The domestic pigeon (Columba livia "domestica" or Columba livia forma domestica) is a bird that was tamed by humans and comes from the rock dove (Columba livia). While sometimes called a "subspecies," the domestic pigeon is not officially recognized as a subspecies of the rock dove. Instead, it includes more than 350 different breeds. The rock dove is one of the earliest birds to be domesticated. Ancient writings, such as Mesopotamian cuneiform tablets and Egyptian hieroglyphs, describe pigeons being raised by humans over 5,000 years ago.

Pigeons have been important to humans throughout history for food, companionship, symbolism, and communication. Their ability to return to their home location has made them useful for sending messages, including during both world wars when they were used as war pigeons. City pigeons, which are wild birds living in urban areas, are often considered pests because their droppings can cause problems and they are sometimes linked to spreading diseases.

History of domestication

The exact subspecies of C. livia that first became domesticated, when this happened, how many times it occurred, where it took place, and how domestic pigeons spread across the world is not well understood. Although pigeons have a long history, very little is known about the specific details of their earliest domestication. Genetically, domesticated pigeons are most closely related to a group of rock doves found in the Middle East, especially in the Syria–Jordan–Iraq–Arabian Peninsula region, as well as in eastern Sudan. This area includes parts of the natural ranges of C. l. gaddi, C. l. palaestinae, and C. l. butleri.

The fragile bones of pigeons and their similarity to wild birds make it difficult to study them using fossils. Most information about their domestication comes from written records, which likely do not include the earliest stages of this process.

Pigeons were probably domesticated at least 2,000 to 5,000 years ago, possibly even earlier as a food source. Some research suggests domestication may have begun as far back as 10,000 years ago. The earliest written records about pigeons date to around 5,000 years ago in Mesopotamia. In Cappadocia, ancient rock formations were carved into dovecotes. Ancient Egyptians also kept pigeons. Akbar the Great, a historical leader, traveled with thousands of pigeons.

Because domestic and feral pigeons have often mated with wild rock doves, genetically pure wild rock doves are now rare and endangered. These birds are mostly found in remote areas, such as the Outer Hebrides near western Scotland. This frequent mixing of genes makes it harder to determine the true origins of domestic pigeons.

Domestic pigeons were brought to the Americas by European colonists for food and as messengers. Some sources say the first pigeons arrived in North America in 1606 at Port Royal, Nova Scotia, while others mention the Plymouth and Jamestown settlements in the early 1700s as the first locations in North America where pigeons were introduced.

In the 18th century, Europeans became interested in breeding fancy pigeons. Breeders expanded the variety of pigeons by importing birds from the Middle East and South Asia and mixing different breeds. Among these breeders was Charles Darwin, who was asked to write a book on pigeons while working on On the Origin of Species. His experiences with pigeon breeding later inspired another book, The Variation of Animals and Plants Under Domestication.

Genetics

From a genetic perspective, there are two main groups of pigeon ancestors, but their genes are very similar because they often mate with each other and humans have bred them intentionally. Unlike dogs, pigeon breeders usually do not strictly follow breed rules. The first group includes pigeons with large crops, tails, and neck feathers. The second group includes tumblers (the most varied group), homing pigeons, owl pigeons, and pigeons with large wattles. Over thousands of years, humans have created many pigeon breeds that differ in either feather color or body shape.

Some domestic pigeons have special feathers called "fat quills." These feathers contain yellow, oily fat that comes from the same cells as powder down. This oil helps protect feathers from bacteria during preening.

A "wild-type" pigeon looks most like the rock dove. It has a gray head and body, a green-purple shiny neck, and dark, black-streaked wings and tail. It also has a thicker beak, a larger bump at the base of the beak, a flatter head shape, and a lighter ring around its eyes. Because of long-term human breeding, including mixing with other pigeon species, domestic pigeons have many differences in feather color. Often, two pigeons from the same nest may have different colors. Domestic pigeons have three main colors: wild-type blue, brown, and ash-red. These color differences are linked to the parents’ sex chromosomes. Since pigeons have a ZW chromosome system, male pigeons get color genes from both parents, while females only get their father’s color and patterns. Some colors are more dominant: ash-red is dominant over blue and brown, and blue is dominant over brown. A unique color called "recessive red" is always a solid chestnut color and is inherited differently from the other colors.

Another key feature is the pattern on the wing feathers, which has four types: wild-type bar, check, T-check, and barless. T-check is the most common pattern, followed by check, bar, and barless (the least common). Two other genes, "spread" and "dilute," affect how colors appear. The spread gene makes the tail color cover the whole body, while the dilute gene lightens the bird’s overall color.

Other markings include milky, almond, opal, dirty, indigo, grizzle, and patterns like "stencil" and "bronzing," which further change a bird’s base color. Pigeons can also have multiple genetic ways to become completely white.

A recessive gene in the EphB2 gene causes the crested-feather trait. Pigeons with two copies of this gene grow feathers on their heads and necks that point upward, unlike other feathers that point downward. Studies show crested pigeons have less ability to kill bacteria because of lower kinase activity. The way a pigeon expresses the crest gene depends on its family background. For example, two baby pigeons from the same nest might have different crests: one with a pointed crest and the other with a smooth head.

Pigeons with feathers on their feet have different gene activity. A gene called PITX1, which usually helps develop legs, is less active in these pigeons. A gene called Tbx5, which normally helps develop wings, is active in their feet, causing feather growth and larger leg bones. These changes are due to differences in DNA regulation, not the genes themselves. Scientists study pigeon foot feathers to understand how non-avian dinosaurs might have transitioned from feathered to scaled feet. It is thought that flight feathers on feet were lost in all living birds because they made flying inefficient. Domestic pigeons overheat when flying with scaled feet, and scientists believe losing certain wing-like feathers on the feet improved flight efficiency.

Pouter or cropper breeds have a trait where they inflate their crops with air, creating a swollen "globe." This trait is partly inherited and more common in male pigeons. Some cropper breeds may have trouble passing food or water through their crops, but this is not always the case and can be managed by owners.

There is strong evidence that some differences between wild rock doves and domestic pigeons, like checkered wing patterns and red/brown colors, may come from crossbreeding with the speckled pigeon Columba guinea. However, genetic studies show little evidence of this, as C. guinea is more closely related to the common wood pigeon C. palumbus.

Domestic pigeons can be bred with barbary doves (Streptopelia risoria), but their offspring are not fertile.

Life history

Domestic pigeons reproduce in the same way as wild rock doves. They find a safe, cool spot to build a simple nest made of sticks and lay two eggs. The eggs are kept warm for about 17 to 19 days. A pigeon keeper may choose which pigeons mate, but in open lofts, pigeons pick their own partners. Both male and female pigeons are very protective of their eggs and young. They may fight to defend their nests from predators, including humans. They see their nests as part of their personal space.

Baby pigeons are called squabs, squeakers, or peepers. The names "squeakers" and "peepers" describe the sounds they make when asking for food. At first, squabs are fed by their parents using a special substance called crop milk, which is rich in protein and fat. Some pigeon breeds are bred in ways that make it hard for them to raise their young naturally. In these cases, humans may need to feed the squabs with special formula or place them with another pair of pigeons to care for them. This may also be needed if the parents cannot or will not raise the squab. When fed by their parents, squabs grow faster than other young birds, like quail. Raising squabs in human care may be more effective than using other pigeons to care for them.

As the chicks grow and become more active, their parents switch them to adult food, such as seeds and grains. A pigeon mother may begin a new nest before her previous young have left the nest. In this case, the father raises the older young alone. Pigeons reach adult size around four weeks old. After leaving the nest, the young follow their parents to communal feeding areas, which are places with plenty of food used by the flock. Here, the young learn to live independently and join the pigeon group.

Domestic pigeons were bred to reproduce faster than their wild ancestors. They do not have a specific breeding season, have plenty of food in their homes, and mature quickly. Young pigeons can leave the nest in about a month and may already have raised several groups of young before they are one year old. This leads to rapid population growth in flocks. Many pigeons are also lost during races or are intentionally released, which causes the number of wild pigeons to increase quickly.

• Feral pigeon nest with two eggs
• Nestlings, one day
• Nestling, five days
• Nestlings, about 10 days
• 18 days old
• Young bird, 22 days
• Feral pigeons in courtship

People who care for pigeons may develop a health problem called bird fancier’s lung or pigeon lung. This is a type of lung disease caused by breathing in proteins from pigeon feathers and droppings. It can sometimes be avoided by wearing a mask that filters the air. Other pigeon-related illnesses that affect the lungs include Chlamydophila psittaci (which causes psittacosis), Histoplasma capsulatum (which causes histoplasmosis), and Cryptococcus neoformans (which causes cryptococcosis). A virus called avian paramyxovirus, carried by pigeons, can cause sores and swelling in birds that are not vaccinated.

Avian mites can infest domestic pigeons and cause a condition called gamasoidosis in humans. Treatments for mites or lice in birds include using insecticides on the skin or giving medicine to eat.

Uses

Pigeons bred for meat are often called meat or utility breeds. The word "squab" can describe young pigeons or the meat taken from them. These young birds grow very large in the nest before they can fly. At this stage, they are often fattier and considered more flavorful than adult pigeons. During this time, squabs are valued as a food source. In ancient and early farming communities, squabs were an easy and dependable source of protein. These birds needed only a steady supply of grains and water, which they could find on their own. The rock formations they nested in were also useful for early humans as homes.

Pigeon meat, whether from squabs or adult birds, continues to be a food source around the world. Pigeons bred for meat as adults are called utility pigeons. For commercial meat production, a breed of large white pigeon called the King pigeon has been developed through selective breeding.

Homing pigeons are a special type of pigeon bred for navigation and speed. Originally trained to carry messages, especially during wars, these pigeons are still used in pigeon racing and in releasing white doves at events. These pigeons can return to their home loft even if released at a place they have never seen before, even if it is up to 1,000 km (620 miles) away. This ability requires two types of information: "map sense," which helps them know their location, and "compass sense," which tells them the direction to fly. These senses rely on different clues, such as the Earth's magnetic field. Scientists believe pigeons can detect magnetic fields using special tissues in their heads, though the exact location of these tissues is still being studied. Pigeons can sense magnetic fields as weak as 1.86 gauss.

Another theory suggests that pigeons use the sun's position and an internal clock to find direction. However, experiments show that pigeons can still find their way home even if these senses are disrupted. This suggests that pigeons use multiple clues for navigation, and map sense depends on comparing different clues.

Other possible clues used by pigeons include:
– Using the sun as a compass
– Navigating by stars at night
– Recognizing visual landmarks
– Using infrasound (very low sound) for navigation
– Detecting polarized light patterns
– Smelling certain scents

Pigeons are also kept by people for flying or sporting competitions. Unlike racers, these birds are not released far from their homes. Breeds like tipplers are bred to hover above their lofts for long periods. This ability shows that breeders can select for endurance.

Wild pigeons naturally flip or somersault to escape predators like falcons. These movements help them avoid attacks at the last moment. Tumbler and roller pigeons are bred to enhance this ability. Some pigeons can somersault on the ground and land on their feet, while others are bred to the point where their rolling ability prevents them from flying.

A breed called the zurito, known for its speed, is sometimes used in live pigeon shooting events.

Pigeon fanciers have created many unusual breeds through selective breeding. Simple display pigeons often have white feathers, either truly albino or with white feathers. These white birds were seen as symbols of peace and are common in ancient and modern culture.

As breeders gained more experience, they started selecting for more unusual traits, such as unique feather patterns, crests, foot feathering, and unusual behavior. These birds are generally called fancy pigeons.

Pigeon shows are events where fanciers and breeders gather to compete and trade their fancy pigeons. Breeds like "American show" pigeons were developed specifically to meet standards set by the National Pigeon Association. At these events, fanciers compete, and judges evaluate birds based on specific criteria to determine the best.

There are many fancy or ornamental pigeon breeds, including:
– English carrier pigeons, with prominent wattles and an upright stance
– Duchess pigeons, with feet covered in feather fans
– Fantails, with tail feathers resembling a peacock's
– Voorburg Shield Croppers, bred to inflate their crops to attract handlers
– Archangel, known for its iridescence
– Old Dutch Capuchine
– Lucerne Gold Collar
– Oriental Frill
– Old German Owl
– Old Dutch Owl
– English Owl
– Chinese Owl
– Valencian Figurita, one of the smallest breeds
– Portuguese tumbler, another small breed
– Old Dutch Tumbler
– The Giant Runt, one of the largest breeds
– Ghent Cropper
– Holle Cropper
– Silesian Cropper
– Voorburg Shield Cropper
– Norwich Cropper
– Pygmy pouter
– American Show Racer
– Dutch Beauty Homer
– Garden or English Fantail
– American Fantail
– Indian Fantail
– Danzig Highflyer
– Oriental Roller
– Birmingham Roller
– Danish Tumbler
– Zagreb Tumbler

Domestic pigeons are often used in scientific research. They help test medicines, chemicals, and study how the brain works. Research on pigeons covers topics like recognizing shapes, remembering things, and understanding concepts.

Pigeons have been trained to tell the difference between cubist and impressionist paintings. In a 1970s and 1980s U.S. Coast Guard project called "Project Sea Hunt," pigeons proved better than humans at finding shipwreck survivors at sea.

Pigeons can learn skills related to reading, such as recognizing letters, and basic math skills similar to those of primates. They have also been trained to sort medical images, such as detecting breast cancer, using their natural ability to recognize patterns.

Pigeons are sometimes kept as indoor pets, and this practice is becoming more popular. Pet pigeons may wear "pigeon pants" (a diaper-like garment) to stay clean, and some can be trained to use a specific area for waste.

Other relation to humans

Domestic pigeons, including those with white or pale coloring often called "white doves," have been used for symbolic purposes for a long time.

In the United States, some people who raise pigeons trap and kill hawks and falcons without permission to protect their birds. In the West Midlands area of the United Kingdom, pigeon enthusiasts have been accused of setting up traps to harm peregrine falcons. Eight illegal traps with spring-loaded mechanisms were found near peregrine nests, and at least one falcon died. These traps are believed to have been placed as part of an organized effort to harm as many falcons as possible in the region.

Over the years, many domestic pigeons have been released or escaped, leading to the creation of feral pigeons. These wild pigeons show a wide range of feather colors and patterns because of genes passed down from their parents. Some feral pigeons look similar to wild rock doves, while others have patterns inherited from their domestic ancestors. Over time, feral pigeon populations tend to become more similar in appearance, adapting to their environment, such as blending in with dark surfaces like asphalt. Feral pigeons with unique feather patterns are more likely to be caught by predators. The decline in pure wild dove populations is partly due to breeding between wild and feral pigeons. Domestic pigeons are often identified by a numbered metal or plastic band around one or both legs, showing they belong to an owner.

Feral pigeons are genetically similar to homing pigeons, suggesting many feral pigeons came from homing pigeons that did not return home or were bred by homing pigeons. The large number of pigeons released during races and the practice of abandoning pigeon lofts have contributed to the survival of urban feral pigeon populations. Feral pigeons began to be viewed negatively in the 1930s and 1940s. This criticism increased when New York City parks commissioner Thomas used the phrase "rats with wings" to describe them in June 1966.