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.

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

The Rock Pigeon has a restricted natural resident range in western and southern Europe, North Africa, and into southwest 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, living in any covered space within a building. 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.

The species was first introduced to North America in 1606 at Port Royal, Acadia (now Nova Scotia).

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.

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.

Varying eye colour in Rock Pigeons.

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.

Rock Pigeons in their natural habitat perched on sea cliffs. Most pigeons in an urban environment substitute sheer building facades for cliff faces

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.

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  Egg, measured in centimetres

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  Nest with two eggs

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  Newly hatched nestling and one egg

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  Nestlings, one day

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  Nestling, five days

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  Nestlings, about ten days

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  Young bird, 22 days

Domestication

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.

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).

Feral pigeons in cities

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

File:Pigeon-in-flight-over-asphalt.jpg

Pigeon in flight

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, damage property, cause pollution with their excrement, and drive out other bird species. Alternative, pejorative, nicknames for pigeons are sky rats, rats with wings, 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:

• Trafalgar Square — London
• Dam Square — Amsterdam
• Martin Place — Sydney
• Piazza San Marco — Venice
• Misir Carshisi — Istanbul
• Rynek Główny — Cracow
• Richard J. Daley Center — Chicago
• Piccadilly Gardens — Manchester

Many places where pigeons could land are covered with spikes

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.

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 only be achieved by restricting food supply, which in turn will involve legislation and litter (garbage) control.

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, 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.

See also

• Birdfeeding
• Pigeon Sport
• Tipplers
• Homing pigeons
• Histoplasmosis
• List of Pigeon Breeds

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

• Why do pigeons bob their heads? (from The Straight Dope)
• BBC Life and Nature (from the BBC)
• Facts about pigeon-related diseases