Pigeon Fledgling

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 short necks and short slender bills that in some species feature fleshy ceres. They primarily feed on seeds, fruits, and plants. The family occurs worldwide, but the greatest variety is in the Indomalayan and Australasian realms.

The family contains 344 species divided into 50 genera. Thirteen of the species are extinct.

In English, the smaller species tend to be called "doves" and the larger ones "pigeons". However, the distinction is not consistent, and does not exist in most other languages. Historically, the common names for these birds involve a great deal of variation between the terms. The bird most commonly referred to as just "pigeon" is the domestic pigeon, which is common in many cities as the feral pigeon.

Doves and pigeons build relatively flimsy nests, often using sticks and other debris, which may be placed on branches of trees, on ledges, or on the ground, depending on species. They lay one or (usually) two white eggs at a time, and both parents care for the young, which leave the nest after 25–32 days. Unfledged baby doves and pigeons are called squabs and are generally able to fly by 5 weeks of age. These fledglings, with their immature squeaking voices, are called squeakers once they are weaned or weaning. Unlike most birds, both sexes of doves and pigeons produce "crop milk" to feed to their young, secreted by a sloughing of fluid-filled cells from the lining of the crop.

Etymology

is a French word that derives from the Latin , for a "peeping" chick, while ''dove'' is an ultimately Germanic word that refers to the bird's diving flight. The English dialectal word appears to derive from Latin . A group of doves is called a "dule", taken from the French word ('mourning').

Origin and evolution

Columbiformes is one of the most diverse non-passerine clades of neoavians, and its origins are in the Cretaceous and the result of a rapid diversification at the end of the K-Pg boundary. Whole genome analyses have found the columbiformes form a sister clade of a group conformed by the sandgrouses (Pterocliformes) and mesites ( Mesitornithiformes).

Taxonomy and systematics

The name 'Columbidae' for the family was introduced by the English zoologist William Elford Leach in a guide to the contents of the British Museum published in 1820. Columbidae is the only living family in the order Columbiformes. The sandgrouse (Pteroclidae) were formerly placed here, but were moved to a separate order, Pterocliformes, based on anatomical differences (such as the inability to drink by "sucking" or "pumping").

The Columbidae are usually divided into five subfamilies, probably inaccurately. For example, the American ground and quail doves (''Geotrygon''), which are usually placed in the Columbinae, seem to be two distinct subfamilies. The order presented here follows Baptista etal. (1997), with some updates.Supplementary information
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The arrangement of genera and naming of subfamilies is in some cases provisional because analyses of different DNA sequences yield results that differ, often radically, in the placement of certain (mainly Indo-Australian) genera. This ambiguity, probably caused by long branch attraction, seems to confirm the first pigeons evolved in the Australasian region, and that the " Treronidae" and allied forms (crowned and pheasant pigeons, for example) represent the earliest radiation of the group.

The family Columbidae previously also contained the family Raphidae, consisting of the extinct Rodrigues solitaire and the dodo. These species are in all likelihood part of the Indo-Australian radiation that produced the three small subfamilies mentioned above, with the fruit doves and pigeons (including the Nicobar pigeon). Therefore, they are here included as a subfamily Raphinae, pending better material evidence of their exact relationships.

Exacerbating these issues, columbids are not well represented in the fossil record. No truly primitive forms have been found to date. The genus ''Gerandia'' has been described from Early Miocene deposits in France, but while it was long believed to be a pigeon, it is now considered a sandgrouse. Fragmentary remains of a probably " ptilinopine" Early Miocene pigeon were found in the Bannockburn Formation of New Zealand and described as '' Rupephaps''; ''"Columbina" prattae'' from roughly contemporary deposits of Florida is nowadays tentatively separated in '' Arenicolumba'', but its distinction from ''Columbina/Scardafella'' and related genera needs to be more firmly established (e.g. by cladistic analysis). Apart from that, all other fossils belong to extant genera.

List of genera

Fossil species of uncertain placement:
* Genus †'' Arenicolumba'' Steadman, 2008
* Genus †'' Rupephaps'' Worthy, Hand, Worthy, Tennyson, & Scofield, 2009 (St. Bathans pigeon, Miocene of New Zealand)

Subfamily Columbinae (typical pigeons and doves)

* Tribe Zenaidini eptotilinae(quail-doves and allies)
** Genus ''Geotrygon'' (10 species)
** Genus '' Starnoenas'' (blue-headed quail-dove)
** Genus '' Leptotrygon'' ( olive-backed quail-dove)
** Genus '' Leptotila'' (11 species)
** Genus '' Zenaida'' (7 species)
** Genus '' Zentrygon'' (8 species)
* Tribe Columbini
** Genus '' Patagioenas'' (American pigeons, 17 species)
** Genus †'' Ectopistes'' (passenger pigeon; extinct 1914)
** Genus '' Reinwardtoena'' (3 species)
** Genus '' Turacoena'' (3 species)
** Genus '' Macropygia'' (typical cuckoo-doves, 15 species)
** Genus ''Streptopelia'' (turtle doves and collared doves, 13 species)
** Genus †'' Dysmoropelia'' Olson, 1975 ( Saint Helena dove) (prehistoric)
** Genus ''Columba'' (Old World pigeons, 35 species of which 2 recently extinct)
** Genus '' Spilopelia'' (2 species)
** Genus '' Nesoenas'' (3 species)

Subfamily Claravinae (American ground doves)

* Genus '' Claravis'' (blue ground dove)
* Genus '' Paraclaravis'' (2 species)
* Genus '' Uropelia'' ( long-tailed ground dove)
* Genus '' Metriopelia'' (4 species)
* Genus ''Columbina'' (9 species)

Raphinae

* Tribe Phabini (bronzewings and relatives)
** Genus ''Henicophaps'' (2 species)
** Genus '' Gallicolumba'' (bleeding-hearts and allies, 7 species)
** Genus '' Pampusana'' (13 species of which 3 recently extinct)
** Genus ''Ocyphaps'' (crested pigeon)
** Genus '' Petrophassa'' (rock pigeons, 2 species)
** Genus '' Leucosarcia'' (wonga pigeon)
** Genus '' Geopelia'' (5 species)
** Genus ''Phaps'' (Australian bronzewings, 3 species)
** Genus ''Geophaps'' (3 species)
* Tribe Raphini idunculinae; Otidiphabinae; Gourinae** Genus ?†'' Natunaornis'' ( Viti Levu giant pigeon) (prehistoric)
** Genus '' Trugon'' ( thick-billed ground pigeon)
** Genus †'' Microgoura'' ( Choiseul crested pigeon, extinct early 20th century)
** Genus ''Otidiphaps'' ( pheasant pigeon)
** Genus '' Goura'' (crowned pigeons, 4 species)
** Genus '' Didunculus'' (tooth-billed pigeon)
** Genus ?†'' Deliaphaps'' De Pietri, Scofield, Tennyson, Hand, & Worthy, 2017 (Zealandian dove, Miocene of New Zealand)
** Genus '' Caloenas'' (Nicobar pigeon)
** Genus †'' Raphus'' (dodo, extinct late 17th century)
** Genus †'' Pezophaps'' (Rodrigues solitaire, extinct c. 1730)
** Genus †'' Bountyphaps'' Worthy & Wragg, 2008 (Henderson Island pigeon) (prehistoric)
* Tribe Turturini
** Genus '' Phapitreron'' (brown doves, 3 species)
** Genus ''Oena'' (Namaqua dove, tentatively placed here)
** Genus '' Turtur'' (wood doves, 5 species; tentatively placed here)
** Genus '' Chalcophaps'' (emerald doves, 3 species)
* Tribe Treronini
** Genus ''Treron'' ( green pigeons, 30 species)
* Tribe Ptilinopini (fruit doves and imperial pigeons)
** Genus '' Ducula'' (imperial pigeons, 36 species)
** Genus ''Ptilinopus'' 'Drepanoptila''; ''Alectroenas">Drepanoptila.html" ;"title="'Drepanoptila">'Drepanoptila''; ''Alectroenas''] (fruit doves, some 50 living species, 1–2 recently extinct)
** Genus ''Hemiphaga'' (2 species)
** Genus '' Lopholaimus'' (topknot pigeon)
** Genus '' Cryptophaps'' (sombre pigeon)
** Genus '' Gymnophaps'' (mountain pigeons, 4 species)
** Genus ?†'' Tongoenas'' Steadman & Takano, 2020 (Tongan giant pigeon) (prehistoric)

Description

Size and appearance

Pigeons and doves exhibit considerable variation in size, ranging in length from , and in weight from to above . The largest species is the crowned pigeon of New Guinea, which is nearly turkey-sized, at a weight of . The smallest is the New World ground dove of the genus ''Columbina'', which is the same size as a house sparrow, weighing as little as . The dwarf fruit dove, which may measure as little as , has a marginally smaller total length than any other species from this family. One of the largest arboreal species, the Marquesan imperial pigeon, currently battles extinction.

Anatomy and physiology

Overall, the anatomy of Columbidae is characterized by short legs, short bills with a fleshy cere, and small heads on large, compact bodies. Like some other birds, the Columbidae have no gall bladders. Some medieval naturalists concluded they have no bile (gall), which in the medieval theory of the four humours explained the allegedly sweet disposition of doves. In fact, however, they do have bile (as Aristotle had earlier realized), which is secreted directly into the gut.

The wings are large, and have eleven primary feathers; pigeons have strong wing muscles (wing muscles comprise 31–44% of their body weight) and are among the strongest fliers of all birds.

In a series of experiments in 1975 by Dr.Mark B. Friedman, using doves, their characteristic head bobbing was shown to be due to their natural desire to keep their vision constant. It was shown yet again in a 1978 experiment by Dr.Barrie J. Frost, in which pigeons were placed on treadmills; it was observed that they did not bob their heads, as their surroundings were constant.

Feathers

Columbidae have unique body feathers, with the shaft being generally broad, strong, and flattened, tapering to a fine point, abruptly. In general, the aftershaft is absent; however, small ones on some tail and wing feathers may be present. Body feathers have very dense, fluffy bases, are attached loosely into the skin, and drop out easily. Possibly serving as a predator avoidance mechanism, large numbers of feathers fall out in the attacker's mouth if the bird is snatched, facilitating the bird's escape. The plumage of the family is variable. Granivorous species tend to have dull plumage, with a few exceptions, whereas the frugivorous species have brightly coloured plumage. The ''Ptilinopus'' (fruit doves) are some of the brightest coloured pigeons, with the three endemic species of Fiji and the Indian Ocean ''Alectroenas'' being the brightest. Pigeons and doves may be sexually monochromatic or dichromatic. In addition to bright colours, pigeons may sport crests or other ornamentation.

Flight

Columbidae are excellent fliers due to the lift provided by their large wings, which results in low wing loading; They are highly maneuverable in flight and have a low aspect ratio due to the width of their wings, allowing for quick flight launches and ability to escape from predators, but at a high energy cost.

Distribution and habitat

Pigeons and doves are distributed everywhere on Earth, except for the driest areas of the Sahara Desert, Antarctica and its surrounding islands, and the high Arctic. They have colonised most of the world's oceanic islands, reaching eastern Polynesia and the Chatham Islands in the Pacific, Mauritius, the Seychelles and Réunion in the Indian Ocean, and the Azores in the Atlantic Ocean.

The family has adapted to most of the habitats available on the planet. These species may be arboreal, terrestrial, or semi-terrestrial. Various species also inhabit savanna, grassland, desert, temperate woodland and forest, mangrove forest, and even the barren sands and gravels of atolls.

Some species have large natural ranges. The eared dove ranges across the entirety of South America from Colombia to Tierra del Fuego, the Eurasian collared dove has a massive (if discontinuous) distribution from Britain across Europe, the Middle East, India, Pakistan and China, and the laughing dove across most of sub-Saharan Africa, as well as India, Pakistan, and the Middle East. Other species have tiny, restricted distributions; this is most common in island endemics. The whistling dove is endemic to the tiny Kadavu Island in Fiji, the Caroline ground dove is restricted to two islands, Truk and Pohnpei in the Caroline Islands, and the Grenada dove is restricted to Grenada in the Caribbean. Some continental species also have tiny distributions; for example, the black-banded fruit dove is restricted to a small area of the Arnhem Land of Australia, the Somali pigeon is restricted to a tiny area of northern Somalia, and Moreno's ground dove is restricted to the area around Salta and Tucuman in northern Argentina.

The largest range of any species is that of the rock dove. This species had a large natural distribution from Britain and Ireland to northern Africa, across Europe, Arabia, C