Passenger pigeon
The passenger pigeon or wild pigeon is an extinct species of pigeon that was endemic to North America. 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 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 in size and coloration. The male was in length, mainly gray on the upperparts, lighter on the underparts, with iridescent 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 of eastern North America and was also recorded elsewhere, but bred primarily around the Great Lakes. 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 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, which destroyed its habitat. 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, 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 coined the binomial name Columba macroura for both the mourning dove and the passenger pigeon in the 1758 edition of his work Systema Naturae, 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'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 in 1760. Brisson's description was later shown to have been based on a female passenger pigeon.
In 1827, William Swainson moved the passenger pigeon from the genus Columba to the new monotypic genus Ectopistes, due in part to the length of the wings and the wedge shape of the tail. In 1906 Outram Bangs 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 it appeared on an earlier page in Linnaeus' book. In 1952 Francis Hemming proposed that the International Commission on Zoological Nomenclature 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. The oldest known fossil of the genus is an isolated humerus known from the Lee Creek Mine in North Carolina in sediments belonging to the Yorktown Formation, dating to the Zanclean stage of the Pliocene, between 5.3 and 3.6 million years ago. Its closest living relatives were long thought to be the Zenaida doves, based on morphological grounds, particularly the physically similar mourning dove. 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 sexually dimorphic, and having iridescent neck feathers and a smaller clutch. In a 2002 study by American geneticist Beth Shapiro et al., museum specimens of the passenger pigeon were included in an ancient DNA analysis for the first time, and it was found to be the sister taxon 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 of western North America, which are related to the Southeast Asian species in the genera Turacoena, Macropygia, and Reinwardtoena. This clade is also related to the Columba and Streptopelia doves of the Old World. 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, or perhaps across Beringia in the north.
In a 2012 study, the nuclear DNA 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 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 in the aviary of Charles Otis Whitman 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 passager, which means "to pass by" in a fleeting manner. While the pigeon was extant, the name "passenger pigeon" was used interchangeably with "wild pigeon". 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 in New France, 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 pigeon was called amimi by the Lenape, omiimii by the Ojibwe, and mimia by the Kaskaskia Illinois. Other names in indigenous American languages include ori'te in Mohawk, and putchee nashoba, or "lost dove", in Choctaw. The Seneca people called the pigeon jahgowa, meaning "big bread", as it was a source of food for their tribes. Chief Simon Pokagon of the Potawatomi stated that his people called the pigeon O-me-me-wog, 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 was sexually dimorphic 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, 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-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 scapulars, and the feathers on the sides of the neck had less iridescence 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 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, 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. It is a washed brown on the upper parts, wing covert, secondary feathers, and tail, 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 is a result of a reduction in eumelanin, due to incomplete synthesis of this pigment. 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 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, 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. The coracoid bone 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 end was enlarged. The sternum was very large and robust compared to that of other pigeons; its keel was deep. The overlapping uncinate processes, which stiffen the ribcage, were very well developed. The wing bones were short but robust compared to other pigeons. The leg bones were similar to those of other pigeons.