Feral Pigeon

Feral Rock Pigeon
Feral Rock Pigeons feeding in a park
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Columbiformes
Family:	Columbidae
Genus:	Columba
Species:	C. livia
Binomial name
Columba livia Gmelin, 1789
Distribution

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. All pigeons are one species (columba livia). Feral pigeons find the ledges of buildings to be a substitute for sea cliffs, and have become adapted to urban life and are abundant in towns and cities throughout much of the world.

Breeding

Courtship

Courting pigeons in Kolkata

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.

Nesting

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 give pigeons access; they are good 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.

Pigeon squab in nest

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.

Cooing

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.

Both parents participate in the incubation of the eggs.

Food

A pigeon perched in Central Park

Pigeons breed when the food supply is good, 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.

Video showing a pigeon eating seeds

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., dropped fast-food cartons) and they will also take insects and spiders. 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 skilfully around trees, buildings, telephone poles and cables, and even moving traffic just to reach it.

See also: Reproduction of Rock Pigeons

Cities famous for pigeons

London's Trafalgar Square.

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.

Population control

See also: Animal population control

Many places where pigeons could land are covered with spikes.

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.

A large pigeon trap/coop/loft at Batman Park, Melbourne. Designed specifically to encourage nesting and allow removal of fertilised eggs to prevent population growth, it is a landmark in its own right.

One of the difficulties of controlling pigeon populations is the common practice of feeding them, as here in New York.

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. Much of the media attention about pigeons carrying disease or causing properrty damage is attributed to the pest control companies working to drum up business. 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 Agriculture Department's Southeast Poultry Research Laboratory in Athens, Ga., said 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."

There is no basis in fact for the concerns of pigeons damaging property, causing pollution with their excrement, and driving out other bird species. Some also incorrectly consider pigeons an invasive species.

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.

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

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.

In Wrexham, Wales, Uk a pair of peregrine falcons has nested since 2002, first on top of st giles church and for the last four years on top of Wrexham police station next to the swimming baths.

Poison

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

See also: Wildlife contraceptive

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).

USDA continues to develop wildlife contraceptives, including the recently registered Gonadotropin-releasing hormone (GnRH) for deer and Diazacon for birds and small mammals. Further development and registrations of Porcine Zona Pellucida or PZP, another immunocontraceptive targeted for feral horses, is supported by HSUS. The new field of wildlife contraceptives is developing rapidly and promises a bright future for the safe, effective and humane management of animal populations.

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^{[citation needed]} 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.

Ancient Dovecotes

See also: Dovecote

The use of dovecotes as a pigeon control option is still relatively uncommon, in spite of the fact that pigeons were successfully domesticated and bred in similar facilities centuries ago. The main reason that dovecotes are not used more extensively as a pigeon control option is due to the highly negative press that pigeons have received courtesy of propaganda circulated by the pest control industry and the media’s over-dramatised and often fictional interpretation of it. Pigeons are commonly (but wrongly) perceived as disease carriers and thereby a major threat to human health, but in reality the chances of a human being becoming ill as a result of contact with pigeons or their excrement is virtually zero. Nonetheless pigeons have been given a bad name and that name has stuck, resulting in the public having an unnatural and unfounded fear of contact with pigeons. Even so, it is human beings that are responsible for the huge numbers of feral pigeons that we see in towns and cities all over the world. Deliberate and persistent feeding of pigeons by a relatively small number of people has resulted in pigeon populations dramatically increasing in size and as a result, causing significant problems for property owners. In reality, it is these problems (ie. the soiling of buildings used for perching and roosting) that are the main reason that pigeons are controlled, not the perceived health risks.

Modern Dovecotes

A dovecote combined with a designated feeding area can be used in situations where the deliberate public feeding of pigeons is seen to be the root cause of the problem and where a reduction in flock size is the goal. The only body able to provide a system of this nature would be a council or a town or city center management agency. The basic principal of the system is to provide a centralized feeding area where the public feeding of pigeons is allowed in an effort to stop the random feeding of pigeons taking place throughout a town or city center. Once the feeding facility has been provided, a public information program would need to be initiated designed to educate the public about the problems associated with feeding pigeons and the advantages to both pigeons and property owners of feeding exclusively in a centralized feeding facility.

A perching facility could be provided above or adjacent to the feeding area and upon which pigeons would perch during the daytime whilst exploiting food provided within the area. This would ensure that pigeons using the feeding facility did not perch on buildings in the vicinity thereby causing soiling problems for property owners. When a reduction in pigeon numbers is required, a dovecote facility should be provided which will not only provide pigeons with a daytime perch but also with an overnight roosting and breeding facility where flock size can be controlled by birth control. This is achieved by removing eggs, as laid, from the dovecote and replacing them with dummy eggs. This method of control will dramatically reduce pigeon flock size and is cheap and simple to maintain. The infrastructure required to implement this type of system is straightforward.

A loft-based system will involve the use of specially designed pigeon lofts that will be sited on a building (on a flat roof area for example) or in various locations around a site. These lofts will usually be no larger than an average sized garden shed and will be basic in design. Lofts are a cost-effective and holistic means of centralizing and controlling pigeon flock size. Set-up costs for this type of system will normally not exceed a few hundred dollars and the cost of servicing the lofts will be low based on an average of 10 minutes human interaction per week. The principal of this system is to encourage pigeons away from their existing roosting and perching areas, with deterrents and anti-roosting products where necessary, and into the loft facilities where they are encouraged to roost and breed. Then, as with dovecotes, eggs will be removed and replaced with dummy eggs and flock size on the building or site concerned will reduce rapidly. This method of control is of particular benefit where pigeon-related problems are entrenched or where the installation of deterrents and anti-roosting products is complex or cost-prohibitive.

This is so effective because pigeons are prolific breeders. Pigeons breed all year round and produce 2 young each time they breed. A normal pair of adult pigeons can produce up to 16 young each year in optimum conditions. Therefore, irrespective of what conventional controls are provided, if breeding continues unrestricted flock size can increase at a staggering rate.

The following example, based on one breeding pair of pigeons over the period of 12 months, gives an idea of how effective one small dovecote can be:

• One adult pair of pigeons produce 13/14 young per year in optimum conditions -taking 15% juvenile mortality into consideration-

• Those young birds form into 6 further breeding pairs and each young pair breeds once in their first year of life bringing approximately 10 more young into the world -taking 15% juvenile mortality into consideration-

• The original adult pair has produced 13/14 young and these young birds have paired and produced a further 10 young birds

• This is a total of 23/24 young birds produced courtesy of the original adult pair in one year

• If you persuade the original adult pair to use an artificial breeding facility instead of breeding in an uncontrolled environment the result is that 23/24 young birds are taken out of the system in one year via egg removal/replacement with dummy eggs

• Therefore, if 50 adult pairs are resident in one loft and all their eggs are removed over a 12 month period the number of young birds taken out of the system rises to over 1150, courtesy of one pigeon loft.

See also

• Birdfeeding
• Doves as Symbols

Books

• Levi, Wendell (1977). The Pigeon. Sumter, S.C.: Levi Publishing Co, Inc. ISBN 0853900132.