Field Guide/Birds/Columba livia

The Rock Pigeon (Columba livia), is a member of the bird family Columbidae, doves and pigeons. The bird is also known by the names of feral pigeon or domestic pigeon. In common usage, this bird is often simply referred to as the "pigeon". The species was commonly known as Rock Dove until the British Ornithologists' Union and the American Ornithologists' Union changed the official English name of the bird in their regions to Rock Pigeon.

Habitat

Rock Pigeons in their natural habitat perched on sea cliffs.

The Rock Pigeon has a restricted natural resident range in western and southern Europe, North Africa, and into South Asia. Its habitat is natural cliffs, usually on coasts. Its domesticated form, the feral pigeon, has been widely introduced elsewhere, and is common, especially in cities, over much of the world. In Britain, Ireland, and much of its former range, the Rock Pigeon probably only occurs pure in the most remote areas. A Rock Pigeon's life span is anywhere from 3–5 years in the wild to 15 years in captivity, though longer-lived specimens have been reported. Pigeons are also k/a Kabutar in hindi. (Ashwin Krishnan) The species was first introduced to North America in 1606 at Port Royal, Acadia (now Nova Scotia).

Characteristics

The Rock Pigeon is 30–35 cm long with a 62–68 cm wingspan. The white lower back of the pure Rock Pigeon is its best identification character, but the two black bars on its pale grey wings are also distinctive. The tail is margined with white. It is strong and quick on the wing, dashing out from sea caves, flying low over the water, its white rump showing well from above.

The head and neck of the mature bird are a darker blue-grey than the back and wings; the lower back is white. The green and lilac or purple patch on the side of the neck is larger than that of the Stock Dove, and the tail is more distinctly banded. Young birds show little lustre and are duller. Eye colour of the pigeon is generally an orange colour but a few pigeons may have white-grey eyes. The eyelids are orange in colour and are encapsulated in a grey-white eye ring. Feet are red to pink in color.

Varying eye colour in Rock Pigeons.

When circling overhead, the white under wing of the bird becomes conspicuous. In its flight, behaviour, and voice, which is more of a dovecot coo than the phrase of the Wood Pigeon, it is a typical pigeon. Although it is a relatively strong flier, it also glides frequently, holding its wings in a very pronounced V shape as it does. Though fields are visited for grain and green food, it is nowhere so plentiful as to be a pest.

The bowing courtship, when the metallic lustre of the neck is fully displayed, often takes place on ledges where Guillemots and Razorbills sit.

A small prehistoric subspecies of the Rock Dove that lived during the last ice age in Italy has been described as Columba livia minuta.

Nest and nestling

The nest is usually on a ledge in a cave; it is a slight structure of grass, heather, or seaweed. Like most pigeons it lays two white eggs. The eggs are incubated by both parents for about 18 days.

The nestling has pale yellow down and a flesh-coloured bill with a dark band. It is tended and fed on "crop milk" like other doves. The fledging period is 30 days.

Egg, measured in centimetres
Nest with two eggs
Newly hatched nestling and one egg
Nestlings, one day
Nestling, five days
Nestlings, about ten days
Young bird, 22 days

Domestication

Rock Dove in flight

Rock Pigeons have been domesticated for several thousand years, giving rise to the domestic pigeon. Trained domestic pigeons are able to return to the home loft if released at a location that they have never visited before and that may be up to 1000 km away. A special breed, called homing pigeons has been developed through selective breeding to carry messages and members of this variety of pigeon are still being used in pigeon racing.

Pigeons are also bred for meat and by fanciers to develop many exotic forms. Among those forms are the carrier pigeons, a variety of pigeon with wattles and a unique, almost vertical, stance (pictures). Young pigeon meat is often sold under the name squab.

Pigeons' extraordinary navigation abilities have been attributed to the theory that they are able to sense the Earth's magnetic field with tiny magnetic tissues in their head. This is all the more surprising as they are not a migratory species, which is a fact used by some ornithologists to dispute the "compass pigeon" theory.

Many domestic birds have escaped or been released over the years, and have given rise to the feral pigeon. These show a variety of plumages, although some look very like the pure Rock Pigeons. The scarcity of the pure wild species is due to interbreeding with feral birds.

Many people consider pigeons to be pests but they have made contributions of considerable importance to humanity, especially in times of war. In war the homing ability of pigeons has been put to use by making them messengers. So-called war pigeons have carried many vital messages and some have been decorated for their service. Medals such as the Croix de guerre, awarded to Cher Ami, and the Dickin Medal awarded to G.I. Joe have been given to pigeons for their service.

Feral Rock Pigeons commonly show a very wide range of plumage variation

Domestic pigeons are also commonly used in laboratory experiments in biology, medicine and cognitive science. They have been trained to distinguish between cubist and impressionist paintings, for instance. In another project, pigeons were shown to be more effective than humans in spotting shipwreck victims at sea. Current (2004) research in pigeons is widespread, encompassing shape and texture perception, exemplar and prototype memory, category-based and associative concepts, and many more unlisted here (see Pigeon intelligence and discrimination abilities of pigeons).

Pigeons grow to a very large size in the nest before they are fledged and able to fly, and in this stage of their development (when they are called squabs) they are prized as food. For commercial meat production a breed of large white pigeon, named "King pigeons," has been developed by selective breeding.

There are many ornamental breeds of pigeons, among the most beautiful of which is the "Duchess" breed, which has as a prominent characteristic feet that are completely covered by a sort of fan of feathers. The fantails are also very ornamental with their fan-shaped tail feathers.

Feral pigeons in cities

Although feeding them is now forbidden, pigeons still flock to London's Trafalgar Square

Feral pigeons, also called city doves or city pigeons, find the ledges of high buildings a perfect substitute for sea cliffs, and have become abundant in cities all over the world. However, they are often considered a pest or even vermin, owing to concerns that they spread disease (perhaps unfounded, see 1), damage property, cause pollution with their excrement, and drive out other bird species. Alternative, pejorative, nicknames for pigeons are sky rats, rats with wings, feathered rats or gutter birds. In Montreal, Quebec, Canada, they are also commonly referred to as flying ashtrays.

Many city squares are famous for their large pigeon populations, including:

In the mid 20th century, the pigeons in Trafalgar Square were considered a tourist attraction, with street vendors selling packets of seeds for visitors to feed the pigeons. The feeding of the Trafalgar Square pigeons was controversially forbidden^& in 2003 by London mayor Ken Livingstone. However, activist groups such as Save the Trafalgar Square Pigeons^& flouted the ban, feeding the pigeons from a small part of the square that is under the control of Westminster City Council, not the mayor. The organisation has since come to an agreement to feed the pigeons only once a day, at 7.30am^&.

Many places where pigeons could land are covered with spikes

Although pest exterminators using poison, a hawk or nets have been employed at ground level to control urban pigeon populations, the effect is limited and very short term. Pigeons breed when the food supply is good—for wild rock doves this might be on a seasonal basis so they usually breed once a year. In the urban environment, because of their year-round food supply, feral pigeons will breed continuously, laying eggs up to six times a year.

Feral pigeons can be seen eating grass seeds and berries in urban parks and gardens in the spring, but there are plentiful sources throughout the year from scavenging (e.g. dropped fast-food cartons). Further food is also usually available from the disposing of stale bread in parks by restaurants and supermarkets, from tourists buying and distributing birdseed, etc. Pigeons tend to congregate in large, often thick flocks when going for discarded food, and many have been observed flying skillfully around trees, buildings, telephone poles and cables, and even moving traffic just to reach it.

A Rock Pigeon perched in Central Park

Long term reduction of feral pigeon populations can be achieved by restricting food supply, which in turn will involve legislation and litter (garbage) control. Some cities have deliberately established favorable nesting places for pigeons – nesting places that can easily be reached by city workers who regularly remove eggs, thereby limiting their reproductive success. (See Dove Overpopulation.)

As a result of the continuous food supply, pigeon courtship rituals can be observed in urban parks at any time of the year. Males on the ground initially puff up feathers at the nape of the neck to increase their apparent size and thereby impress or attract attention, then they single out a female in the vicinity and approach at a rapid walk, often bowing as they approach. Females invariably initially walk away or fly short distances, the males follow them at each stage. Persistence by the male will usually eventually cause the female to tolerate his proximity, at which point he will continue the bowing motion and very often turn full- or half-pirouettes in front of the female. Subsequent mating when observed is very brief with the male flapping his wings to maintain balance on the female. Sometimes the male and female beaks are locked together.

Nests are rudimentary as for the wild doves and pigeons. Favourite nesting areas are in damaged property. Mass nesting is common with dozens of birds sharing a building. Loose tiles and broken windows give pigeons access – they are remarkably good at spotting when new access points become available, for example after strong winds cause property damage. Nests and droppings will quickly make a mess of any nesting area. Pigeons are particularly fond of roof spaces containing water tanks, though they frequently seem to fall into the tanks and drown. Any water tank or cistern in a roof space needs to have a secure lid for this reason. The popularity of a nesting area seems little affected if pigeons die or are killed there – corpses are seen among live birds, who seem unconcerned.

On undamaged property the gutters, window air conditioners, chimney pots and external ledges will be used as nesting sites. Many building owners attempt to limit roosting by using bird control spikes and netting to cover ledges and resting places on the facades of buildings. These probably have little effect on the size of pigeon populations, but can help to reduce the accumulation of droppings on and around an individual building.

Only the larger and more wary Wood Pigeon (which often shares the same territory and food supply) will build a tree nest; for some reason it prefers trees close to roads.

The coo-ing of the feral pigeon is almost continuous when birds are on a nest; it is rarely heard at other times except courtship. Males are at least as likely to be on the nest as females, though a pair of birds will attend the nest.

Peregrine Falcons which are also originally cliff dwellers have also adapted to the big cities, living on the window ledges of skyscrapers and often feeding exclusively on Rock Pigeons. Some cities actively encourage this through falcon breeding programs.[1]

Symbolism

A old pigeon-house in Doorn, The Netherlands

White doves, usually meaning domesticated Rock Pigeons, are a traditional Christian and Jewish symbol of love and peace. According to the biblical story, a dove was released by Noah after the flood in order to find land; it came back carrying an olive branch, telling Noah that, somewhere, there was land. A dove with an olive branch has since then come to symbolize peace. In Christian iconography, a dove also symbolizes the Holy Spirit, in reference to Matthew 3:16 and Luke 3:22 where the Holy Spirit appeared as a dove at the Baptism of Jesus.
Doves or other birds are sometimes released at Christian weddings. They are generally the valued property of individuals who provide them specifically for this purpose. They are regularly permitted to fly free from their home dove cotes and therefore know very well how to fly back home after leaving the scene of the marriage ceremony. All rock pigeons are capable of homing over such short distances, but occasionally birds may be distracted by finding a mate or by being caught by a predator.
Doves are often associated with the concept of peace and pacifism. They often appear in political cartoons, on banners and signs at events promoting peace (such as the Olympic games, at various anti-war/anti-violence protests, etc.), and in pacifist literature. A person who is a pacifist is sometimes referred to as a dove (similarly, in American politics, a person who advocates the use of military resources as opposed to diplomacy can be referred to as a hawk).
Rock pigeons selectively bred for their ability to home over long distances, called homing pigeons, have served humans in times of war as war pigeons, and have even been awarded war medals to honour their services to humanity. These include the homing pigeon, Cher Ami, who received the French Croix de guerre for services during wartime, and who is now enshrined in the Smithsonian Institution, and G.I. Joe, who received the Dickin Medal for his role in preventing the bombing of an Italian village of over 1,000 people.

Spread of disease

Though feral pigeons are often associated with the threat of disease, this is actually a fairly recent idea. Brought about and popularized in part by pest control companies in the 1980s, the concept of dangerously communicable diseases spread by these city dwelling birds stands in stark contrast to reality.[2] To quote Dr. Manuel Vargas of the New York City Department of Health: "[We have] no documented cases of communicable disease transmitted from pigeons to humans."[3]

In addition, pigeons do not spread West Nile Virus; though they can contract it, they do not appear to be able to transmit it. In fact, they are no longer monitored as an indication of the presence of the virus in the area (as crows still are.) Pigeons are also at extremely low risk for carrying or even contracting avian flu.[4]

Certainly pigeons, like any other wild animal, carry some risk of disease. They are known, in particular, to be susceptible to salmonellosis, tuberculosis, and ornithosis. (None of these have been proven to be transmitted from pigeons to humans, however.) It is wise, therefore, to use precautions when handling them.

Pigeon Lung

Pigeon breeders sometimes suffer from an ailment known as Pigeon Lung. A form of Hypersensitivity pneumonitis, Pigeon Lung is caused by the inhalation of the avian proteins found in feathers and dung. It can sometimes be combatted by wearing a filtered mask.[5]

Overpopulation

In the last few decades, people have begun to poison feral pigeons when their numbers become too large. This has proven to be fairly ineffective, however, as pigeons can breed very quickly (up to six times a year) and their numbers are determined by how much food is available; that is, they breed more often when more food is provided to them. When pigeons are poisoned, surviving birds do not leave the area. On the contrary, they are left with more food per bird than before. This attracts pigeons from outside areas as well as encouraging more breeding, and populations are re-established quickly.

A more effective tactic to reduce the number of feral pigeons is deprivation. [6], [7] Cities around the world have discovered that not feeding their local birds results in a safe population decrease in only a few years. Pigeons, however, will still pick at garbage bags containing discarded food or at leftovers carelessly dropped on the ground.

References

Template:IUCN2006 Database entry includes justification for why this species is of least concern
Collins Bird Guide by Mullarney, Svensson, Zetterström and Grant ISBN 0-00-219728-6
Template:ITIS

External links

bg:Скален гълъб cs:Holub skalní da:Klippedue de:Felsentaube es:Columba livia eo:Kolombo fr:Pigeon biset lt:Naminis karvelis hu:Házigalamb nl:Rotsduif ja:カワラバト pl:Gołąb skalny pt:Pombo-comum ru:Голубь обыкновенный fi:Kesykyyhky sv:Klippduva tr:Kaya güvercini zh:原鸽

[1] Feeding Trafalgar Square's Pigeons illegal BBC News

[2] Save the Trafalgar Square Pigeons

[3] Save the Trafalgar Square Pigeons - Background

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