Mesopotamian cuneiform tablets mention the domestication of pigeons more than 5,000 years ago, as do Egyptian hieroglyphics.

Despite this, city pigeons, which are feral birds, are generally seen as pests, mainly due to their droppings and a reputation for spreading disease.

Their fragile bones and similarity to wild birds make the fossil record a poor tool for their study.

[13] Although other sources cite Plymouth and Jamestown settlements in the early 17th century as the first place for species introduction in North America.

[15] A wild-type pigeon is closest in markings to the rock dove, which possesses a gradienting, slate-grey head and body with a green-purple iridescent neck, and ash-grey wings and tail with dark, often black, barring.

Due to millennia of selective breeding, including crossing with other Columba species, domestic pigeons possess major variations in plumage; often two birds from the same clutch may be of different color.

[17] Another important aspect of pigeon markings is the pattern on the wing coverts, which exists in four variants; wild-type bar, check, T-check, and barless.

A pigeon keeper may select breeding partners, but in an open loft the birds choose their own mate.

Both sexes of pigeons are extremely protective of their eggs and young, and often defend them vigorously from nest predators, including their human keepers.

[citation needed] Domestic pigeons were selected to breed faster than their wild ancestors;[38] a lack of a breeding season, abundance of food in a domestic setting, and swift maturity (squabs fledge in about a month, and often have already bred and fledged a few clutches of their own before reaching a year in age) leads to swift population growth of pigeons in the flock.

This fact, and the number of pigeons lost in races or intentionally released, leads to exponential growth in free-living, feral populations.

A form of hypersensitivity pneumonitis, pigeon lung is caused by the inhalation of the avian proteins found in feathers and dung.

There are several methods to treat birds infested with mites or louse, including external insecticides and oral medicine.

Squabs during this stage are valued as food; in neolithic and early agricultural communities they were an easy and reliable source of protein, the birds requiring only reliable sources of grains and water (which they independently foraged for) to enter breeding condition, and the rock formations they nested in would have made for attractive dwellings for early humans[citation needed].

[41] These breeds of domestic pigeons, especially when trained 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 1,000 km (620 mi) away.

[52] Other potential cues used include Their navigational reliability has led to a historical reliance of the pigeon in long-distance messaging, most notably in wartime.

Fanciers compete against each other at exhibitions or shows and the different forms or breeds are judged to a standard to decide who has the best bird.

Domestic pigeons are model organisms commonly used in laboratory experiments relating to biology; often to test medicines and chemical substances, or in cognitive sciences.

They have been successfully trained under research conditions to examine data on a screen for the purposes of detecting breast cancer.

[69] Domestic pigeons, especially the leucistic and albinistic specimens commonly referred to as "white doves", have had a long history in symbolism.

He would subsequently take on pigeon fancying himself, which would ultimately lead to another book; The Variation of Animals and Plants Under Domestication.

[70] In American pigeon-related organizations, some enthusiasts have openly shared their experiences of killing hawks and falcons, although this is frowned upon by some fanciers.

[citation needed] In the West Midlands region of the United Kingdom pigeon fanciers have been blamed for a trap campaign to kill peregrine falcons.

The steel traps are thought to have been set as part of a "concerted campaign" to kill as many of the birds as possible in the West Midlands.

[7] As a result of inherited genetic variation, feral pigeons demonstrate a wide variety of plumage patterns and colors, ranging from closely resembling wild rock doves, to patterns directly inherited from their domestic ancestors, though over time a population tends to homogenize and adopt a plumage that suits their environment, such as camouflaging against black asphalt.