|Feeding in a park|
|Dark red: approximate native range. Light red: introduced non-native populations|
Feral pigeons (Columba livia), also called city doves, city pigeons, or street pigeons, are derived from domestic pigeons that have returned to the wild. The domestic pigeon was originally bred from the wild Rock Dove, which naturally inhabits sea-cliffs and mountains. Rock (i.e., 'wild'), domestic, and feral pigeons are all the same species and will readily interbreed. Feral pigeons find the ledges of buildings to be a substitute for sea cliffs, have become adapted to urban life, and are abundant in towns and cities throughout much of the world.
|This section does not cite any references or sources. (February 2013)|
As a result of the continuous food supply, pigeon courtship rituals can be observed in urban parks at any time of the year. A male on the ground initially puffs up his feathers at the nape of the neck to appear larger and thereby impress or attract attention. He then singles out a female in the vicinity and approaches her at a rapid walking pace while emitting repetitive quiet notes, often bowing and turning as he comes closer.
Initially, the female invariably walks or flies a short distance away, and the male follows her. 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 make full- or half-pirouettes in front of the female.
The male then mounts the female. The mating is very brief with the male flapping his wings to maintain balance on top of the female. Sometimes the male and female beaks lock together.
Nests are rudimentary, similar to other ground or cliff nesting birds such as turkey, quail, and ducks. Abandoned buildings are favorite nesting areas. Mass nesting is common as pigeons are a community flocking bird; often dozens of birds will share a building. Loose tiles and broken windows provide access, and pigeons are adept at spotting new access points, for example following property damage caused by strong winds.
Nests and droppings tend to stay clustered and remain dry when out of the weather. Pigeons are particularly fond of roof spaces. These often contain water tanks. Any water tank or cistern on a roof must therefore be secured and sealed off to keep the pigeons out of them. The popularity of a nesting area does not seem to be affected by the pigeons population density.
On undamaged property, the gutters, window air conditioners and empty air conditioner containers, chimney pots and external ledges are used as nesting sites. Many building owners try to limit roosting by using bird control spikes and netting to cover ledges and potential nesting places on buildings. This has little effect on the size of the pigeon population, but it can reduce the accumulation of droppings on and around a particular building location.
In the UK, only the larger and more wary Common Wood Pigeon, which often shares the same territory and food supply, will build nests in trees, usually close to roads.
In Wendell Levi's The Pigeon, he describes the crowing/cooing of pigeons as mostly being associated with strutting and fighting in male birds. Hens will also coo, but this is noticeably less guttural than the cooing of the cock. Cooing is also more frequent between couples during mating and nesting. This is particularly prevalent amongst Rundle Pigeon's, which can become loud and aggressive during this season.
Both parents participate in the incubation of the eggs.
Pigeons breed when the food supply is abundant enough to support embryonic egg development, which in cities can be any time of the year. Laying of eggs can take place up to six times per year.
Pigeons mate for life, and are often found in pairs during the breeding season, but usually the pigeons are gregarious preferring to exist in flocks of from 50 to 500 birds (dependent on the food supply).
Feral pigeons can be seen eating grass seeds and berries in parks and gardens in the spring, but there are plentiful sources throughout the year from scavenging (e.g., remnants left inside of dropped fast-food cartons) and they will also take insects and spiders. Additional food is also usually available from the disposing of stale bread in parks by restaurants and supermarkets and from tourists buying and distributing birdseed, etc. Pigeons tend to congregate in large, often thick flocks when feeding on discarded food, and have been observed flying skillfully around trees, buildings, telephone poles and cables, and through moving traffic just to reach a food source.
Cities famous for pigeons 
Many city squares are famous for their large pigeon populations, for example, the Piazza San Marco in Venice, and Trafalgar Square in London. For many years, 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 banned in 2003 by London mayor Ken Livingstone. However, activist groups such as Save the Trafalgar Square Pigeons flouted the ban, feeding the pigeons from an area south of Nelson's Column in which the ban does not apply. The organisation has since come to an agreement to feed the pigeons only once a day, at 7:30 a.m.
Killing or injuring pigeons 
Under UK jurisdiction, anyone who injures or kills a pigeon will be dealt with according to the Wildlife Act and Countryside 1981 to injure, kill, or destroy nest.
According to the Royal Society for the Protection of Birds, the maximum penalty that can be imposed for an offence under the Wildlife and Countryside Act—in respect of a single bird, nest, or egg—is a fine of up to £5000, and/or six months' imprisonment.
Population control 
Feral pigeons often only have small populations within cities. For example, the breeding population of feral pigeons in Sheffield, England, has been estimated at only 12,130 individuals. Despite this, feral pigeons usually reach their highest densities in the central portions of cities, so they are frequently encountered by people, which leads to conflict.
Feral pigeons are often considered a pest or even vermin, owing to concerns that they spread disease and are much maligned in the media for transmitting bird flu, but it has been shown pigeons do not carry the deadly H5N1 strain. It is rare that a pigeon will transmit a disease to humans due to their immune system. Three studies have been done since the late 1990s by the US Agriculture Department's Southeast Poultry Research Laboratory in Athens, Georgia, according to the center's director, David Swayne. The lab has been working on bird flu since the 1970s.
In one experiment, researchers squirted into pigeons' mouths liquid drops that contained the highly pathogenic H5N1 virus from a Hong Kong sample. The birds got 100 to 1,000 times the concentration that wild birds would encounter in nature. "We couldn't infect the pigeons," Swayne said. "So that's good news."
The bacteria Chlamydophila psittaci is endemic among pigeons and causes Psittacosis in humans. It is transmitted both from handling pigeons but mostly from their droppings. Psittacosis is a serious disease but rarely fatal (less than 1%). Pigeons are also important vectors for different species of the bacteria Salmonella which causes diseases as Salmonellosis and Paratyphoid fever.
There is ample reason for the concerns of pigeons damaging property, due to their size and proximity to people and their dwellings. Pigeons often cause significant pollution with their droppings, though there is little evidence of them driving out other bird species. Pigeons are labeled an invasive species in North America by the USDA.
While pest exterminators use poison, hawks and nets have also been employed at ground level to control urban pigeon populations, though this generally achieves only a limited, temporary effect. Pigeons can often be seen trapped in nets on buildings and under bridges. Due to the fact that the Wildlife and Countryside Act 1981 is a Common Enforcer's Act, any member of the public can bring a private prosecution against a property owner if they see dead or dying birds trapped in or behind bird netting installations. The prosecution would use the Animal Welfare Act 2006 and be brought on the grounds of unnecessary suffering.  For further information http://www.pigeonprotectionandrescue.com
Long-term reduction of feral pigeon populations can be achieved by restricting food supply, which in turn involves 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. In addition, pigeon populations may be reduced by bird control systems that successfully reduce nesting sites.
Peregrine Falcons and other urban predators 
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. Projects include Unibase Falcon Project and the Victorian Peregrine Project.
Larger birds of prey occasionally take advantage of this population as well. In New York City, the abundance of pigeons (and other small animals) has created such a conducive environment for predators that the Red-Tailed Hawk has begun to return in very small numbers, the most famous of which is Pale Male.
Due to their non-selective nature, most avian poisons have been banned. In the United States market only 4-aminopyridine (Avitrol) and DRC-1339 remained registered by EPA. DRC-1339 is limited to USDA use only while 4-AP is a restricted use pesticide, for use only by licensed applicators.
The use of poisons has been 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. An additional problem with poisoning is that it also kills pigeon predators. Due to this, in cities with Peregrine Falcon programs it is typically illegal to poison pigeons.
Reducing food supply 
A more effective tactic to reduce the number of feral pigeons is deprivation. Cities around the world have discovered that not feeding their local birds results in a steady 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. Feeding of pigeons is banned in parts of Venice, Italy.
Avian contraceptives 
In 1998, in response to conservation groups and the public interest, the National Wildlife Research Center (NWRC), a USDA/APHIS laboratory in Fort Collins, Colorado, started work on nicarbazin, a promising compound for avian contraception. Originally developed for use in resident Canada geese, nicarbazin was introduced for use as a contraceptive for feral pigeons in 2007.
The active ingredient, nicarbazin, interferes with the viability of eggs by binding the ZP-3 sperm receptor site in the egg. This unique contraceptive action is non-hormonal and fully reversible.
Registered by the EPA as a pesticide (EPA Reg. No. 80224-1), "OvoControl P", brand of nicarbazin, is increasingly used in urban areas and industrial sites to control pigeon populations. Declared safe and humane, the new technology is environmentally benign and does not represent a secondary toxicity hazard to raptors or scavengers.
Avian contraception has the support of a range of animal welfare groups including the Humane Society of the United States (HSUS), the American Society for the Prevention of Cruelty to Animals (ASPCA) and People for the Ethical Treatment of Animals (PETA).
Dummy egg nesting 
Dummy egg nesting programs have been tested in some cities with mixed results. Nest or coop structures are erected and the eggs are removed and replaced with dummy eggs. The eggs are then disposed of to prevent the pigeons breeding. Such structures are being used in New York City and also the Melbourne city centre by the Melbourne City Council at Batman Park The loft used in Melbourne is on stilts, with a cage door allowing access from beneath for accessing structure at night when the pigeons are asleep.
See also 
|Wikimedia Commons has media related to: Columba livia|
- "Science & Nature: Animals: Feral Pigeon" (Web article). BBC.CO.UK. Retrieved 2008-01-05.
- Levi, Wendell (1977). The Pigeon. Sumter, S.C.: Levi Publishing Co, Inc. ISBN 0-85390-013-2.
- "WHY STUDY PIGEONS? To understand why there are so many colors of feral pigeons." (Web Article). Cornell Lab of Ornithology. Retrieved 2008-01-06.
- Gibbs, David; Eustace Barnes, John Cox. Pigeons and Doves: A Guide to the Pigeons and Doves of the World. United Kingdom: Pica Press. p. 624. ISBN 1-873403-60-7.
- "Feeding Trafalgar's pigeons illegal". BBC News. 2003-11-17.
- "Save the Trafalgar Square Pigeons - Background". Savethepigeons.org. Retrieved 2012-08-29.
- Fuller RA, Tratalos J, Gaston KJ (2009). "How many birds are there in a city of half a million people?". Diversity and Distributions 15 (2): 328–337. doi:10.1111/j.1472-4642.2008.00537.x.
- "Facts about pigeon-related diseases" (Web article). The New York City Department of Health and Mental Hygiene. Retrieved 2008-01-04.
- Turner, Brad. "Avian flu virus H5N1 and pigeons: the facts." (Web article). Purebred Pigeon Magazine. Retrieved 2008-01-04.
- Panigrahy B, Senne DA, Pedersen JC, Shafer AL, Pearson JE (1996). "Susceptibility of pigeons to avian influenza". Avian Dis. (American Association of Avian Pathologists, Inc.) 40 (3): 600–4. doi:10.2307/1592270. JSTOR 1592270. PMID 8883790.
- Paulik, Laurie. "Pigeons" (Web article). AgNIC Wildlife Damage Management. Retrieved 2008-01-04.
- Pigeon Control Advisory Service. "Bird Control and the Law". PiCAS uk.
- Blechman, Andrew (2007). Pigeons-The fascinating saga of the world's most revered and reviled bird.. St Lucia, Queensland: University of Queensland Press. ISBN 978-0-7022-3641-9.
- Kleinman, Rachel (2007-10-19). "Fastest bird on earth enjoys family time high above city street". The Age (Melbourne).
- "Eyes in the sky". BBC News. 2010-06-16.
- Nick - Web Team (2009-06-24). "Natural selection on the roof of Wrexham police station". North East Wales Weblog:. BBC. Retrieved 2012-08-29.
- [Andrew] (2007). Pigeons-The fascinating saga of the world's most revered and reviled bird.. St Lucia, Queensland: University of Queensland Press. ISBN 978-0-7022-3641-9.
- Feral Pigeons in Bexley[dead link]
- The New York Times - Breaking News, World News & Multimedia
- Reinoso, V., A. MacDonald and G.F. Barbato. Nicarbazin reduces egg production and fertility in White Pekin Ducks. Accepted for publication in Poultry Science.
- Avery, M., K. Keacher, and E. Tillman. Nicarbazin bait reduces reproduction by pigeons (Columba livia). 2008. Wildlife Research 35(1) 80-85
- EPA Fact Sheet: Nicarbazin http://wayback.archive.org/web/20120625211506/http://www.epa.gov/opprd001/factsheets/nicarbazin.pdf
- "'Rats with wings': a history of the urban pigeon - Rear Vision - ABC Radio National (Australian Broadcasting Corporation)". Abc.net.au. Retrieved 2012-08-29.