid its egg in another female's nest, resulting in two eggs being present. The egg was white and oval shaped and averaged in size. If the egg was lost, it was possible for the pigeon to lay a replacement egg within a week. A whole colony was known to re-nest after a snowstorm forced them to abandon their original colony. Both parents incubated The egg for 12 to 14 days, with the male incubating it from midmorning to midafternoon and the female incubating it the rest of the time.
Upon hatching, the nestling (or squab) was blind and sparsely covered with yellow, hairlike down. The nestling developed quickly and within 14 days weighed as much as its parents. During this brooding period both parents took care of the nestling, with the male attending in the middle of the day and the female at other times. The nestlings were fed crop milk (a substance similar to
Nesting colonies attracted large numbers of predators, including
The passenger pigeon was featured in the writings of many significant early naturalists, as well as accompanying illustrations. Mark Catesby's 1731 illustration, the first published depiction of this bird, is somewhat crude, according to some later commentators. The original watercolor that the engraving is based on was bought by the British royal family in 1768, along with the rest of Catesby's watercolors. The naturalists Alexander Wilson and John James Audubon both witnessed large pigeon migrations first hand, and published detailed accounts wherein both attempted to deduce the total number of birds involved. The most famous and often reproduced depiction of the passenger pigeon is Audubon's illustration (handcolored
The passenger pigeon was an important source of food for the people of North America. Native Americans ate pigeons, and tribes near nesting colonies would sometimes move to live closer to them and eat the juveniles, killing them at night with long poles. Many Native Americans were careful not to disturb the adult pigeons, and instead ate only the juveniles as they were afraid that the adults might desert their nesting grounds; in some tribes, disturbing the adult pigeons was considered a crime. Away from the nests, large nets were used to capture adult pigeons, sometimes up to 800 at a time. Low-flying pigeons could be killed by throwing sticks or stones. At one site in 
What may be the earliest account of Europeans hunting passenger pigeons dates to January 1565, when the French explorer René Laudonnière wrote of killing close to 10,000 of them around 
Humans used a wide variety of other methods to capture and kill passenger pigeons. Nets were propped up to allow passenger pigeons entry, and then closed by knocking loose the stick that supported the opening, trapping twenty or more pigeons inside. Tunnel nets were also used to great effect, and one particularly large net was capable of catching 3,500 pigeons at a time. These nets were used by many farmers on their own property as well as by professional trappers. Food would be placed on the ground near the nets to attract the pigeons. 
By the mid-19th century,
Most captive passenger pigeons were kept for exploitative purposes, but some were housed in zoos and aviaries. Audubon alone claimed to have brought 350 birds to England in 1830, distributing them among various noblemen, and the species is also known to have been kept at 
The Cincinnati Zoo, one of the oldest zoos in the United States, kept passenger pigeons from its beginning in 1875. The zoo kept more than twenty individuals in a cage. Passenger pigeons do not appear to have been kept at the zoo due to their rarity, but to enable guests to have a closer look at a native species. Recognizing the decline of the wild populations, Whitman and the Cincinnati Zoo consistently strove to breed the surviving birds, including attempts at making a rock dove foster passenger pigeon eggs. In 1902, Whitman gave a female passenger pigeon to the zoo; this was possibly the individual later known as Martha, which would become the last living member of the species. Other sources argue that Martha was hatched at the Cincinnati Zoo, lived there for 25 years, and was the descendant of three pairs of passenger pigeons purchased by the zoo in 1877. It is thought this individual was named Martha because her last cage mate was named George, thereby honoring
The 2014 genetic study that found natural fluctuations in population numbers prior to human arrival also concluded that the species routinely recovered from lows in the population, and suggested that one of these lows may have coincided with the intensified hunting by humans in the 1800s, a combination which would have led to the rapid extinction of the species. A similar scenario may also explain the rapid extinction of the Rocky Mountain locust (''Melanoplus spretus'') during the same period. It has also been suggested that after the population was thinned out, it would be harder for few or solitary birds to locate suitable feeding areas. In addition to the birds killed or driven away by hunting during breeding seasons, many nestlings were also orphaned before being able to fend for themselves. Other, less convincing contributing factors have been suggested at times, including mass drownings,
Today, at least 1,532 passenger pigeon skins (along with 16 skeletons) still exist, spread across many institutions all over the world. It has been suggested that the passenger pigeon should be revived when available technology allows it (a concept which has been termed "
Project Passenger Pigeon: Lessons from the Past for a Sustainable Future
The Demise of the Passenger Pigeon
(as broadcast on
360-degree view of Martha, the last passenger pigeon
(
sexually dimorphic
Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
, and having iridescent
Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear gradually to change colour as the angle of view or the angle of illumination changes. Iridescence is caused by wave interference of light in microstruc ...
neck feathers and a smaller clutch
A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does th ...
. In a 2002 study by American geneticist Beth Shapiro et al., museum specimens of the passenger pigeon were included in an ancient DNA
Ancient DNA (aDNA) is DNA isolated from ancient sources (typically Biological specimen, specimens, but also environmental DNA). Due to degradation processes (including Crosslinking of DNA, cross-linking, deamination and DNA fragmentation, fragme ...
analysis for the first time (in a paper focusing mainly on the dodo
The dodo (''Raphus cucullatus'') is an extinction, extinct flightless bird that was endemism, endemic to the island of Mauritius, which is east of Madagascar in the Indian Ocean. The dodo's closest relative was the also-extinct and flightles ...
), and it was found to be the sister taxon
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and ...
of the cuckoo-dove genus '' Macropygia''. The ''Zenaida'' doves were instead shown to be related to the quail-doves of the genus '' Geotrygon'' and the '' Leptotila'' doves.
A more extensive 2010 study instead showed that the passenger pigeon was most closely related to the New World '' Patagioenas'' pigeons, including the band-tailed pigeon (''P. fasciata'') of western North America, which are related to the Southeast Asian species in the genera '' Turacoena'', ''Macropygia'', and '' Reinwardtoena''. This clade
In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...
is also related to the ''Columba'' and ''Streptopelia
''Streptopelia'' (collared doves and turtle doves) is a genus of 15 species of birds in the pigeon and dove family Columbidae native to the Old World in Africa, Europe, and Asia. These are mainly slim, small to medium-sized species. The upperpar ...
'' doves of the Old World (collectively termed the "typical pigeons and doves"). The authors of the study suggested that the ancestors of the passenger pigeon may have colonized the New World from South East Asia by flying across the Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...
, or perhaps across Beringia
Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 70th parallel north, 72° north latitude in the Chukchi Sea; and on the south ...
in the north.
In a 2012 study, the nuclear DNA
Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. ...
of the passenger pigeon was analyzed for the first time, and its relationship with the ''Patagioenas'' pigeon was confirmed. In contrast to the 2010 study, these authors suggested that their results could indicate that the ancestors of the passenger pigeon and its Old World relatives may have originated in the Neotropical region of the New World.
The cladogram
A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...
below follows the 2012 DNA study showing the position of the passenger pigeon among its closest relatives:
DNA in old museum specimens is often degraded and fragmentary, and passenger pigeon specimens have been used in various studies to discover improved methods of analyzing and assembling genomes from such material. DNA samples are often taken from the toe pads of bird skins in museums, as this can be done without causing significant damage to valuable specimens. The passenger pigeon had no known subspecies. Hybridization occurred between the passenger pigeon and the Barbary dove (''Streptopelia risoria'') in the aviary of Charles Otis Whitman (who owned many of the last captive birds around the turn of the 20th century, and kept them with other pigeon species) but the offspring were infertile.
Etymology
The genus name, ''Ectopistes'', translates as "moving about" or "wandering", while the specific name, ''migratorius'', indicates its migratory habits. The full binomial can thus be translated as "migratory wanderer". The English common name "passenger pigeon" derives from the French word ', which means "to pass by" in a fleeting manner. While the pigeon was extant, the name "passenger pigeon" was used interchangeably with "wild pigeon". p. 251. The bird also gained some less-frequently used names, including blue pigeon, merne rouck pigeon, wandering long-tailed dove, and wood pigeon. In the 18th century, the passenger pigeon was known as ''tourte'' inNew France
New France (, ) was the territory colonized by Kingdom of France, France in North America, beginning with the exploration of the Gulf of Saint Lawrence by Jacques Cartier in 1534 and ending with the cession of New France to Kingdom of Great Br ...
(in modern Canada), but to the French in Europe it was known as ''tourtre''. In modern French, the bird is known as ''tourte voyageuse'' or ''pigeon migrateur'', among other names.
In the Native American Algonquian languages
The Algonquian languages ( ; also Algonkian) are a family of Indigenous languages of the Americas and most of the languages in the Algic language family are included in the group. The name of the Algonquian language family is distinguished from ...
, the pigeon was called ''amimi'' by the Lenape
The Lenape (, , ; ), also called the Lenni Lenape and Delaware people, are an Indigenous peoples of the Northeastern Woodlands, Indigenous people of the Northeastern Woodlands, who live in the United States and Canada.
The Lenape's historica ...
, ' by the Ojibwe
The Ojibwe (; Ojibwe writing systems#Ojibwe syllabics, syll.: ᐅᒋᐺ; plural: ''Ojibweg'' ᐅᒋᐺᒃ) are an Anishinaabe people whose homeland (''Ojibwewaki'' ᐅᒋᐺᐘᑭ) covers much of the Great Lakes region and the Great Plains, n ...
, and ' by the Kaskaskia
The Kaskaskia were a historical Indigenous people of the Northeastern Woodlands. They were one of about a dozen cognate tribes that made up the Illiniwek Confederation, also called the Illinois Confederation. Their longstanding homeland was in ...
Illinois
Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...
. Other names in indigenous American languages include ' in Mohawk, and ', or "lost dove", in Choctaw
The Choctaw ( ) people are one of the Indigenous peoples of the Southeastern Woodlands of the United States, originally based in what is now Louisiana, Mississippi and Alabama. The Choctaw language is a Western Muskogean language. Today, Choct ...
. The Seneca people
The Seneca ( ; ) are a group of Indigenous Iroquoian-speaking people who historically lived south of Lake Ontario, one of the five Great Lakes in North America. Their nation was the farthest to the west within the Six Nations or Iroquois Leag ...
called the pigeon ', meaning "big bread", as it was a source of food for their tribes. Chief Simon Pokagon of the Potawatomi
The Potawatomi (), also spelled Pottawatomi and Pottawatomie (among many variations), are a Native American tribe of the Great Plains, upper Mississippi River, and western Great Lakes region. They traditionally speak the Potawatomi language, ...
stated that his people called the pigeon ', and that the Europeans did not adopt native names for the bird, as it reminded them of their domesticated pigeons, instead calling them "wild" pigeons, as they called the native peoples "wild" men.
Description
The passenger pigeon wassexually dimorphic
Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
in size and coloration. It weighed between . The adult male was about in length. It had a bluish-gray head, nape, and hindneck. On the sides of the neck and the upper mantle were iridescent display feathers that have variously been described as being a bright bronze, violet, or golden-green, depending on the angle of the light. The upper back and wings were a pale or slate gray tinged with olive brown, that turned into grayish-brown on the lower wings. The lower back and rump were a dark blue-gray that became grayish-brown on the upper tail- covert feathers. The greater and median wing-covert feathers were pale gray, with a small number of irregular black spots near the end. The primary and secondary feathers of the wing were a blackish-brown with a narrow white edge on the outer side of the secondaries. The two central tail feathers were brownish gray, and the rest were white.
The tail pattern was distinctive as it had white outer edges with blackish spots that were prominently displayed in flight. The lower throat and breast were richly pinkish-rufous
Rufous () is a color that may be described as reddish-brown or brownish- red, as of rust or oxidised iron. The first recorded use of ''rufous'' as a color name in English was in 1782. However, the color is also recorded earlier in 1527 as a d ...
, grading into a paler pink further down, and into white on the abdomen and undertail covert feathers. The undertail coverts also had a few black spots. The bill was black, while the feet and legs were a bright coral red. It had a carmine
Carmine ()also called cochineal (when it is extracted from the Cochineal, cochineal insect), cochineal extract, crimson Lake pigment, lake, or carmine lake is a pigment of a bright-red color obtained from the aluminium coordination complex, compl ...
-red iris surrounded by a narrow purplish-red eye-ring. The wing of the male measured , the tail , the bill , and the tarsus was .
The adult female passenger pigeon was slightly smaller than the male at in length. It was duller than the male overall, and was a grayish-brown on the forehead, crown, and nape down to the scapular
A scapular () is a Western Christian garment suspended from the shoulders. There are two types of scapulars, the monastic and devotional scapular; both forms may simply be referred to as "scapular". As an object of popular piety, a scapular ...
s, and the feathers on the sides of the neck had less iridescence
Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear gradually to change colour as the angle of view or the angle of illumination changes. Iridescence is caused by wave interference of light in microstru ...
than those of the male. The lower throat and breast were a buff-gray that developed into white on the belly and undertail-coverts. It was browner on the upperparts and paler buff brown and less rufous on the underparts than the male. The wings, back, and tail were similar in appearance to those of the male except that the outer edges of the primary feathers were edged in buff or rufous buff. The wings had more spotting than those of the male. The tail was shorter than that of the male, and the legs and feet were a paler red. The iris was orange red, with a grayish blue, naked orbital ring. The wing of the female was , the tail , the bill , and the tarsus was .
The juvenile passenger pigeon was similar in plumage
Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
to the adult female, but lacked the spotting on the wings, and was a darker brownish-gray on the head, neck, and breast. The feathers on the wings had pale gray fringes (also described as white tips), giving it a scaled look. The secondaries were brownish-black with pale edges, and the tertial feathers had a rufous wash. The primaries were also edged with a rufous-brown color. The neck feathers had no iridescence. The legs and feet were dull red, and the iris was brownish, and surrounded by a narrow carmine ring. The plumage of the sexes was similar during their first year.
Of the hundreds of surviving skins, only one appears to be aberrant in coloran adult female from the collection of Walter Rothschild, Natural History Museum at Tring
The Natural History Museum at Tring was the private museum of Lionel Walter, 2nd Baron Rothschild; today it is under the control of the Natural History Museum, London. It houses one of the finest collections of stuffed mammals, birds, reptil ...
. It is a washed brown on the upper parts, wing covert, secondary feathers, and tail (where it would otherwise have been gray), and white on the primary feathers and underparts. The normally black spots are brown, and it is pale gray on the head, lower back, and upper-tail covert feathers, yet the iridescence is unaffected. The brown mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, ...
is a result of a reduction in eumelanin
Melanin (; ) is a family of biomolecules organized as oligomers or polymers, which among other functions provide the pigments of many organisms. Melanin pigments are produced in a specialized group of cells known as melanocytes.
There are ...
, due to incomplete synthesis (oxidation
Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...
) of this pigment
A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...
. This sex-linked mutation is common in female wild birds, but it is thought the white feathers of this specimen are instead the result of bleaching due to exposure to sunlight.
The passenger pigeon was physically adapted for speed, endurance, and maneuverability in flight, and has been described as having a streamlined version of the typical pigeon shape, such as that of the generalized rock dove
The rock dove (''Columba livia''), also sometimes known as "rock pigeon" or "common pigeon", is a member of the bird family Columbidae (doves and pigeons). In common usage, it is often simply referred to as the "pigeon", although the rock dov ...
(''Columba livia''). The wings were very long and pointed, and measured from the wing-chord to the primary feathers, and to the secondaries. The tail, which accounted for much of its overall length, was long and wedge-shaped (or graduated), with two central feathers longer than the rest. The body was slender and narrow, and the head and neck were small.
The internal anatomy of the passenger pigeon has rarely been described. Robert W. Shufeldt found little to differentiate the bird's osteology from that of other pigeons when examining a male skeleton in 1914, but Julian P. Hume noted several distinct features in a more detailed 2015 description. The pigeon's particularly large breast muscles indicated a powerful flight ( musculus pectoralis major for downstroke and the smaller musculus supracoracoideus for upstroke). The coracoid
A coracoid is a paired bone which is part of the shoulder assembly in all vertebrates except therian mammals (marsupials and placentals). In therian mammals (including humans), a coracoid process is present as part of the scapula, but this is n ...
bone (which connects the scapula
The scapula (: scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either side ...
, furcula, and sternum
The sternum (: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major bl ...
) was large relative to the size of the bird, , with straighter shafts and more robust articular ends than in other pigeons. The furcula had a sharper V-shape and was more robust, with expanded articular ends. The scapula was long, straight, and robust, and its distal
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...
end was enlarged. The sternum was very large and robust compared to that of other pigeons; its keel
The keel is the bottom-most longitudinal structural element of a watercraft, important for stability. On some sailboats, it may have a fluid dynamics, hydrodynamic and counterbalancing purpose as well. The keel laying, laying of the keel is often ...
was deep. The overlapping uncinate processes, which stiffen the ribcage, were very well developed. The wing bones (humerus
The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...
, radius
In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...
, ulna
The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...
, and carpometacarpus
The carpometacarpus is a bone found in the hands of birds. It results from the fusion of the carpal and metacarpal bone, and is essentially a single fused bone between the wrist and the knuckles. It is a smallish bone in most birds, generally fla ...
) were short but robust compared to other pigeons. The leg bones were similar to those of other pigeons.
Vocalizations
The noise produced by flocks of passenger pigeons was described as deafening, audible for miles away, and the bird's voice as loud, harsh, and unmusical. It was also described by some as clucks, twittering, and cooing, and as a series of low notes, instead of an actual song. The birds apparently made croaking noises when building nests, and bell-like sounds when mating. During feeding, some individuals would give alarm calls
In animal communication, an alarm signal is an antipredator adaptation in the form of signals emitted by social animals in response to danger. Many primates and birds have elaborate alarm calls for warning conspecifics of approaching predators ...
when facing a threat, and the rest of the flock would join the sound while taking off. pp. 30–47.
In 1911, American behavioral scientist Wallace Craig
Wallace Craig (1876–1954) was an American experimental psychologist and behavior scientist. He provided a conceptual framework for the study of behavior organization and is regarded as one of the founders of ethology. Craig experimentally stu ...
published an account of the gestures and sounds of this species as a series of descriptions and musical notation
Musical notation is any system used to visually represent music. Systems of notation generally represent the elements of a piece of music that are considered important for its performance in the context of a given musical tradition. The proce ...
s, based on observation of C. O. Whitman's captive passenger pigeons in 1903. Craig compiled these records to assist in identifying potential survivors in the wild (as the physically similar mourning doves could otherwise be mistaken for passenger pigeons), while noting this "meager information" was likely all that would be left on the subject. According to Craig, one call was a simple harsh "keck" that could be given twice in succession with a pause in between. This was said to be used to attract the attention of another pigeon. Another call was a more frequent and variable scolding. This sound was described as "kee-kee-kee-kee" or "tete! tete! tete!", and was used to call either to its mate or towards other creatures it considered to be enemies. One variant of this call, described as a long, drawn-out "tweet", could be used to call down a flock of passenger pigeons passing overhead, which would then land in a nearby tree. "Keeho" was a soft cooing that, while followed by louder "keck" notes or scolding, was directed at the bird's mate. A nesting passenger pigeon would also give off a stream of at least eight mixed notes that were both high and low in tone and ended with "keeho". Overall, female passenger pigeons were quieter and called infrequently. Craig suggested that the loud, strident voice and "degenerated" musicality was the result of living in populous colonies where only the loudest sounds could be heard.
Distribution and habitat
The passenger pigeon was found across most of North America east of the Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...
, from the Great Plains
The Great Plains is a broad expanse of plain, flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include th ...
to the Atlantic coast in the east, to the south of Canada in the north, and the north of Mississippi in the southern United States, coinciding with its primary habitat, the eastern deciduous forests
In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, after flo ...
. Within this range, it constantly migrated in search of food and shelter. It is unclear if the birds favored particular trees and terrain, but they were possibly not restricted to one type, as long as their numbers could be supported. It originally bred from the southern parts of eastern and central Canada south to eastern Kansas, Oklahoma, Mississippi, and Georgia in the United States, but the primary breeding range was in southern Ontario and the Great Lakes
The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, H ...
states south through states north of the Appalachian Mountains
The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions associated with the mountain range, and its surrounding terrain ...
. Though the western forests were ecologically similar to those in the east, these were occupied by band-tailed pigeons, which may have kept out the passenger pigeons through competitive exclusion.
The passenger pigeon wintered from Arkansas, Tennessee, and North Carolina south to Texas, the Gulf Coast, and northern Florida, though flocks occasionally wintered as far north as southern Pennsylvania and Connecticut. It preferred to winter in large swamps, particularly those with alder
Alders are trees of the genus ''Alnus'' in the birch family Betulaceae. The genus includes about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species ex ...
trees; if swamps were not available, forested areas, particularly with pine
A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae.
''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as cu ...
trees, were favored roosting sites. There were also sightings of passenger pigeons outside of its normal range, including in several Western states, Bermuda
Bermuda is a British Overseas Territories, British Overseas Territory in the Atlantic Ocean, North Atlantic Ocean. The closest land outside the territory is in the American state of North Carolina, about to the west-northwest.
Bermuda is an ...
, Cuba
Cuba, officially the Republic of Cuba, is an island country, comprising the island of Cuba (largest island), Isla de la Juventud, and List of islands of Cuba, 4,195 islands, islets and cays surrounding the main island. It is located where the ...
, and Mexico
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
, particularly during severe winters. It has been suggested that some of these extralimital records may have been due to the paucity of observers rather than the actual extent of passenger pigeons; North America was then unsettled country, and the bird may have appeared anywhere on the continent except for the far west. There were also records of stragglers in Scotland, Ireland, and France, although these birds may have been escaped captives, or the records incorrect.
More than 130 passenger pigeon fossils have been found scattered across 25 US states, including in the La Brea Tar Pits
La Brea Tar Pits comprise an active Paleontological site, paleontological research site in urban Los Angeles. Hancock Park was formed around a group of tar pits where natural Bitumen, asphalt (also called asphaltum, bitumen, or pitch; ''brea'' ...
of California. These records date as far back as 100,000 years ago in the Pleistocene
The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...
era, during which the pigeon's range extended to several western states that were not a part of its modern range. The abundance of the species in these regions and during this time is unknown.
Ecology and behavior
The passenger pigeon wasnomad
Nomads are communities without fixed habitation who regularly move to and from areas. Such groups include hunter-gatherers, pastoral nomads (owning livestock), tinkers and trader nomads. In the twentieth century, the population of nomadic pa ...
ic, constantly migrating in search of food, shelter, or nesting grounds. In his 1831 ''Ornithological Biography'', American naturalist and artist John James Audubon
John James Audubon (born Jean-Jacques Rabin, April 26, 1785 – January 27, 1851) was a French-American Autodidacticism, self-trained artist, natural history, naturalist, and ornithology, ornithologist. His combined interests in art and ornitho ...
described a migration he observed in 1813 as follows:
These flocks were frequently described as being so dense that they blackened the sky and as having no sign of subdivisions. The flocks ranged from only above the ground in windy conditions to as high as . These migrating flocks were typically in narrow columns that twisted and undulated, and they were reported as being in nearly every conceivable shape. A skilled flyer, the passenger pigeon is estimated to have averaged during migration. It flew with quick, repeated flaps that increased the bird's velocity the closer the wings got to the body. It was equally adept and quick flying through a forest as through open space. A flock was also adept at following the lead of the pigeon in front of it, and flocks swerved together to avoid a predator. When landing, the pigeon flapped its wings repeatedly before raising them at the moment of landing. The pigeon was awkward when on the ground, and moved around with jerky, alert steps.
The passenger pigeon was one of the most social of all land birds. Estimated to have numbered three to five billion at the height of its population, it may have been the most numerous bird on Earth; researcher Arlie W. Schorger believed that it accounted for between 25 and 40 percent of the total land bird population in the United States. The passenger pigeon's historic population is roughly the equivalent of the number of birds that overwinter in the United States every year in the early 21st century. Even within their range, the size of individual flocks could vary greatly. In November 1859, Henry David Thoreau
Henry David Thoreau (born David Henry Thoreau; July 12, 1817May 6, 1862) was an American naturalist, essayist, poet, and philosopher. A leading Transcendentalism, transcendentalist, he is best known for his book ''Walden'', a reflection upon sim ...
, writing in Concord, Massachusetts
Concord () is a town in Middlesex County, Massachusetts, United States. In the 2020 United States census, 2020 census, the town population was 18,491. The United States Census Bureau considers Concord part of Greater Boston. The town center is n ...
, noted that "quite a little flock of assengerpigeons bred here last summer," while only seven years later, in 1866, one flock in southern Ontario
Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...
was described as being wide and long, took 14 hours to pass, and held in excess of 3.5 billion birds. Such a number would likely represent a large fraction of the entire population at the time, or perhaps all of it. Most estimations of numbers were based on single migrating colonies, and it is unknown how many of these existed at a given time. American writer Christopher Cokinos has suggested that if the birds flew single file, they would have stretched around the Earth 22 times.
A 2014 genetic study (based on coalescent theory
Coalescent theory is a Scientific modelling, model of how alleles sampled from a population may have originated from a most recent common ancestor, common ancestor. In the simplest case, coalescent theory assumes no genetic recombination, recombina ...
and on "sequences from most of the genome
A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...
" of three individual passenger pigeons) suggested that the passenger pigeon population experienced dramatic fluctuations across the last million years, due to their dependence on availability of mast (which itself fluctuates). The study suggested the bird was not always abundant, mainly persisting at around 1/10,000 the amount of the several billions estimated in the 1800s, with vastly larger numbers present during outbreak phases. Some early accounts also suggest that the appearance of flocks in great numbers was an irregular occurrence. These large fluctuations in population may have been the result of a disrupted ecosystem and have consisted of outbreak populations much larger than those common in pre-European times. The authors of the 2014 genetic study note that a similar analysis of the human population size arrives at an "effective population size
The effective population size (''N'e'') is the size of an idealised population that would experience the same rate of genetic drift as the real population. Idealised populations are those following simple one- locus models that comply with ass ...
" of between 9,000 and 17,000 individuals (or approximately 1/550,000th of the peak total human population size of 7 billion cited in the study).
For a 2017 genetic study, the authors sequenced the genome
A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...
s of two additional passenger pigeons, as well as analyzing the mitochondrial DNA
Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...
of 41 individuals. This study found evidence that the passenger-pigeon population had been stable for at least the previous 20,000 years. The study also found that the size of the passenger pigeon population over that time period was larger than the found in the 2014 genetic study. However, the 2017 study's "conservative" estimate of an "effective population size
The effective population size (''N'e'') is the size of an idealised population that would experience the same rate of genetic drift as the real population. Idealised populations are those following simple one- locus models that comply with ass ...
" of 13 million birds is still only about 1/300th of the bird's estimated historic population of approximately 3–5 billion before their "19th century decline and eventual extinction." A similar study inferring human population size from genetics (published in 2008, and using human mitochondrial DNA and Bayesian coalescent
''Coalescent'' is a science-fiction novel by Stephen Baxter. It is part one of the '' Destiny's Children'' series. The story is set in two main time periods: modern Britain, when George Poole finds that he has a previously unknown sister and ...
inference methods) showed considerable accuracy in reflecting overall patterns of human population growth as compared to data deduced by other means—though the study arrived at a human effective population size
The effective population size (''N'e'') is the size of an idealised population that would experience the same rate of genetic drift as the real population. Idealised populations are those following simple one- locus models that comply with ass ...
(as of 1600 AD, for Africa, Eurasia, and the Americas combined) that was roughly 1/1000 of the census population estimate for the same time and area based on anthropological and historical evidence.
The 2017 passenger-pigeon genetic study also found that, in spite of its large population size, the genetic diversity was very low in the species. The authors suggested that this was a side-effect of natural selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generation ...
, which theory and previous empirical studies suggested could have a particularly great impact on species with very large and cohesive populations. Natural selection can reduce genetic diversity over extended regions of a genome through 'selective sweep
In genetics, a selective sweep is the process through which a new beneficial mutation that increases its frequency and becomes fixed (i.e., reaches a frequency of 1) in the population leads to the reduction or elimination of genetic variation amon ...
s' or ' background selection'. The authors found evidence of a faster rate of adaptive evolution and faster removal of harmful mutations in passenger pigeons compared to band-tailed pigeons, which are some of passenger pigeons' closest living relatives. They also found evidence of lower genetic diversity in regions of the passenger pigeon genome that have lower rates of genetic recombination
Genetic recombination (also known as genetic reshuffling) is the exchange of genetic material between different organisms which leads to production of offspring with combinations of traits that differ from those found in either parent. In eukaryot ...
. This is expected if natural selection, via selective sweep
In genetics, a selective sweep is the process through which a new beneficial mutation that increases its frequency and becomes fixed (i.e., reaches a frequency of 1) in the population leads to the reduction or elimination of genetic variation amon ...
s or background selection, reduced their genetic diversity, but not if population instability did. The study concluded that earlier suggestion that population instability contributed to the extinction of the species was invalid. Evolutionary biologist A. Townsend Peterson said of the two passenger-pigeon genetic studies (published in 2014 and 2017) that, though the idea of extreme fluctuations in the passenger-pigeon population was "deeply entrenched," he was persuaded by the 2017 study's argument, due to its "in-depth analysis" and "massive data resources."
A communally roosting species, the passenger pigeon chose roosting sites that could provide shelter and enough food to sustain their large numbers for an indefinite period. The time spent at one roosting site may have depended on the extent of human persecution, weather conditions, or other, unknown factors. Roosts ranged in size and extent, from a few acres to or greater. Some roosting areas would be reused for subsequent years, others would only be used once. The passenger pigeon roosted in such numbers that even thick tree branches would break under the strain. The birds frequently piled on top of each other's backs to roost. They rested in a slumped position that hid their feet. They slept with their bills concealed by the feathers in the middle of the breast while holding their tail at a 45-degree angle. Dung could accumulate under a roosting site to a depth of over .
If the pigeon became alert, it would often stretch out its head and neck in line with its body and tail, then nod its head in a circular pattern. When aggravated by another pigeon, it raised its wings threateningly, but passenger pigeons almost never actually fought. The pigeon bathed in shallow water, and afterwards lay on each side in turn and raised the opposite wing to dry it.
The passenger pigeon drank at least once a day, typically at dawn, by fully inserting its bill into lakes, small ponds, and streams. Pigeons were seen perching on top of each other to access water, and if necessary, the species could alight on open water to drink. One of the primary causes of natural mortality was the weather, and every spring many individuals froze to death after migrating north too early. In captivity, a passenger pigeon was capable of living at least 15 years; Martha
Martha (Aramaic language, Aramaic: מָרְתָא) is a Bible, biblical figure described in the Gospels of Gospel of Luke, Luke and Gospel of John, John. Together with her siblings Lazarus of Bethany, Lazarus and Mary of Bethany, she is descr ...
, the last known living passenger pigeon, was at least 17 and possibly as old as 29 when she died. It is undocumented how long wild pigeons lived.
The bird is believed to have played a significant ecological role in the composition of pre-Columbian
In the history of the Americas, the pre-Columbian era, also known as the pre-contact era, or as the pre-Cabraline era specifically in Brazil, spans from the initial peopling of the Americas in the Upper Paleolithic to the onset of European col ...
forests of eastern North America. For instance, while the passenger pigeon was extant, forests were dominated by white oaks. This species germinated in the fall, therefore making its seeds almost useless as a food source during the spring breeding season, while red oaks produced acorns during the spring, which the pigeons devoured. The absence of the passenger pigeon's seed consumption may have contributed to the modern dominance of red oaks. Due to the immense amount of dung present at roosting sites, few plants grew for years after the pigeons left. Also, the accumulation of flammable debris (such as limbs broken from trees and foliage killed by excrement) at these sites may have increased both the frequency and intensity of forest fires A forest fire
A wildfire, forest fire, or a bushfire is an unplanned and uncontrolled fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identified as a bushfire ( in Au ...
, which would have favored fire-tolerant species, such as bur oaks, black oaks, and white oaks over less fire-tolerant species, such as red oaks, thus helping to explain the change in the composition of eastern forests since the passenger pigeon's extinction (from white oaks, bur oaks, and black oaks predominating in presettlement forests, to the "dramatic expansion" of red oaks today).
A study released in 2018 concluded that the "vast numbers" of passenger pigeons present for "tens of thousands of years" would have influenced the evolution of the tree species whose seeds they ate. Those masting trees that produced seeds during the spring nesting season (such as red oaks) evolved so that some portion of their seeds would be too large for passenger pigeons to swallow (thus allowing some of their seeds to escape predation and grow new trees). White oak, in contrast, with its seeds sized consistently in the edible range, evolved an irregular masting pattern that took place in the fall, when fewer passenger pigeons would have been present. The study further concluded that this allowed white oaks to be the dominant tree species in regions where passenger pigeons were commonly present in the spring.
With the large numbers in passenger pigeon flocks, the excrement they produced was enough to destroy surface-level vegetation at long-term roosting sites, while adding high quantities of nutrients to the ecosystem
An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...
. Because of this—along with the breaking of tree limbs under their collective weight and the great amount of mast they consumed—passenger pigeons are thought to have influenced both the structure of eastern forests and the composition of the species present there. Due to these influences, some ecologists have considered the passenger pigeon a keystone species
A keystone species is a species that has a disproportionately large effect on its natural environment relative to its abundance. The concept was introduced in 1969 by the zoologist Robert T. Paine. Keystone species play a critical role in main ...
, with the disappearance of their vast flocks leaving a major gap in the ecosystem. Their role in creating forest disturbances has been linked to greater vertebrate diversity in forests by creating more niches for animals to fill. To help fill that ecological gap, it has been proposed that modern land managers attempt to replicate some of their effects on the ecosystem by creating openings in forest canopies to provide more understory
In forestry and ecology, understory (American English), or understorey (English in the Commonwealth of Nations, Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the Canopy (biology), forest ca ...
light.
The American chestnut
The American chestnut (''Castanea dentata'') is a large, fast-growing deciduous tree of the Fagaceae, beech family native to eastern North America. As is true of all species in the genus ''Chestnut, Castanea'', the American chestnut produces Bur ...
trees that provided much of the mast on which the passenger pigeon fed was itself almost driven to extinction by an imported Asian fungus (chestnut blight
The pathogenic fungus ''Cryphonectria parasitica'' (formerly ''Endothia parasitica'') is a member of the Ascomycota (sac fungi). This necrotrophic fungus is native to East Asia and South East Asia and was introduced into Europe and North America ...
) around 1905. As many as thirty billion trees are thought to have died as a result in the following decades, but this did not affect the passenger pigeon, which was already extinct in the wild at the time.
After the disappearance of the passenger pigeon, the population of another acorn feeding species, the white-footed mouse
The white-footed mouse (''Peromyscus leucopus'') is a rodent native to North America from southern Canada to the southwestern United States and Mexico. It is a species of the genus ''Peromyscus'', a closely related group of New World mice often ...
, grew exponentially because of the increased availability of the seeds of the oak, beech, and chestnut trees. It has been speculated that the extinction of passenger pigeons may have increased the prevalence of tick-borne lyme disease
Lyme disease, also known as Lyme borreliosis, is a tick-borne disease caused by species of ''Borrelia'' bacteria, Disease vector, transmitted by blood-feeding ticks in the genus ''Ixodes''. It is the most common disease spread by ticks in th ...
in modern times as white-footed mice are the reservoir hosts of ''Borrelia burgdorferi
''Borrelia burgdorferi'' is a bacterial species of the spirochete class in the genus '' Borrelia'', and is one of the causative agents of Lyme disease in humans. Along with a few similar genospecies, some of which also cause Lyme disease, it m ...
''.
Diet
Beech
Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...
es and oak
An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...
s produced the mast needed to support nesting and roosting flocks. The passenger pigeon changed its diet depending on the season. In the fall, winter, and spring, it mainly ate beechnuts, acorn
The acorn is the nut (fruit), nut of the oaks and their close relatives (genera ''Quercus'', ''Notholithocarpus'' and ''Lithocarpus'', in the family Fagaceae). It usually contains a seedling surrounded by two cotyledons (seedling leaves), en ...
s, and chestnuts. During the summer, berries and softer fruits, such as blueberries
Blueberries are a widely distributed and widespread group of perennial flowering plants with blue or purple berries. They are classified in the section ''Cyanococcus'' with the genus ''Vaccinium''. Commercial blueberries—both wild (lowbush) ...
, grape
A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus ''Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters.
The cultivation of grapes began approximately 8,0 ...
s, cherries
A cherry is the fruit of many plants of the genus ''Prunus'', and is a fleshy drupe (stone fruit).
Commercial cherries are obtained from cultivars of several species, such as the sweet ''Prunus avium'' and the sour ''Prunus cerasus''. The name ...
, mulberries, pokeberries, and bunchberry, became the main objects of its consumption. It also ate worms
The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive catalogue and list of names of marine organisms.
Content
The content of the registry is edited and maintained by scien ...
, caterpillar
Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths).
As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...
s, snail
A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...
s, and other invertebrates, particularly while breeding. It took advantage of cultivated grains, particularly buckwheat
Buckwheat (''Fagopyrum esculentum'') or common buckwheat is a flowering plant in the knotweed family Polygonaceae cultivated for its grain-like seeds and as a cover crop. Buckwheat originated around the 6th millennium BCE in the region of what ...
, when it found them. It was especially fond of salt
In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...
, which it ingested either from brackish springs or salty soil.
Mast occurs in large quantities in different places at different times, and rarely in consecutive years, which is one of the reasons why the large flocks were constantly on the move. As mast is produced during autumn, there would have to be a large amount of it left by the summer, when the young were reared. It is unknown how they located this fluctuating food source, but their eyesight and flight powers helped them survey large areas for places that could provide food enough for a temporary stay.
The passenger pigeon foraged in flocks of tens or hundreds of thousands of individuals that overturned leaves, dirt, and snow with their bills in search of food. One observer described the motion of such a flock in search of mast as having a rolling appearance, as birds in the back of the flock flew overhead to the front of the flock, dropping leaves and grass in flight. The flocks had wide leading edges to better scan the landscape for food sources.
When nuts on a tree loosened from their caps, a pigeon would land on a branch and, while flapping vigorously to stay balanced, grab the nut, pull it loose from its cap, and swallow it whole. Collectively, a foraging flock was capable of removing nearly all fruits and nuts from their path. Birds in the back of the flock flew to the front in order to pick over unsearched ground; however, birds never ventured far from the flock and hurried back if they became isolated. It is believed that the pigeons used social cues to identify abundant sources of food, and a flock of pigeons that saw others feeding on the ground often joined them. During the day, the birds left the roosting forest to forage on more open land. They regularly flew away from their roost daily in search of food, and some pigeons reportedly traveled as far as , leaving the roosting area early and returning at night.
The passenger pigeon's very elastic mouth and throat and a joint in the lower bill enabled it to swallow acorns whole. It could store large quantities of food in its crop
A crop is a plant that can be grown and harvested extensively for profit or subsistence. In other words, a crop is a plant or plant product that is grown for a specific purpose such as food, Fiber, fibre, or fuel.
When plants of the same spe ...
, which could expand to about the size of an orange, causing the neck to bulge and allowing a bird quickly to grab any food it discovered. The crop was described as being capable of holding at least 17 acorns or 28 beechnuts, 11 grains of corn, 100 maple seeds, plus other material; it was estimated that a passenger pigeon needed to eat about of food a day to survive. If shot, a pigeon with a crop full of nuts would fall to the ground with a sound described as like the rattle of a bag of marbles. After feeding, the pigeons perched on branches and digested the food stored in their crop overnight with the aid of a muscular gizzard
The gizzard, also referred to as the ventriculus, gastric mill, and gigerium, is an organ found in the digestive tract of some animals, including archosaurs (birds and other dinosaurs, crocodiles, alligators, pterosaurs), earthworms, some gast ...
, which often contained gravel.
The pigeon could eat and digest of acorns per day. At the historic population of three billion passenger pigeons, this amounted to of food a day. The pigeon could regurgitate food from its crop when more desirable food became available. A 2018 study found that the dietary range of the passenger pigeon was restricted to certain sizes of seed, due to the size of its gape. This would have prevented it from eating some of the seeds of trees such as red oaks, black oaks, and the American chestnut
The American chestnut (''Castanea dentata'') is a large, fast-growing deciduous tree of the Fagaceae, beech family native to eastern North America. As is true of all species in the genus ''Chestnut, Castanea'', the American chestnut produces Bur ...
. Specifically, the study found that between 13% and 69% of red oak seeds were too large for passenger pigeons to have swallowed, that only a "small proportion" of the seeds of black oaks and American chestnuts were too large for the birds to consume, and that all white oak seeds were sized within an edible range. They also found that seeds would be completely destroyed during digestion, which therefore hindered dispersal of seeds this way. Instead, passenger pigeons may have spread seeds by regurgitation, or after dying.
Reproduction
Other than finding roosting sites, the migrations of the passenger pigeon were connected with finding places appropriate for this communally breeding
Cooperative breeding is a social system characterized by alloparental care: offspring receive care not only from their parents, but also from additional group members, often called helpers. Cooperative breeding encompasses a wide variety of group ...
bird to nest and raise its young. It is not certain how many times a year the birds bred; once seems most likely, but some accounts suggest more. The nesting period lasted around four to six weeks. The flock arrived at a nesting ground around March in southern latitudes, and some time later in more northern areas. The pigeon had no site fidelity, often choosing to nest in a different location each year. The formation of a nesting colony did not necessarily take place until several months after the pigeons arrived on their breeding grounds, typically during late March, April, or May.
The colonies, which were known as "cities", were immense, ranging from to thousands of hectares in size, and were often long and narrow in shape (L-shaped), with a few areas untouched for unknown reasons. Due to the topography, they were rarely continuous. Since no accurate data was recorded, it is not possible to give more than estimates on the size and population of these nesting areas, but most accounts mention colonies containing millions of birds. The largest nesting area ever recorded was in central Wisconsin in 1871; it was reported as covering , with the number of birds nesting there estimated to be around 136,000,000. As well as these "cities", there were regular reports of much smaller flocks or even individual pairs setting up a nesting site. The birds do not seem to have formed as vast breeding colonies at the periphery of their range.
Courtship took place at the nesting colony. Unlike other pigeons, courtship took place on a branch or perch. The male, with a flourish of the wings, made a "keck" call while near a female. The male then gripped tightly to the branch and vigorously flapped his wings up and down. When the male was close to the female, he then pressed against her on the perch with his head held high and pointing at her. If receptive, the female pressed back against the male. When ready to mate, the pair preened each other. This was followed by the birds billing, in which the female inserted its bill into and clasped the male's bill, shook for a second, and separated quickly while standing next to each other. The male then scrambled onto the female's back and copulated, which was then followed by soft clucking and occasionally more preening. John James Audubon described the courtship of the passenger pigeon as follows:
After observing captive birds, Wallace Craig found that this species did less charging and strutting than other pigeons (as it was awkward on the ground), and thought it probable that no food was transferred during their brief billing (unlike in other pigeons), and he therefore considered Audubon's description partially based on analogy with other pigeons as well as imagination.
Nests were built immediately after pair formation and took two to four days to construct; this process was highly synchronized within a colony. The female chose the nesting site by sitting on it and flicking her wings. The male then carefully selected nesting materials, typically twigs, and handed them to the female over her back. The male then went in search of more nesting material while the female constructed the nest beneath herself. Nests were built between above the ground, though typically above , and were made of 70 to 110 twigs woven together to create a loose, shallow bowl through which the egg could easily be seen. This bowl was then typically lined with finer twigs. The nests were about wide, high, and deep. Though the nest has been described as crude and flimsy compared to those of many other birds, remains of nests could be found at sites where nesting had taken place several years prior. Nearly every tree capable of supporting nests had them, often more than 50 per tree; one hemlock was recorded as holding 317 nests. The nests were placed on strong branches close to the tree trunks. Some accounts state that ground under the nesting area looked as if it had been swept clean, due to all the twigs being collected at the same time, yet this area would also have been covered in dung. As both sexes took care of the nest, the pairs were monogamous
Monogamy ( ) is a relationship of two individuals in which they form a mutual and exclusive intimate partnership. Having only one partner at any one time, whether for life or serial monogamy, contrasts with various forms of non-monogamy (e.g. ...
for the duration of the nesting.
Generally, the eggs were laid during the first two weeks of April across the pigeon's range. Each female laid its egg immediately or almost immediately after the nest was completed; sometimes the pigeon was forced to lay it on the ground if the nest was not complete. The normal clutch size appears to have been a single egg, but there is some uncertainty about this, as two have also been reported from the same nests. Occasionally, a second female laid its egg in another female's nest, resulting in two eggs being present. The egg was white and oval shaped and averaged in size. If the egg was lost, it was possible for the pigeon to lay a replacement egg within a week. A whole colony was known to re-nest after a snowstorm forced them to abandon their original colony. Both parents incubated The egg for 12 to 14 days, with the male incubating it from midmorning to midafternoon and the female incubating it the rest of the time.
Upon hatching, the nestling (or squab) was blind and sparsely covered with yellow, hairlike down. The nestling developed quickly and within 14 days weighed as much as its parents. During this brooding period both parents took care of the nestling, with the male attending in the middle of the day and the female at other times. The nestlings were fed crop milk (a substance similar to curd
Curd is obtained by Denaturation (biochemistry), coagulating milk in a sequential process called curdling. It can be a final dairy product or the first stage in cheesemaking. The coagulation can be caused by adding rennet, a Kefir cheese, ...
, produced in the crops of the parent birds) exclusively for the first days after hatching. Adult food was gradually introduced after three to six days. After 13 to 15 days, the parents fed the nestling for a last time and then abandoned it, leaving the nesting area ''en masse''. The nestling begged in the nest for a day or two, before climbing from the nest and fluttering to the ground, whereafter it moved around, avoided obstacles, and begged for food from nearby adults. It was another three or four days before it fledged. The entire nesting cycle lasted about 30 days. It is unknown whether colonies re-nested after a successful nesting. The passenger pigeon sexually matured during its first year and bred the following spring.
Alfred Russel Wallace
Alfred Russel Wallace (8 January 1823 – 7 November 1913) was an English naturalist, explorer, geographer, anthropologist, biologist and illustrator. He independently conceived the theory of evolution through natural selection; his 1858 pap ...
, in his historic 1858 paper On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection
"On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection" is the title of a journal article, comprising and resulting from the joint presentation of two scientific papers to th ...
, used the passenger pigeon as an example of an immensely successful species despite laying fewer eggs than most other birds:
Predators and parasites
Nesting colonies attracted large numbers of predators, including American mink
The American mink (''Neogale vison'') is a semiaquatic species of Mustelidae, mustelid native to North America, though human introduction has expanded its range to many parts of Europe, Asia, and South America. Because of range expansion, the Am ...
s (''Neogale vison''), long-tailed weasel
The long-tailed weasel (''Neogale frenata''), also known as the bridled weasel, masked ermine, or big stoat, is a species of weasel found in North America, North, Central America, Central, and South America. It is distinct from the Stoat, short-t ...
s (''Neogale frenata''), American marten
The American marten (''Martes americana''), also known as the American pine marten, is a species of North American mammal, a member of the Family (biology), family Mustelidae. The species is sometimes referred to as simply the pine marten. The n ...
s (''Martes americana''), and raccoon
The raccoon ( or , ''Procyon lotor''), sometimes called the North American, northern or common raccoon (also spelled racoon) to distinguish it from Procyonina, other species of raccoon, is a mammal native to North America. It is the largest ...
s (''Procyon lotor'') that preyed on eggs and nestlings, birds of prey
Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...
, such as owl
Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers a ...
s, hawk
Hawks are birds of prey of the family Accipitridae. They are very widely distributed and are found on all continents, except Antarctica.
The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks, and others. This ...
s, and eagle
Eagle is the common name for the golden eagle, bald eagle, and other birds of prey in the family of the Accipitridae. Eagles belong to several groups of Genus, genera, some of which are closely related. True eagles comprise the genus ''Aquila ( ...
s that preyed on nestlings and adults, and wolves
The wolf (''Canis lupus''; : wolves), also known as the grey wolf or gray wolf, is a canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, including the dog and dingo, though gr ...
(''Canis lupus''), foxes (''Urocyon cinereoargenteus'' and ''Vulpes vulpes''), bobcat
The bobcat (''Lynx rufus''), also known as the wildcat, bay lynx, or red lynx, is one of the four extant species within the medium-sized wild cat genus '' Lynx''. Native to North America, it ranges from southern Canada through most of the c ...
s (''Lynx rufus''), American black bear
The American black bear (''Ursus americanus''), or simply black bear, is a species of medium-sized bear which is Endemism, endemic to North America. It is the continent's smallest and most widely distributed bear species. It is an omnivore, with ...
s (''Ursus americanus''), and cougar
The cougar (''Puma concolor'') (, ''Help:Pronunciation respelling key, KOO-gər''), also called puma, mountain lion, catamount and panther is a large small cat native to the Americas. It inhabits North America, North, Central America, Cent ...
s (''Puma concolor'') that preyed on injured adults and fallen nestlings. Hawks of the genus '' Accipiter'' and falcons pursued and preyed upon pigeons in flight, which in turn executed complex aerial maneuvers to avoid them; Cooper's hawk (''Accipiter cooperii'') was known as the "great pigeon hawk" due to its successes, and these hawks allegedly followed migrating passenger pigeons. While many predators were drawn to the flocks, individual pigeons were largely protected due to the sheer size of the flock, and overall little damage could be inflicted on the flock by predation. Despite the number of predators, nesting colonies were so large that they were estimated to have a 90% success rate if not disturbed. After being abandoned and leaving the nest, the very fat juveniles were vulnerable to predators until they were able to fly. The sheer number of juveniles on the ground meant that only a small percentage of them were killed; predator satiation may therefore be one of the reasons for the extremely social habits and communal breeding of the species.
Two parasites have been recorded on passenger pigeons. One species of phtilopterid louse
Louse (: lice) is the common name for any member of the infraorder Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera was previously recognized as an order (biology), order, until a 2021 genetic stud ...
, '' Columbicola extinctus'', was originally thought to have lived on just passenger pigeons and to have become coextinct with them. This was proven inaccurate in 1999 when ''C. extinctus'' was rediscovered living on band-tailed pigeons. This, and the fact that the related louse ''C. angustus'' is mainly found on cuckoo-doves, further supports the relation between these pigeons, as the phylogeny of lice broadly mirrors that of their hosts. Another louse, '' Campanulotes defectus'', was thought to have been unique to the passenger pigeon, but is now believed to have been a case of a contaminated specimen, as the species is considered to be the still-extant '' Campanulotes flavus'' of Australia. There is no record of a wild pigeon dying of either disease or parasites.
Relationship with humans
For fifteen thousand years or more before the arrival of Europeans in the Americas, passenger pigeons and Native Americans coexisted in the forests of what would later become the eastern part of the continental United States. A study published in 2008 found that, throughout most of theHolocene
The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...
, Native American land-use practices greatly influenced forest composition. The regular use of prescribed burn
A controlled burn or prescribed burn (Rx burn) is the practice of intentionally setting a fire to change the assemblage of vegetation and decaying material in a landscape. The purpose could be for forest management, ecological restoration, ...
, the girdling
Girdling, also called ring-barking, is the circumferential removal or injury of the bark (consisting of cork cambium or "phellogen", phloem, cambium and sometimes also the xylem) of a branch or trunk of a woody plant. Girdling prevents th ...
of unwanted trees, and the planting and tending of favored trees suppressed the populations of a number of tree species that did not produce nuts, acorns, or fruit, while increasing the populations of numerous tree species that did. In addition, the burning away of forest-floor litter made these foods easier to find, once they had fallen from the trees. Some have argued that such Native American land-use practices increased the populations of various animal species, including the passenger pigeon, by increasing the food available to them, while elsewhere it has been claimed that, by hunting passenger pigeons and competing with them for some kinds of nuts and acorns, Native Americans suppressed their population size. Genetic research may shed some light on this question. A 2017 study of passenger-pigeon DNA found that the passenger-pigeon population size was stable for 20,000 years prior to its 19th-century decline and subsequent extinction, while a 2016 study of ancient Native American DNA found that the Native American population went through a period of rapid expansion, increasing 60-fold, starting about 13–16 thousand years ago. If both of these studies are correct, then a great change in the size of the Native American population had no apparent impact on the size of the passenger-pigeon population. This suggests that the net effect of Native American activities on passenger-pigeon population size was neutral.
The passenger pigeon played a religious role for some northern Native American tribes. The Wyandot people
The Wyandot people (also Wyandotte, Wendat, Waⁿdát, or Huron) are an Indigenous people of the Northeastern Woodlands of the present-day United States and Canada. Their Wyandot language belongs to the Iroquoian languages, Iroquoian language f ...
(or Huron) believed that every twelve years during the Feast of the Dead, the souls of the dead changed into passenger pigeons, which were then hunted and eaten. Before hunting the juvenile pigeons, the Seneca people made an offering of wampum
Wampum is a traditional shell bead of the Eastern Woodlands tribes of Native Americans. It includes white shell beads hand-fashioned from the North Atlantic channeled whelk shell and white and purple beads made from the quahog or Western ...
and brooches to the old passenger pigeons; these were placed in a small kettle or other receptacle by a smoky fire. The Ho-Chunk
The Ho-Chunk, also known as Hocąk, Hoocągra, or Winnebago are a Siouan languages, Siouan-speaking Native Americans in the United States, Native American people whose historic territory includes parts of Wisconsin, Minnesota, Iowa, and Illinois ...
people considered the passenger pigeon to be the bird of the chief, as they were served whenever the chieftain gave a feast. The Seneca people believed that a white pigeon was the chief of the passenger pigeon colony, and that a Council of Birds decided that the pigeons had to give their bodies to the Seneca because they were the only birds that nested in colonies. The Seneca developed a pigeon dance as a way of showing their gratitude.
French explorer Jacques Cartier
Jacques Cartier (; 31 December 14911 September 1557) was a French maritime explorer from Brittany. Jacques Cartier was the first Europeans, European to describe and map the Gulf of Saint Lawrence and the shores of the Saint Lawrence River, wh ...
was the first European to report on passenger pigeons, during his voyage in 1534. The bird was subsequently observed and noted by historical figures such as Samuel de Champlain
Samuel de Champlain (; 13 August 1574#Fichier]For a detailed analysis of his baptismal record, see #Ritch, RitchThe baptism act does not contain information about the age of Samuel, neither his birth date nor his place of birth. – 25 December ...
and Cotton Mather
Cotton Mather (; February 12, 1663 – February 13, 1728) was a Puritan clergyman and author in colonial New England, who wrote extensively on theological, historical, and scientific subjects. After being educated at Harvard College, he join ...
. Most early accounts dwell on the vast number of pigeons, the resulting darkened skies, and the enormous amount of hunted birds (50,000 birds were reportedly sold at a Boston market in 1771). The early colonists thought that large flights of pigeons would be followed by ill fortune or sickness. When the pigeons wintered outside of their normal range, some believed that they would have "a sickly summer and autumn." In the 18th and 19th centuries, various parts of the pigeon were thought to have medicinal properties. The blood was supposed to be good for eye disorders, the powdered stomach lining was used to treat dysentery
Dysentery ( , ), historically known as the bloody flux, is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications may include dehyd ...
, and the dung was used to treat a variety of ailments, including headaches, stomach pains, and lethargy. Though they did not last as long as the feathers of a goose, the feathers of the passenger pigeon were frequently used for bedding. Pigeon feather beds were so popular that for a time in Saint-Jérôme, Quebec, every dowry included a bed and pillows made of pigeon feathers. In 1822, one family in Chautauqua County, New York
Chautauqua County is the westernmost county in the U.S. state of New York. As of the 2020 census, the population was 127,657. Its county seat is Mayville, and its largest city is Jamestown. Its name is believed to be the lone surviving rem ...
, killed 4,000 pigeons in a day solely for this purpose.
The passenger pigeon was featured in the writings of many significant early naturalists, as well as accompanying illustrations. Mark Catesby's 1731 illustration, the first published depiction of this bird, is somewhat crude, according to some later commentators. The original watercolor that the engraving is based on was bought by the British royal family in 1768, along with the rest of Catesby's watercolors. The naturalists Alexander Wilson and John James Audubon both witnessed large pigeon migrations first hand, and published detailed accounts wherein both attempted to deduce the total number of birds involved. The most famous and often reproduced depiction of the passenger pigeon is Audubon's illustration (handcolored aquatint
Aquatint is an intaglio printmaking technique, a variant of etching that produces areas of tone rather than lines. For this reason it has mostly been used in conjunction with etching, to give both lines and shaded tone. It has also been used ...
) in his book '' The Birds of America'', published between 1827 and 1838. Audubon's image has been praised for its artistic qualities, but criticized for its supposed scientific inaccuracies. As Wallace Craig and R. W. Shufeldt (among others) pointed out, the birds are shown perched and billing one above the other, whereas they would instead have done this side by side, the male would be the one passing food to the female, and the male's tail would not be spread. Craig and Shufeldt instead cited illustrations by American artist Louis Agassiz Fuertes and Japanese artist K. Hayashi as more accurate depictions of the bird. Illustrations of the passenger pigeon were often drawn after stuffed birds, and Charles R. Knight is the only "serious" artist known to have drawn the species from life. He did so on at least two occasions; in 1903 he drew a bird possibly in one of the three aviaries with surviving birds, and some time before 1914, he drew Martha, the last individual, in the Cincinnati Zoo.
The bird has been written about (including in poems, songs, and fiction) and illustrated by many notable writers and artists, and is depicted in art to this day, for example in Walton Ford's 2002 painting ''Falling Bough'', and National Medal of Arts
The National Medal of Arts is an award and title created by the United States Congress in 1984, for the purpose of honoring artists and Patronage, patrons of the arts. A prestigious American honor, it is the highest honor given to artists and ar ...
winner John A. Ruthven's 2014 mural in Cincinnati, which commemorates the 100th anniversary of Martha's death. The "Project Passenger Pigeon" outreach group used the centennial of its extinction to spread awareness about human-induced extinction, and to recognize its relevance in the 21st century. It has been suggested that the passenger pigeon could be used as a "flagship
A flagship is a vessel used by the commanding officer of a group of navy, naval ships, characteristically a flag officer entitled by custom to fly a distinguishing flag. Used more loosely, it is the lead ship in a fleet of vessels, typically ...
" species to spread awareness of other threatened, but less well-known North American birds.
Hunting
The passenger pigeon was an important source of food for the people of North America. Native Americans ate pigeons, and tribes near nesting colonies would sometimes move to live closer to them and eat the juveniles, killing them at night with long poles. Many Native Americans were careful not to disturb the adult pigeons, and instead ate only the juveniles as they were afraid that the adults might desert their nesting grounds; in some tribes, disturbing the adult pigeons was considered a crime. Away from the nests, large nets were used to capture adult pigeons, sometimes up to 800 at a time. Low-flying pigeons could be killed by throwing sticks or stones. At one site in Oklahoma
Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...
, the pigeons leaving their roost every morning flew low enough that the Cherokee
The Cherokee (; , or ) people are one of the Indigenous peoples of the Southeastern Woodlands of the United States. Prior to the 18th century, they were concentrated in their homelands, in towns along river valleys of what is now southwestern ...
could throw clubs into their midst, which caused the lead pigeons to try to turn aside and in the process created a blockade that resulted in a large mass of flying, easily hit pigeons. Among the game birds, passenger pigeons were second only to the wild turkey
The wild turkey (''Meleagris gallopavo'') is an upland game bird native to North America, one of two extant species of Turkey (bird), turkey and the heaviest member of the order Galliformes. It is the ancestor to the domestic turkey (''M. g. dom ...
(''Meleagris gallopavo'') in terms of importance for the Native Americans living in the southeastern United States. The bird's fat was stored, often in large quantities, and used as butter. Archaeological evidence supports the idea that Native Americans ate the pigeons frequently prior to colonization.
What may be the earliest account of Europeans hunting passenger pigeons dates to January 1565, when the French explorer René Laudonnière wrote of killing close to 10,000 of them around Fort Caroline
Fort Caroline was an attempted French colonial settlement in Florida, located on the banks of the St. Johns River in present-day Duval County. It was established under the leadership of René Goulaine de Laudonnière on 22 June 1564, follow ...
in a matter of weeks:
This amounted to about one passenger pigeon per day for each person in the fort.
After European colonization, the passenger pigeon was hunted with more intensive methods than the more sustainable
Sustainability is a social goal for people to co-exist on Earth over a long period of time. Definitions of this term are disputed and have varied with literature, context, and time. Sustainability usually has three dimensions (or pillars): env ...
methods practiced by the natives. Yet it has also been suggested that the species was rare prior to 1492, and that the subsequent increase in their numbers may be due to the decrease in the Native American population (who, as well as hunting the birds, competed with them for mast) caused by European immigration, and the supplementary food (agricultural crops) the immigrants imported (a theory for which Joel Greenberg offered a detailed rebuttal in his book, ''A Feathered River Across the Sky''). The passenger pigeon was of particular value on the frontier, and some settlements counted on its meat to support their population. The flavor of the flesh of passenger pigeons varied depending on how they were prepared. In general, juveniles were thought to taste the best, followed by birds fattened in captivity and birds caught in September and October. It was common practice to fatten trapped pigeons before eating them or storing their bodies for winter. Dead pigeons were commonly stored by salting or pickling
Pickling is the process of food preservation, preserving or extending the shelf life of food by either Anaerobic organism, anaerobic fermentation (food), fermentation in brine or immersion in vinegar. The pickling procedure typically affects t ...
the bodies; other times, only the breasts of the pigeons were kept, in which case they were typically smoked. In the early 19th century, commercial hunters began netting and shooting the birds to sell as food in city markets, and even as pig fodder
Fodder (), also called provender (), is any agriculture, agricultural foodstuff used specifically to feed domesticated livestock, such as cattle, domestic rabbit, rabbits, sheep, horses, chickens and pigs. "Fodder" refers particularly to food ...
. Once pigeon meat became popular, commercial hunting started on a prodigious scale.
Passenger pigeons were shot with such ease that many did not consider them to be a game bird, as an amateur hunter could easily bring down six with one shotgun blast; a particularly good shot with both barrels of a shotgun at a roost could kill 61 birds. The birds were frequently shot either in flight during migration or immediately after, when they commonly perched in dead, exposed trees. Hunters only had to shoot toward the sky without aiming, and many pigeons would be brought down. The pigeons proved difficult to shoot head-on, so hunters typically waited for the flocks to pass overhead before shooting them. Trenches were sometimes dug and filled with grain so that a hunter could shoot the pigeons along this trench. Hunters largely outnumbered trappers, and hunting passenger pigeons was a popular sport for young boys. In 1871, a single seller of ammunition provided three tons of powder and 16 tons (32,000 lb) of shot during a nesting. In the latter half of the 19th century, thousands of passenger pigeons were captured for use in the sports shooting industry. The pigeons were used as living targets in shooting tournaments, such as " trap-shooting", the controlled release of birds from special traps. Competitions could also consist of people standing regularly spaced while trying to shoot down as many birds as possible in a passing flock. The pigeon was considered so numerous that 30,000 birds had to be killed to claim the prize in one competition.
Humans used a wide variety of other methods to capture and kill passenger pigeons. Nets were propped up to allow passenger pigeons entry, and then closed by knocking loose the stick that supported the opening, trapping twenty or more pigeons inside. Tunnel nets were also used to great effect, and one particularly large net was capable of catching 3,500 pigeons at a time. These nets were used by many farmers on their own property as well as by professional trappers. Food would be placed on the ground near the nets to attract the pigeons. Decoy
A decoy (derived from the Dutch ''de'' ''kooi'', literally "the cage" or possibly ''eenden kooi'', " duck cage") is usually a person, device, or event which resembles what an individual or a group might be looking for, but it is only meant to ...
or "stool pigeons" (sometimes blinded by having their eyelids sewn together) were tied to a stool. When a flock of pigeons passed by, a cord would be pulled that made the stool pigeon flutter to the ground, making it seem as if it had found food, and the flock would be lured into the trap. Salt was also frequently used as bait, and many trappers set up near salt springs. At least one trapper used alcohol-soaked grain as bait to intoxicate the birds and make them easier to kill. Another method of capture was to hunt at a nesting colony, particularly during the period of a few days after the adult pigeons abandoned their nestlings, but before the nestlings could fly. Some hunters used sticks to poke the nestlings out of the nest, while others shot the bottom of a nest with a blunt arrow to dislodge the pigeon. Others cut down a nesting tree in such a way that when it fell, it would also hit a second nesting tree and dislodge the pigeons within. In one case, of large trees were speedily cut down to get birds, and such methods were common. A severe method was to set fire to the base of a tree nested with pigeons; the adults would flee and the juveniles would fall to the ground. Sulfur
Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...
was sometimes burned beneath the nesting tree to suffocate the birds, which fell out of the tree in a weakened state.
By the mid-19th century, railroad
Rail transport (also known as train transport) is a means of transport using wheeled vehicles running in railway track, tracks, which usually consist of two parallel steel railway track, rails. Rail transport is one of the two primary means of ...
s had opened new opportunities for pigeon hunters. While it was once extremely difficult to ship masses of pigeons to eastern cities, railway access permitted pigeon hunting to become commercialized. An extensive telegraph
Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas ...
system was introduced in the 1860s, which improved communication across the United States, making it easier to spread information about the whereabouts of pigeon flocks. After being opened up to the railroads, the town of Plattsburgh, New York
Plattsburgh is a city in and the county seat of Clinton County, New York, United States, situated on the north-western shore of Lake Champlain. The population was 19,841 at the United States Census, 2020, 2020 census. The population of the sur ...
, is estimated to have shipped 1.8 million pigeons to larger cities in 1851 alone at a price of 31 to 56 cents a dozen. By the late 19th century, the trade of passenger pigeons had become commercialized. Large commission houses employed trappers (known as "pigeoners") to follow the flocks of pigeons year-round. A single hunter is reported to have sent three million birds to eastern cities during his career. In 1874, at least 600 people were employed as pigeon trappers, a number which grew to 1,200 by 1881. Pigeons were caught in such numbers that by 1876, shipments of dead pigeons were unable to recoup the costs of the barrels and ice needed to ship them. The price of a barrel full of pigeons dropped to below fifty cents, due to overstocked markets. Passenger pigeons were instead kept alive so their meat would be fresh when killed, and sold once their market value had increased. Thousands of birds were kept in large pens, though the bad conditions led many to die from lack of food and water, and by fretting (gnawing) themselves; many rotted away before they could be sold.
Hunting of passenger pigeons was documented and depicted in contemporaneous newspapers, wherein various trapping methods and uses were featured. The most often reproduced of these illustrations was captioned "Winter sports in northern Louisiana: shooting wild pigeons", and published in 1875. Passenger pigeons were also seen as agricultural pests
A pest is any organism harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environment fo ...
, because feeding flocks could destroy entire crops. The bird was described as a "perfect scourge" by some farming communities, and hunters were employed to "wage warfare" on the birds to save grain, as shown in another newspaper illustration from 1867 captioned as "Shooting wild pigeons in Iowa". When comparing these "pests" to the bison
A bison (: bison) is a large bovine in the genus ''Bison'' (from Greek, meaning 'wild ox') within the tribe Bovini. Two extant taxon, extant and numerous extinction, extinct species are recognised.
Of the two surviving species, the American ...
of the Great Plains, the valuable resource needed was not the species of animals but the agriculture which was consumed by said animal. The crops that were eaten were seen as marketable calories, proteins, and nutrients all grown for the wrong species.
Decline and conservation attempts
The notion that the species could be driven toextinction
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
was alien to the early colonists, because the number of birds did not appear to diminish, and also because the concept of extinction was yet to be defined. The bird seems to have been slowly pushed westward after the arrival of Europeans, becoming scarce or absent in the east, though there were still millions of birds in the 1850s. The population must have been decreasing in numbers for many years, though this went unnoticed due to the apparent vast number of birds, which clouded their decline. In 1856 Bénédict Henry Révoil may have been one of the first writers to voice concern about the fate of the passenger pigeon, after witnessing a hunt in 1847:
By the 1870s, the decrease in birds was noticeable, especially after the last large-scale nestings and subsequent slaughters of millions of birds in 1874 and 1878. By this time, large nestings only took place in the north, around the Great Lakes. The last large nesting was in Petoskey, Michigan
Petoskey ( ) is the largest city in and the county seat of Emmet County, Michigan, and is the largest settlement within the county. Petoskey has a population of 5,877 at the 2020 census, up from 5,670 at the 2010 census.
Petoskey is part of N ...
, in 1878 (following one in Pennsylvania a few days earlier), where 50,000 birds were killed each day for nearly five months. The surviving adults attempted a second nesting at new sites, but were killed by professional hunters before they had a chance to raise any young. Scattered nestings were reported into the 1880s, but the birds were now wary, and commonly abandoned their nests if persecuted.
By the time of these last nestings, laws had already been enacted to protect the passenger pigeon, but these proved ineffective, as they were unclearly framed and hard to enforce. H. B. Roney, who witnessed the Petoskey slaughter, led campaigns to protect the pigeon, but was met with resistance, and accusations that he was exaggerating the severity of the situation. Few offenders were prosecuted, mainly some poor trappers, but the large enterprises were not affected. In 1857, a bill was brought forth to the Ohio State Legislature seeking protection for the passenger pigeon, yet a Select Committee of the Senate filed a report stating that the bird did not need protection, being "wonderfully prolific", and dismissing the suggestion that the species could be destroyed. Public protests against trap-shooting erupted in the 1870s, as the birds were badly treated before and after such contests. Conservationists were ineffective in stopping the slaughter. A bill was passed in the Michigan legislature making it illegal to net pigeons within of a nesting area. In 1897, a bill was introduced in the Michigan legislature asking for a 10-year closed season on passenger pigeons. Similar legal measures were passed and then disregarded in Pennsylvania. The gestures proved futile and, by the mid-1890s, the passenger pigeon had almost completely disappeared, and was probably extinct as a breeding bird in the wild. Small flocks are known to have existed at this point, since large numbers of birds were still being sold at markets. Thereafter, only small groups or individual birds were reported, many of which were shot on sight.
Last survivors
The last recorded nest and egg in the wild were collected in 1895 near Minneapolis. The last wild individual in Louisiana was discovered among a flock of mourning doves in 1896, and subsequently shot. Many late sightings are thought to be false or due to confusion with mourning doves. The last fully authenticated record of a wild passenger pigeon was near Oakford, Illinois, on March 12, 1901, when a male bird was killed, stuffed, and placed inMillikin University
Millikin University is a private university in Decatur, Illinois, United States. It was founded in 1901 by prominent Decatur businessman James Millikin and is affiliated with the Presbyterian Church (USA).
History
Millikin was initially esta ...
in Decatur, Illinois
Decatur ( ) is the largest city in Macon County, Illinois, United States, and its county seat. The city was founded in 1829 and is situated along the Sangamon River and Lake Decatur in Central Illinois. As of the 2020 United States census, 2020 ...
, where it remains today. This was not discovered until 2014, when writer Joel Greenberg found out the date of the bird's shooting while doing research for his book ''A Feathered River Across the Sky.'' Greenberg also pointed out a record of a male shot near Laurel, Indiana, on April 3, 1902, that was stuffed but later destroyed.
For many years, the last confirmed wild passenger pigeon was thought to have been shot near Sargents, Pike County, Ohio on March 24, 1900, when a boy named Press Clay Southworth killed a female bird with a BB gun
A BB gun is a type of air gun designed to shoot metallic spherical projectiles called BBs (not to be confused with similar-looking bearing balls), which are approximately the same size as BB-size lead birdshot used in shotguns ( in diameter) ...
. The boy did not recognize the bird as a passenger pigeon, but his parents identified it, and sent it to a taxidermist. The specimen, nicknamed "Buttons" due to the buttons used instead of glass eyes, was donated to the Ohio Historical Society
Ohio History Connection, formerly The Ohio State Archaeological and Historical Society and Ohio Historical Society, is a nonprofit organization incorporated in 1885. Headquartered at the Ohio History Center in Columbus, Ohio, Ohio History Connect ...
by the family in 1915. The reliability of accounts after the Ohio, Illinois, and Indiana birds are in question. Ornithologist Alexander Wetmore
Frank Alexander Wetmore (June 18, 1886 – December 7, 1978) was an American ornithologist and avian paleontologist. He was the sixth Secretary of the Smithsonian Institution. He was also an elected member of both the American Philosophical Soc ...
claimed that he saw a pair flying near Independence, Kansas
Independence is a city in and the county seat of Montgomery County, Kansas, Montgomery County, Kansas, United States. As of the 2020 United States census, 2020 census, the population of the city was 8,548. It was named in commemoration of the ...
, in April 1905. On May 18, 1907, U.S. President Theodore Roosevelt
Theodore Roosevelt Jr. (October 27, 1858 – January 6, 1919), also known as Teddy or T.R., was the 26th president of the United States, serving from 1901 to 1909. Roosevelt previously was involved in New York (state), New York politics, incl ...
claimed to have seen a "flock of about a dozen two or three times on the wing" while on retreat at his cabin in Pine Knot, Virginia, and that they lit on a dead tree "in such a characteristically pigeon-like attitude"; this sighting was corroborated by a local gentleman whom he had "rambled around with in the woods a good deal" and whom he found to be "a singularly close observer." In 1910, the American Ornithologists' Union
The American Ornithological Society (AOS) is an ornithological organization based in the United States. The society was formed in October 2016 by the merger of the American Ornithologists' Union (AOU) and the Cooper Ornithological Society. Its ...
offered a reward of $3,000 for discovering a nest— .
Most captive passenger pigeons were kept for exploitative purposes, but some were housed in zoos and aviaries. Audubon alone claimed to have brought 350 birds to England in 1830, distributing them among various noblemen, and the species is also known to have been kept at London Zoo
London Zoo, previously known as ZSL London Zoo or London Zoological Gardens and sometimes called Regent's Park Zoo, is the world's oldest scientific zoo. It was opened in London on 27 April 1828 and was originally intended to be used as a colle ...
. Being common birds, these attracted little interest, until the species became rare in the 1890s. By the turn of the 20th century, the last known captive passenger pigeons were divided in three groups; one in Milwaukee, one in Chicago, and one in Cincinnati. There are claims of a few further individuals having been kept in various places, but these accounts are not considered reliable today. The Milwaukee group was kept by David Whittaker, who began his collection in 1888, and possessed fifteen birds some years later, all descended from a single pair.
The Chicago group was kept by Charles Otis Whitman, whose collection began with passenger pigeons bought from Whittaker beginning in 1896. He had an interest in studying pigeons, and kept his passenger pigeons with other pigeon species. Whitman brought his pigeons with him from Chicago to Massachusetts by railcar each summer. By 1897, Whitman had bought all of Whittaker's birds, and upon reaching a maximum of 19 individuals, he gave seven back to Whittaker in 1898. Around this time, a series of photographs were taken of these birds; 24 of the photos survive. Some of these images have been reproduced in various media, copies of which are now kept at the Wisconsin Historical Society
The Wisconsin Historical Society (officially the State Historical Society of Wisconsin) is simultaneously a state agency and a private membership organization whose purpose is to maintain, promote and spread knowledge relating to the history of ...
. It is unclear exactly where, when, and by whom these photos were taken, but some appear to have been taken in Chicago in 1896, others in Massachusetts in 1898, the latter by a J. G. Hubbard. By 1902, Whitman owned sixteen birds. His pigeons laid many eggs, but few hatched, and many hatchlings died. A newspaper inquiry was published that requested "fresh blood" to the flock which had now ceased breeding. By 1907, he was down to two female passenger pigeons that died that winter, and was left with two infertile male hybrids, whose subsequent fate is unknown. By this time, only four (all males) of the birds Whitman returned to Whittaker were alive, and these died between November 1908 and February 1909.
The Cincinnati Zoo, one of the oldest zoos in the United States, kept passenger pigeons from its beginning in 1875. The zoo kept more than twenty individuals in a cage. Passenger pigeons do not appear to have been kept at the zoo due to their rarity, but to enable guests to have a closer look at a native species. Recognizing the decline of the wild populations, Whitman and the Cincinnati Zoo consistently strove to breed the surviving birds, including attempts at making a rock dove foster passenger pigeon eggs. In 1902, Whitman gave a female passenger pigeon to the zoo; this was possibly the individual later known as Martha, which would become the last living member of the species. Other sources argue that Martha was hatched at the Cincinnati Zoo, lived there for 25 years, and was the descendant of three pairs of passenger pigeons purchased by the zoo in 1877. It is thought this individual was named Martha because her last cage mate was named George, thereby honoring George Washington
George Washington (, 1799) was a Founding Fathers of the United States, Founding Father and the first president of the United States, serving from 1789 to 1797. As commander of the Continental Army, Washington led Patriot (American Revoluti ...
and his wife Martha
Martha (Aramaic language, Aramaic: מָרְתָא) is a Bible, biblical figure described in the Gospels of Gospel of Luke, Luke and Gospel of John, John. Together with her siblings Lazarus of Bethany, Lazarus and Mary of Bethany, she is descr ...
, though it has also been claimed she was named after the mother of a zookeeper's friends.
In 1909, Martha and her two male companions at the Cincinnati Zoo became the only known surviving passenger pigeons. One of these males died around April that year, followed by George, the remaining male, on July 10, 1910. It is unknown whether the remains of George were preserved. Martha soon became a celebrity due to her status as an endling
An endling is the last known individual of a species or subspecies. Once the endling dies, the species becomes extinct. The word was coined in correspondence in the scientific journal ''Nature''.
Usage
The 4 April 1996 issue of ''Nature'' p ...
, and offers of a $1,000 reward () for finding a mate for her brought even more visitors to see her. During her last four years in solitude (her cage was ), Martha became steadily slower and more immobile; visitors would throw sand at her to make her move, and her cage was roped off in response. Martha died of old age on September 1, 1914, and was found lifeless on the floor of her cage. It was claimed that she died at 1 p.m., but other sources suggest she died some hours later. Depending on the source, Martha was between 17 and 29 years old at the time of her death, although 29 is the generally accepted figure. At the time, it was suggested that Martha might have died from an apoplectic stroke, as she had suffered one a few weeks before dying. Her body was frozen into a block of ice and sent to the Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums, Education center, education and Research institute, research centers, created by the Federal government of the United States, U.S. government "for the increase a ...
in Washington, where it was skinned, dissected, photographed, and mounted. As she was molting when she died, she proved difficult to stuff, and previously shed feathers were added to the skin. Martha was on display for many years, but after a period in the museum vaults, she was put back on display at the Smithsonian's National Museum of Natural History
The National Museum of Natural History (NMNH) is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. With 4.4 ...
in 2015. A memorial statue of Martha stands on the grounds of the Cincinnati Zoo, in front of the "Passenger Pigeon Memorial Hut", formerly the aviary wherein Martha lived, now a National Historic Landmark
A National Historic Landmark (NHL) is a National Register of Historic Places property types, building, district, object, site, or structure that is officially recognized by the Federal government of the United States, United States government f ...
. Incidentally, the last specimen of the extinct Carolina parakeet, named "Incus," died in Martha's cage in 1918; the stuffed remains of that bird are exhibited in the "Memorial Hut".
Extinction causes
The main reasons for the extinction of the passenger pigeon were the massive scale of hunting, the rapid loss of habitat, and the extremely social lifestyle of the bird, which made it highly vulnerable to the former factors.Deforestation
Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...
was driven by the need to free land for agriculture and expanding towns, but also due to the demand for lumber and fuel. About 728,000 km2 (180 million acres) were cleared for farming between 1850 and 1910. Though there are still large woodland areas in eastern North America, which support a variety of wildlife, it was not enough to support the vast number of passenger pigeons needed to sustain the population. In contrast, very small populations of nearly extinct birds, such as the kākāpō
The kākāpō (; : ; ''Strigops habroptilus''), sometimes known as the owl parrot or owl-faced parrot, is a species of large, nocturnal, ground-dwelling parrot of the superfamily Strigopoidea. It is endemic to New Zealand.
Kākāpō can be u ...
(''Strigops habroptilus'') and the takahē
The South Island takahē (''Porphyrio hochstetteri'') is a Flightless bird, flightless swamphen indigenous to New Zealand and the largest living member of the Rail (bird), rail family. It is often known by the abbreviated name takahē, whic ...
(''Porphyrio hochstetteri''), have been enough to keep those species extant to the present. The combined effects of intense hunting and deforestation has been referred to as a "Blitzkrieg
''Blitzkrieg'(Lightning/Flash Warfare)'' is a word used to describe a combined arms surprise attack, using a rapid, overwhelming force concentration that may consist of armored and motorized or mechanized infantry formations, together with ...
" against the passenger pigeon, and it has been labeled one of the greatest and most senseless human-induced extinctions in history. As the flocks dwindled in size, the passenger pigeon population decreased below the threshold necessary to propagate the species, an example of the Allee effect
The Allee effect is a phenomenon in biology characterized by a correlation between population size or density and the mean individual fitness (biology), fitness (often measured as ''per capita'' population growth rate) of a population or species.
...
.
The 2014 genetic study that found natural fluctuations in population numbers prior to human arrival also concluded that the species routinely recovered from lows in the population, and suggested that one of these lows may have coincided with the intensified hunting by humans in the 1800s, a combination which would have led to the rapid extinction of the species. A similar scenario may also explain the rapid extinction of the Rocky Mountain locust (''Melanoplus spretus'') during the same period. It has also been suggested that after the population was thinned out, it would be harder for few or solitary birds to locate suitable feeding areas. In addition to the birds killed or driven away by hunting during breeding seasons, many nestlings were also orphaned before being able to fend for themselves. Other, less convincing contributing factors have been suggested at times, including mass drownings, Newcastle disease
Virulent Newcastle disease (VND), formerly exotic Newcastle disease, is a contagious viral avian disease affecting many domestic and wild bird species; it is transmissible to humans. Though it can infect humans, most cases are non-symptomati ...
, and migrations to areas outside their original range.
The extinction of the passenger pigeon aroused public interest in the conservation movement
The conservation movement, also known as nature conservation, is a political, environmental, and social movement that seeks to manage and protect natural resources, including animal, fungus, and plant species as well as their habitat for the ...
, and resulted in new laws and practices which prevented many other species from becoming extinct. The rapid decline of the passenger pigeon has influenced later assessment methods of the extinction risk of endangered animal populations. The International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
(IUCN) has used the passenger pigeon as an example in cases where a species was declared "at risk" for extinction even though population numbers are high.
Naturalist Aldo Leopold
Aldo Leopold (January 11, 1887 – April 21, 1948) was an American writer, Philosophy, philosopher, Natural history, naturalist, scientist, Ecology, ecologist, forester, Conservation biology, conservationist, and environmentalist. He was a profes ...
paid tribute to the vanished species in a monument dedication held by the Wisconsin Society for Ornithology at Wyalusing State Park, Wisconsin
Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...
, which had been one of the species' social roost sites. Speaking on May 11, 1947, Leopold remarked:
Potential resurrection of the species
Today, at least 1,532 passenger pigeon skins (along with 16 skeletons) still exist, spread across many institutions all over the world. It has been suggested that the passenger pigeon should be revived when available technology allows it (a concept which has been termed "de-extinction
De-extinction (also known as resurrection biology, or species revivalism) is the process of generating an organism that either resembles or is an Extinction, extinct organism. There are several ways to carry out the process of de-extinction. Cloni ...
"), using genetic material from such specimens. In 2003, the Pyrenean ibex (''Capra pyrenaica pyrenaica'', a subspecies of the Iberian ibex) was the first extinct animal to be cloned back to life; the clone lived for only seven minutes before dying of lung defects. A hindrance to cloning the passenger pigeon is the fact that the DNA of museum specimens has been contaminated and fragmented, due to exposure to heat and oxygen. American geneticist George M. Church has proposed that the passenger pigeon genome can be reconstructed by piecing together DNA fragments from different specimens. The next step would be to splice these genes into the stem cell
In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can change into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type of cell ...
s of rock pigeons (or band-tailed pigeons), which would then be transformed into egg and sperm cells, and placed into the eggs of rock pigeons, resulting in rock pigeons bearing passenger pigeon sperm and eggs. The offspring of these would have passenger pigeon traits, and would be further bred to favor unique features of the extinct species. The American non-profit organization Revive & Restore is currently pursuing the idea.
The general idea of re-creating extinct species has been criticized, since the large funds needed could be spent on conserving currently threatened species and habitats, and because conservation efforts might be viewed as less urgent. In the case of the passenger pigeon, since it was very social, it is unlikely that enough birds could be created for revival to be successful, and it is unclear whether there is enough appropriate habitat left for its reintroduction. Furthermore, the parent pigeons that would raise the cloned passenger pigeons would belong to a different species, with a different way of rearing young.
Bibliography
Notes
References
External links
Project Passenger Pigeon: Lessons from the Past for a Sustainable Future
The Demise of the Passenger Pigeon
(as broadcast on
National Public Radio
National Public Radio (NPR) is an American public broadcasting organization headquartered in Washington, D.C., with its NPR West headquarters in Culver City, California. It serves as a national Radio syndication, syndicator to a network of more ...
's '' Day to Day'')
360-degree view of Martha, the last passenger pigeon
(
Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums, Education center, education and Research institute, research centers, created by the Federal government of the United States, U.S. government "for the increase a ...
)
{{Authority control
1914 endings
1914 in the environment
Articles containing video clips
Bird extinctions since 1500
passenger pigeon
The passenger pigeon or wild pigeon (''Ectopistes migratorius'') is an bird extinction, extinct species of Columbidae, pigeon that was endemic to North America. Its common name is derived from the French word ''passager'', meaning "passing by" ...
Columbidae
Extinct animals of Canada
Extinct animals of the United States
Extinct birds of North America
Game birds
Historical foods in American cuisine
Native birds of the Eastern United States
Pleistocene first appearances
Species made extinct by human activities
Species that are or were threatened by deforestation
Species that are or were threatened by use as food
passenger pigeon
The passenger pigeon or wild pigeon (''Ectopistes migratorius'') is an bird extinction, extinct species of Columbidae, pigeon that was endemic to North America. Its common name is derived from the French word ''passager'', meaning "passing by" ...